MSX2-Technical-Handbook

CHAPTER 4 - VDP AND DISPLAY SCREEN (Section 6)

6. VDP COMMAND USAGE

MSX-VIDEO can execute basic graphic operations, which are called VDP commands. These are done by accessing special harware and are available in the GRAPHIC 4 to GRAPHIC 7 modes. These graphic commands have been made easy to implement, requiring only that the necessary parameters be set in the proper registers before invoking them. This section describes these VDP commands.

 

Index

6. VDP COMMAND USAGE

6.1 Coordinate System of VDP Commands

6.2 VDP Commands

6.3 Logical Operations

6.4 Area Specification

6.5 Use of Each Command

6.5.1 HMMC (CPU -> VRAM high-speed transfer)

6.5.2 YMMM (high-speed transfer between VRAM in Y direction)

6.5.3 HMMM (high-speed transfer between VRAM)

6.5.4 HMMV (painting the rectangle in high speed)

6.5.5 LMMC (CPU -> VRAM logical transfer)

6.5.6 LMCM (VRAM - CPU logical transfer)

6.5.7. LMMM (VRAM->VRAM logical transfer)

6.5.8 LMMV (VRAM logical paint)

6.5.9 LINE (drawing a line)

6.5.10 SRCH (colour code search)

6.5.11 PSET (drawing a point)

6.5.12 POINT (reading a colour code)

6.6 Speeding Up Commands

6.7 Register Status at Command Termination

Changes from the original

 

6.1 Coordinate System of VDP Commands

When VDP commands are executed, the location of the source and destination points are represented as (X, Y) coordinates as shown in Figure 4.72. When commands are executed, there is no page division and the entire 128K bytes VRAM is placed in a large coordinate system.

Figure 4.72 Coordinate system of VRAM
    GRAPHIC 4  (SCREEN 5)                       GRAPHIC 5  (SCREEN 6)
------------------------------    00000H    ------------------------------
| (0,0)              (255,0) |      |       | (0,0)              (511,0) |
|           Page 0           |      |       |           Page 0           |
| (0,255)          (255,255) |      |       | (0,255)          (511,255) |
|----------------------------|    08000H    |----------------------------|
| (0,256)          (255,256) |      |       | (0,256)          (511,256) |
|           Page 1           |      |       |           Page 1           |
| (0,511)          (255,511) |      |       | (0,511)          (511,511) |
|----------------------------|    10000H    |----------------------------|
| (0,512)          (255,512) |      |       | (0,512)          (511,512) |
|           Page 2           |      |       |           Page 2           |
| (0,767)          (255,767) |      |       | (0,767)          (511,767) |
|----------------------------|    18000H    |----------------------------|
| (0,768)          (255,768) |      |       | (0,768)          (511,768) |
|           Page 3           |      |       |           Page 3           |
| (0,1023)        (255,1023) |      |       | (0,1023)        (511,1023) |
------------------------------    1FFFFH    ------------------------------

    GRAPHIC 7  (SCREEN 8)                       GRAPHIC 6  (SCREEN 7)
------------------------------    00000H    ------------------------------
| (0,0)              (255,0) |      |       | (0,0)              (511,0) |
|           Page 0           |      |       |           Page 0           |
| (0,255)          (255,255) |      |       | (0,255)          (511,255) |
|----------------------------|    10000H    |----------------------------|
| (0,256)          (255,256) |      |       | (0,256)          (511,256) |
|           Page 1           |      |       |           Page 1           |
| (0,511)          (255,511) |      |       | (0,511)          (511,511) |
------------------------------    1FFFFH    ------------------------------

 

6.2 VDP Commands

There are 12 types of VDP commands which can be executed by MSX-VIDEO. These are shown in Table 4.5.

Table 4.5 List of VDP commands
----------------------------------------------------------------------------
| Command name | Destination | Source | Units | Mnemonic | R#46 (4 hi ord) |
|--------------+-------------+--------+-------+----------+-----------------|
|              |    VRAM     |  CPU   | bytes |   HMMC   |  1   1   1   1  |
| High speed   |    VRAM     |  VRAM  | bytes |   YMMM   |  1   1   1   0  |
| move         |    VRAM     |  VRAM  | bytes |   HMMM   |  1   1   0   1  |
|              |    VRAM     |  VDP   | bytes |   HMMV   |  1   1   0   0  |
|--------------+-------------+--------+-------+----------+-----------------|
|              |    VRAM     |  CPU   | dots  |   LMMC   |  1   0   1   1  |
| Logical      |    CPU      |  VRAM  | dots  |   LMCM   |  1   0   1   0  |
| move         |    VRAM     |  VRAM  | dots  |   LMMM   |  1   0   0   1  |
|              |    VRAM     |  VDP   | dots  |   LMMV   |  1   0   0   0  |
|--------------+-------------+--------+-------+----------+-----------------|
| Line         |    VRAM     |  VDP   | dots  |   LINE   |  0   1   1   1  |
|--------------+-------------+--------+-------+----------+-----------------|
| Search       |    VRAM     |  VDP   | dots  |   SRCH   |  0   1   1   0  |
|--------------+-------------+--------+-------+----------+-----------------|
| Pset         |    VRAM     |  VDP   | dots  |   PSET   |  0   1   0   1  |
|--------------+-------------+--------+-------+----------+-----------------|
| Point        |    VDP      |  VRAM  | dots  |   POINT  |  0   1   0   0  |
|--------------+-------------+--------+-------+----------+-----------------|
|              |    ----     |  ----  | ----- |   ----   |  0   0   1   1  |
| Reserved     |    ----     |  ----  | ----- |   ----   |  0   0   1   0  |
|              |    ----     |  ----  | ----- |   ----   |  0   0   0   1  |
|--------------+-------------+--------+-------+----------+-----------------|
| Stop         |    ----     |  ----  | ----- |   ----   |  0   0   0   0  |
----------------------------------------------------------------------------

 

6.3 Logical Operations

When commands are executed, various logical operations can be done between data in VRAM and the specified data. Each operation will be done according to the rules listed in Table 4.6.

In the table, SC represents the source color and DC represents the destination colour. IMP, AND, OR, EOR and NOT write the result of each operation to the destination. In operations whose names are preceded by “T”, dots which correspond with SC=0 are not the objects of the operations and remains as DC. Using these operations enables only colour portions of two figures to be overlapped, so they are especially effective for animations.

List 4.7 shows an example of these operations.

Table 4.6 List of logical operations
-------------------------------------------------------------------------
| Logical name |                                        |L03 L02 L01 L00|
|--------------+----------------------------------------+---------------|
|              |                                        |               |
|     IMP      | DC=SC                                  | 0   0   0   0 |
|              |                                        |               |
|     AND      | DC=SCxDC                               | 0   0   0   1 |
|              |                                        |               |
|     OR       | DC=SC+DC                               | 0   0   1   0 |
|              |    __       __                         |               |
|     EOR      | DC=SCxDC+SCxDC                         | 0   0   1   1 |
|              |    __                                  |               |
|     NOT      | DC=SC                                  | 0   1   0   0 |
|              |                                        |               |
|     ----     |                                        | 0   1   0   1 |
|              |                                        |               |
|     ----     |                                        | 0   1   1   0 |
|              |                                        |               |
|     ----     |                                        | 0   1   1   1 |
|              |                                        |               |
|--------------+----------------------------------------+---------------|
|              |                                        |               |
|     TIMP     | if SC=0 then DC=DC else DC=SC          | 1   0   0   0 |
|              |                                        |               |
|     TAND     | if SC=0 then DC=DC else DC=SCxDC       | 1   0   0   1 |
|              |                                        |               |
|     TOR      | if SC=0 then DC=DC else DC=SC+DC       | 1   0   1   0 |
|              |                            __       __ |               |
|     TEOR     | if SC=0 then DC=DC else DC=SCxDC+SCxDC | 1   0   1   1 |
|              |                            __          |               |
|     TNOT     | if SC=0 then DC=DC else DC=SC          | 1   1   0   0 |
|              |                                        |               |
|     ----     |                                        | 1   1   0   1 |
|              |                                        |               |
|     ----     |                                        | 1   1   1   0 |
|              |                                        |               |
|     ----     |                                        | 1   1   1   1 |
|              |                                        |               |
-------------------------------------------------------------------------
List 4.7 Example of the logical operation with T
1000 '***********************************************************
1010 '  List 4.7   logical operation with T
1020 '***********************************************************
1030 '
1040 SCREEN8 : COLOR 15,0,0 : CLS
1050 DIM A%(3587)
1060 '
1070 LINE (50,50)-(60,100),48,8 : PAINT (51,51),156,48
1080 CIRCLE (55,30),30,255 : PAINT (55,30),240,255
1090 COPY(20,0)-(90,100) TO A%
1100 CLS
1110 '
1120 R=RND(-TIME)
1130 FOR Y=0 TO 100 STEP 3
1140   X=INT(RND(1)*186)
1150   COPY A% TO (X,Y),,TPSET
1160 NEXT
1170 '
1180 GOTO 1180

 

6.4 Area Specification

AREA-MOVE commands are for transferring screen data inside areas surrounded by a rectangle. The area to be transferred is specified by one vertex and the length of each side of the rectangle as shown in Figure 4.73. SX and SY represent the basic point of the rectangle to be transferred and NX and NY represent the lengt of each side in dots. The two bits, DIX and DIY, are for the direction of transferring data (the meaning of DIX and DIY depends on the type of command). The point where the area is to be transferred is specified in DX and DY.

Figure 4.73 Area specification
----------------------------------------------------------------
|                                                              |
|     (SX,SY)                                                  |
|       x----------------- -->                                 |
|       |                | DIX                                 |
|       |                |                                     |
|       |                |                                     |
|       |                |                                     |
|       ------------------  --+                                |
|       | DIY                 |                                |
|       V                     |                                |
|                             |      (DX,DY)                   |
|                             +->  x-----------------          |
|                                  |                |          |
|                                  |                |          |
|                                  |                |          |
|                                  |                |          |
|                                  ------------------          |
|                                                              |
----------------------------------------------------------------

 

6.5 Use of Each Command

Commands are clasified into three types, high-speed transfer commands, logical transfer commands, and drawing commands. This section describes the commands and their use.

 

6.5.1 HMMC (CPU -> VRAM high-speed transfer)

Data is transferred into the specified area of VRAM from the CPU (see Figure 4.74). Logical operations cannot be specified. Data is transferred in bytes in high-speed transfer commands such as HMMC. Note that the low order bit of the X-coordinate is not referred to in GRAPHIC 4, or 6 modes. The two low order bits are not referred to in GRAPHIC 5 mode (see Figure 4.75).

Set the parameters as shown in Figure 4.76 to the appropriate registers. At this point, write only the first byte of data to be transferred from the CPU in R#44. Writing the command code F0H in R#46 causes the command to be executed, and UMSX-VIDEO receives data from R#44 and writes it to VRAM, then waits for data from the CPU.

The CPU writes data after the second byte in R#44. Note that data should be transferred after MSX-VIDEO can receive data (in the case that TR bit is “1”), referring to TR bit of S#2. When the CE bit of S#2 is “0”, this means that all data has been transferred (see figure 4.77). List 4.8 shows an example of using HMMC.

Figure 4.74 Action of HMMC command
              VRAM or expansion RAM
---------------------------------------------------
|                                                 |   MSX-VIDEO      CPU
|                                                 |    -------     -------
|    (DX,DY)                                      |    |     |     |     |
|       x------------------------ --> DIX         |    |     |     |     |
|       |          NX           |                 |    |     |     |     |
|       | NY                    |<----------------+----|     |-----|     |
|       |                       |                 |    |     |     |     |
|       -------------------------                 |    |     |     |     |
|       | DIY                                     |    |     |     |     |
|       V                                         |    |     |     |     |
|                                                 |    -------     -------
|                                                 |
---------------------------------------------------

MXD: select the destination memory      0 = VRAM, 1 = expansion RAM

NX:  number of dots to be transferred in X direction (0 to 511)*
NY:  number of dots to be transferred in Y direction (0 to 1023)

DIX: direction of NX from the origin    0 = right, 1 = left
DIY: direction of NY from the origin    0 = below, 1 = above

DX:  destination origin  X-coordinate (0 to 511)*
DY:  destination origin  Y-coordinate (0 to 1023)

CLR (R#44:Colour register):  1st byte of data to be transferred

* The one low-order bit for GRAPHIC 4 and 6 modes, 
  or two low-order bits for GRAPHIC 5 mode of the DX and NX registers are ignored.
Figure 4.75 Dots not to be referred to
       MSB   7    6    5    4    3    2    1    0    LSB
           -----------------------------------------
GRAPHIC 4  |    :    :    :    |    :    :    :    |
           -----------------------------------------
                    (1)                 (2)
Since 1 VRAM byte represents 2 dots, 1 low order bit of X-coordinate is not referred to.

       MSB   7    6    5    4    3    2    1    0    LSB
           -----------------------------------------
GRAPHIC 5  |    :    |    :    |    :    |    :    |
           -----------------------------------------
               (1)       (2)       (3)       (4)
Since 1 VRAM byte represents 4 dots, 2 low order bits of X-coordinate are not referred to.

       MSB   7    6    5    4    3    2    1    0    LSB
           -----------------------------------------
GRAPHIC 6  |    :    :    :    |    :    :    :    |
           -----------------------------------------
                    (1)                 (2)
Since 1 VRAM byte represents 2 dots, 1 low order bit of X-coordinate is not referred to.
Figure 4.76 Register settings of HMMC command
> HMMC register setup

    MSB   7    6    5    4    3    2    1    0    LSB
        -----------------------------------------
R#36    | DX7| DX6| DX5| DX4| DX3| DX2| DX1| DX0|
        ----------------------------------------- DX ---+
R#37    | 0  | 0  | 0  | 0  | 0  | 0  | 0  | DX8|       |
        -----------------------------------------       |
                                                        | destination origin
        -----------------------------------------       |
R#38    | DY7| DY6| DY5| DY4| DY3| DY2| DY1| DY0|       |
        ----------------------------------------- DY ---+
R#39    | 0  | 0  | 0  | 0  | 0  | 0  | DY9| DY8|
        -----------------------------------------

        -----------------------------------------
R#40    | NX7| NX6| NX5| NX4| NX3| NX2| NX1| NX0|
        ----------------------------------------- NX ⟶ Number of dots in X direction to be transferred
R#41    | 0  | 0  | 0  | 0  | 0  | 0  | 0  | NX8|
        -----------------------------------------

        -----------------------------------------
R#42    | NY7| NY6| NY5| NY4| NY3| NY2| NY1| NY0|
        ----------------------------------------- NY ⟶ Number of dots in Y direction to be transferred
R#43    | 0  | 0  | 0  | 0  | 0  | 0  | NY9| NY8|
        -----------------------------------------

        -----------------------------------------                     --+
R#44    | CR7| CR6| CR5| CR4| CR3| CR2| CR1| CR0| CLR (GRAPHIC 4,6)     |
        -----------------------------------------                       |
        |                   |                   |                       |
        +-------------------+-------------------+                       |
                X=2N               X=2N+1         (N=0, 1, ..., 127)    |
                                                                        |
        -----------------------------------------                       |
        | CR7| CR6| CR5| CR4| CR3| CR2| CR1| CR0| CLR (GRAPHIC 5)       | data to be transferred
        -----------------------------------------                       |
        |         |         |         |         |                       |
        +---------+---------+---------+---------+                       |
           X=4N     X=4N+1    X=4N+2    X=4N+3    (N=0, 1, ..., 127)    |
                                                                        |
        -----------------------------------------                       |
        | CR7| CR6| CR5| CR4| CR3| CR2| CR1| CR0| CLR (GRAPHIC 7)       |
        -----------------------------------------                     --+
                      1 byte per dot

        -----------------------------------------
R#45    |  0 | -- | MXD| -- | DIY| DIX| -- | -- | ARG (Argument register)
        -----------------------------------------
                     |         |   direction (X)
                     |         |
                     |         +-> direction (Y)
                     |
                     +-----------> select destination memory

> HMMC command execution

    MSB   7    6    5    4    3    2    1    0    LSB
        -----------------------------------------
R#46    | 1  | 1  | 1  | 1  | -- | -- | -- | -- | CMR
        -----------------------------------------
Figure 4.77 HMMC command execution flow chart
        /-------------------\
        |     HMMC start    |
        \-------------------/
                  |
        ---------------------
        |   register setup  |
        ---------------------
                  |
        ---------------------
        | command execution |
        ---------------------
                  |
+---------------->|
|                 |
|    ---------------------------
|    | Read status register #2 |
|    ---------------------------
|                 |
|       //////////+\\\\\\\\\\ Yes (CE bit = 0)
|       |   command end?    |-------------------+
|       \\\\\\\\\\+//////////                   |
|                 | No (CE bit = 1)             |
|       //////////+\\\\\\\\\\                   |
|<------|     transfer?     |                   |
| No    \\\\\\\\\\+//////////                   |
| (TR bit=0)      | Yes (TR bit = 1)            |
|       ---------------------                   |
|       |   transfer data   |                   |
|       ---------------------                   |
|                 |                             |
+-----------------+                             |
                                                |
                  +-----------------------------+
                  |
                  V
        /--------------------\
        |      HMMC end      |
        \--------------------/
List 4.8 Example of HMMC command execution
;****************************************************************
;  List 4.8   HMMC sample
;               to use, set H, L, D, E, IX and go
;               RAM (IX) ⟶ VRAM (H,L)-(D,E)
;****************************************************************
;
RDVDP:  EQU     0006H
WRVDP:  EQU     0007H

;----- program start -----

HMMC:   DI                              ;disable interrupt
        CALL    WAIT.VDP                ;wait end of command

        LD      A,(WRVDP)
        LD      C,A
        INC     C                       ;C := PORT#1's address
        LD      A,36
        OUT     (C),A
        LD      A,17+80H
        OUT     (C),A                   ;R#17 := 36

        INC     C
        INC     C                       ;C := PORT#3's address
        XOR     A
        OUT     (C),H                   ;DX
        OUT     (C),A
        OUT     (C),L                   ;DY
        OUT     (C),A

        LD      A,H                     ;make NX and DIX
        SUB     A
        LD      D,00000100B
        JR      NC,HMMC1
        LD      D,00000000B
        NEG
HMMC1:  LD      H,A                     ;H := NX , D := DIX

        LD      A,L
        SUB     A
        LD      E,00001000B
        JR      NC,HMMC2
        LD      E,00000000B
        NEG
HMMC2:  LD      L,A                     ;L := NY , E := DIY

        XOR     A
        OUT     (C),H                   ;NX
        OUT     (C),A
        OUT     (C),L                   ;NY
        OUT     (C),A
        LD      H,(IX+0)
        OUT     (C),H                   ;first DATA
        LD      A,D
        OR      E
        OUT     (C),A                   ;DIX and DIY
        LD      A,0F0H
        OUT     (C),A                   ;HMMC command

        LD      A,(WRVDP)
        LD      C,A                     ;C := PORT#1's address
        INC     C
        LD      A,44+80H
        OUT     (C),A
        LD      A,17+80H
        OUT     (C),A
        INC     C
        INC     C

LOOP:   LD      A,2
        CALL    GET.STATUS
        BIT     0,A                     ;check CE bit
        JR      Z,EXIT
        BIT     7,A                     ;check TR bit
        JR      Z,LOOP
        INC     IX
        LD      A,(IX+0)
        OUT     (C),A
        JR      LOOP

EXIT:   LD      A,0
        CALL    GET.STATUS              ;when exit, you must select S#0
        EI
        RET

GET.STATUS:                             ;read status register specified by A
        PUSH    BC
        LD      BC,(WRVDP)
        INC     C
        OUT     (C),A
        LD      A,8FH
        OUT     (C),A
        LD      BC,(RDVDP)
        INC     C
        IN      A,(C)
        POP     BC
        RET

WAIT.VDP:                               ;wait VDP ready
        LD      A,2
        CALL    GET.STATUS
        AND     1
        JR      NZ,WAIT.VDP
        XOR     A
        CALL    GET.STATUS
        RET

        END

 

6.5.2 YMMM (high-speed transfer between VRAM in Y direction)

Data from a specified VRAM area is transferred into another area in VRAM. Note that transfers using this command can only be done in the Y direction (see Figure 4.78).

After setting the data as shown in Figure 4.79 in the proper registers, writing command code E0H in R#46 causes the command to be executed. When the CE bit of S#2 is “1”, it indicates that the command is currently being executed. List 4.9 shows an example of using YMMM.

Figure 4.78 Actions of YMMM command
              VRAM or expansion RAM
---------------------------------------------------
|                                                 |
|                (DX,DY)                          |
|                        x------------------------|
|                        |                        |
|                        |                        |
|                        |                        |
|                        -------------------------|
|                                    ^            |
|                                    |            |
|                                    |            |
|                (DX,SY)                          |
|                        x------------------------| ⟶ DIX
|                        |                        |
|                        | NY                     |
|                        |                        |
|                        -------------------------|
|                        | DIY                    |
|                        V                        |
---------------------------------------------------

MXD: select the destination memory      0 = VRAM, 1 = expansion RAM

SY:  source origin Y-coordinate (0 to 1023)

NY:  number of dots to be transferred in Y direction (0 to 1023)

DIX: set which to be transferred, to te right end or to the left end of the
     screen from the source origin      0 = right, 1 = left
DIY: direction of NY from the origin    0 = below, 1 = above

DX:  destination origin  X-coordinate (0 to 511)*
DY:  destination origin  Y-coordinate (0 to 1023)

* The one low-order bit for GRAPHIC 4 and 6 modes, 
  or two low-order bits for GRAPHIC 5 mode of the DX register are ignored.
Figure 4.79 Register settings of YMMM command
> YMMM register setup

    MSB   7    6    5    4    3    2    1    0    LSB
        -----------------------------------------
R#34    | SY7| SY6| SY5| SY4| SY3| SY2| SY1| SY0|
        ----------------------------------------- SY ⟶ source origin
R#35    | 0  | 0  | 0  | 0  | 0  | 0  | SY9| SY8|
        -----------------------------------------

        -----------------------------------------
R#36    | DX7| DX6| DX5| DX4| DX3| DX2| DX1| DX0|
        ----------------------------------------- DX ⟶ destination and source origin
R#37    | 0  | 0  | 0  | 0  | 0  | 0  | 0  | DX8|
        -----------------------------------------

        -----------------------------------------
R#38    | DY7| DY6| DY5| DY4| DY3| DY2| DY1| DY0|
        ----------------------------------------- DY ⟶ destination origin
R#39    | 0  | 0  | 0  | 0  | 0  | 0  | DY9| DY8|
        -----------------------------------------

        -----------------------------------------
R#42    | NY7| NY6| NY5| NY4| NY3| NY2| NY1| NY0|
        ----------------------------------------- NY ⟶ number of dots to be transferred in Y direction
R#43    | 0  | 0  | 0  | 0  | 0  | 0  | NY9| NY8|
        -----------------------------------------

        -----------------------------------------
R#45    |  0 | -- | MXD| -- | DIY| DIX| -- | -- | ARG (Argument register)
        -----------------------------------------
                     |         |   direction (X)
                     |         |
                     |         +-> direction (Y)
                     |
                     +-----------> select destination memory

> YMMM command execution

    MSB   7    6    5    4    3    2    1    0    LSB
        -----------------------------------------
R#46    | 1  | 1  | 1  | 0  | -- | -- | -- | -- | CMR
        -----------------------------------------
List 4.9 Example of YMMM command execution
;****************************************************************
;  List 4.9   YMMM sample
;               to use, set L, E, B, C, D(bit 2) and go
;               VRAM (B,L)-(*,E) ⟶ VRAM (B,C)
;               DIX must be set in D(bit 2)
;****************************************************************
;
RDVDP:  EQU     0006H
WRVDP:  EQU     0007H

;----- program start -----

YMMM:   DI                              ;disable interrupt
        PUSH    BC                      ;save destination
        CALL    WAIT.VDP                ;wait end of command

        LD      A,(WRVDP)
        LD      C,A
        INC     C                       ;C := PORT#1's address
        LD      A,34
        OUT     (C),A
        LD      A,17+80H
        OUT     (C),A                   ;R#17 := 34

        INC     C
        INC     C                       ;C := PORT#3's address
        XOR     A
        OUT     (C),L                   ;SY
        OUT     (C),A

        LD      A,L                     ;make NY and DIY
        SUB     A
        LD      E,00001000B
        JP      NC,YMMM1
        LD      E,00000000B
        NEG
YMMM1:  LD      L,A                     ;L := NY , D := DIY

        LD      A,D
        OR      E

        POP     DE                      ;restore DX,DY
        PUSH    AF                      ;save DIX,DIY
        XOR     A
        OUT     (C),D                   ;DX
        OUT     (C),A
        OUT     (C),E                   ;DY
        OUT     (C),A
        OUT     (C),A                   ;dummy
        OUT     (C),A                   ;dummy
        OUT     (C),L                   ;NY
        OUT     (C),A
        OUT     (C),A                   ;dummy
        POP     AF
        OUT     (C),A                   ;DIX and DIY
        LD      A,11100000B             ;YMMM command
        OUT     (C),A

        EI
        RET

GET.STATUS:
        PUSH    BC
        LD      BC,(WRVDP)
        INC     C
        OUT     (C),A
        LD      A,8FH
        OUT     (C),A
        LD      BC,(RDVDP)
        INC     C
        IN      A,(C)
        POP     BC
        RET

WAIT.VDP:
        LD      A,2
        CALL    GET.STATUS
        AND     1
        JP      NZ,WAIT.VDP
        XOR     A
        CALL    GET.STATUS
        RET

        END

 

6.5.3 HMMM (high-speed transfer between VRAM)

Data of specified VRAM area is transferred into another area in VRAM (see Figure 4.80).

After setting the parameters as shown in Figure 4.81, writing D0H in R#46 causes the command to be executed. While the command is being executed, CE bit of S#2 is “1”. List 4.10 shows an example of using HMMM.

Figure 4.80 Actions of HMMM command
                    VRAM or expansion RAM
----------------------------------------------------------------
|                                                              |
|     (SX,SY)                                                  |
|       ------------------ -->                                 |
|       |       NX       | DIX                                 |
|       |                |                                     |
|       | NY             |                                     |
|       |                |                                     |
|       ------------------  --+                                |
|       | DIY                 |                                |
|       V                     |                                |
|                             |      (DX,DY)                   |
|                             +->  ------------------          |
|                                  |                |          |
|                                  |                |          |
|                                  |                |          |
|                                  |                |          |
|                                  ------------------          |
|                                                              |
----------------------------------------------------------------

MXS: select the source memory           0 = VRAM, 1 = expansion RAM
MXD: select the destination memory      0 = VRAM, 1 = expansion RAM

SX:  source origin X-coordinate (0 to 511)*
SY:  source origin Y-coordinate (0 to 1023)

NX:  number of dots to be transferred in X direction (0 to 511)*
NY:  number of dots to be transferred in Y direction (0 to 1023)

DIX: direction of NX from the origin    0 = right, 1 = left
DIY: direction of NY from the origin    0 = below, 1 = above

DX:  destination origin  X-coordinate (0 to 511)*
DY:  destination origin  Y-coordinate (0 to 1023)

* The one low-order bit for GRAPHIC 4 and 6 modes,
 or two low-order bits for GRAPHIC 5 mode of the SX, DX, and NX register are ignored.
Figure 4.81 Register settings of HMMM command
> HMMM register setup

    MSB   7    6    5    4    3    2    1    0    LSB
        -----------------------------------------
R#32    | SX7| SX6| SX5| SX4| SX3| SX2| SX1| SX0|
        |----+----+----+----+----+----+----+----| SX ---+
R#33    | 0  | 0  | 0  | 0  | 0  | 0  | 0  | SX8|       |
        -----------------------------------------       |
                                                        | source origin
        -----------------------------------------       |
R#34    | SY7| SY6| SY5| SY4| SY3| SY2| SY1| SY0|       |
        |----+----+----+----+----+----+----+----| SY ---+
R#35    | 0  | 0  | 0  | 0  | 0  | 0  | SY9| SY8|
        -----------------------------------------

        -----------------------------------------
R#36    | DX7| DX6| DX5| DX4| DX3| DX2| DX1| DX0|
        |----+----+----+----+----+----+----+----| DX ---+
R#37    | 0  | 0  | 0  | 0  | 0  | 0  | 0  | DX8|       |
        -----------------------------------------       |
                                                        | destination origin
        -----------------------------------------       |
R#38    | DY7| DY6| DY5| DY4| DY3| DY2| DY1| DY0|       |
        |----+----+----+----+----+----+----+----| DY ---+
R#39    | 0  | 0  | 0  | 0  | 0  | 0  | DY9| DY8|
        -----------------------------------------

        -----------------------------------------
R#40    | NX7| NX6| NX5| NX4| NX3| NX2| NX1| NX0|
        |----+----+----+----+----+----+----+----| NX ⟶ Number of dots in X direction to be transferred
R#41    | 0  | 0  | 0  | 0  | 0  | 0  | 0  | NX8|
        -----------------------------------------

        -----------------------------------------
R#42    | NY7| NY6| NY5| NY4| NY3| NY2| NY1| NY0|
        |----+----+----+----+----+----+----+----| NY ⟶ Number of dots in Y direction to be transferred
R#43    | 0  | 0  | 0  | 0  | 0  | 0  | NY9| NY8|
        -----------------------------------------

        -----------------------------------------
R#45    |  0 | -- | MXD| MXS| DIY| DIX| -- | -- | ARG (Argument register)
        -----------------------------------------
                     |    |    |   direction (X)
                     |    |    |
                     |    |    +-> direction (Y)
                     |    |
                     |    +------> select source memory
                     |
                     +-----------> select destination memory

> HMMM command execution

    MSB   7    6    5    4    3    2    1    0    LSB
        -----------------------------------------
R#46    | 1  | 1  | 0  | 1  | -- | -- | -- | -- | CMR
        -----------------------------------------
List 4.10 Example of HMMM command execution
;****************************************************************
;  List 4.10   HMMM sample
;                to use, set H, L, D, E, B, C and go
;                VRAM (H,L)-(D,E) ⟶ VRAM (B,C)
;                DIX must be set in D(bit 2)
;****************************************************************
;
RDVDP:  EQU     0006H
WRVDP:  EQU     0007H

;----- program start -----

HMMM:   DI                              ;disable interrupt
        PUSH    BC                      ;save destination
        CALL    WAIT.VDP                ;wait end of command

        LD      A,(WRVDP)
        LD      C,A
        INC     C                       ;C := PORT#1's address
        LD      A,32
        OUT     (C),A
        LD      A,80H+17
        OUT     (C),A                   ;R#17 := 32

        INC     C
        INC     C                       ;C := PORT#3's address
        XOR     A
        OUT     (C),H                   ;SX
        OUT     (C),A
        OUT     (C),L                   ;SY
        OUT     (C),A

        LD      A,H                     ;make NX and DIX
        SUB     A
        LD      D,00000100B
        JP      NC,HMMM1
        LD      D,00000000B
        NEG
HMMM1:  LD      H,A                     ;H := NX , D := DIX

        LD      A,L                     ;make NY and DIY
        SUB     A
        LD      E,00001000B
        JP      NC,HMMM2
        LD      E,00000000B
        NEG
HMMM2:  LD      L,A                     ;L := NY , E := DIY

        LD      A,D
        OR      E
        POP     DE                      ;restore DX,DY
        PUSH    AF                      ;save DIX,DIY
        XOR     A
        OUT     (C),D                   ;DX
        OUT     (C),A
        OUT     (C),E                   ;DY
        OUT     (C),A
        OUT     (C),H                   ;NX
        OUT     (C),A
        OUT     (C),L                   ;NY
        OUT     (C),A
        OUT     (C),A                   ;dummy
        POP     AF
        OUT     (C),A                   ;DIX and DIY

        LD      A,11010000B             ;HMMM command
        OUT     (C),A

        EI
        RET

GET.STATUS:
        PUSH    BC
        LD      BC,(WRVDP)
        INC     C
        OUT     (C),A
        LD      A,8FH
        OUT     (C),A
        LD      BC,(RDVDP)
        INC     C
        IN      A,(C)
        POP     BC
        RET

WAIT.VDP:
        LD      A,2
        CALL    GET.STATUS
        AND     1
        JP      NZ,WAIT.VDP
        XOR     A
        CALL    GET.STATUS
        RET

        END

 

6.5.4 HMMV (painting the rectangle in high speed)

Each byte of data in the specified VRAM area is painted by the specified colour code (see Figure 4.82)

After setting the parameters as shown in Figure 4.83, writing C0H in R#46 causes the command to be executed. While the command is being executed, the CE bit of S#2 is 1. List 4.11 shows an example of using HMMV.

Figure 4.82 Actions of HMMC command
              VRAM or expansion RAM
---------------------------------------------------
|                                                 |   MSX-VIDEO
|                                                 |    -------
|    (DX,DY)                                      |    |     |
|       x------------------------ --> DIX         |    |     |
|       |          NX           |                 |    |     |
|       | NY                    |<----------------+----|     |
|       |                       |                 |    |     |
|       -------------------------                 |    |     |
|       | DIY                                     |    |     |
|       V                                         |    |     |
|                                                 |    -------
|                                                 |
---------------------------------------------------

MXD: select memory                      0 = VRAM, 1 = expansion RAM

NX:  number of dots to be painted in X direction (0 to 511)*
NY:  number of dots to be painted in Y direction (0 to 1023)

DIX: direction of NX from the origin    0 = right, 1 = left
DIY: direction of NY from the origin    0 = below, 1 = above

DX:  origin  X-coordinate (0 to 511)*
DY:  origin  Y-coordinate (0 to 1023)

CLR (R#44:Colour register):  Painted data

* The one low-order bit for GRAPHIC 4 and 6 modes,
  or two low-order bits for GRAPHIC 5 mode of the DX and NX registers are ignored.
Figure 4.83 Register settings of HMMV command
> HMMV register setup

    MSB   7    6    5    4    3    2    1    0    LSB
        -----------------------------------------
R#36    | DX7| DX6| DX5| DX4| DX3| DX2| DX1| DX0|
        |----+----+----+----+----+----+----+----| DX ---+
R#37    | 0  | 0  | 0  | 0  | 0  | 0  | 0  | DX8|       |
        -----------------------------------------       |
                                                        | origin
        -----------------------------------------       |
R#38    | DY7| DY6| DY5| DY4| DY3| DY2| DY1| DY0|       |
        |----+----+----+----+----+----+----+----| DY ---+
R#39    | 0  | 0  | 0  | 0  | 0  | 0  | DY9| DY8|
        -----------------------------------------

        -----------------------------------------
R#40    | NX7| NX6| NX5| NX4| NX3| NX2| NX1| NX0|
        |----+----+----+----+----+----+----+----| NX ⟶ number of dots in X direction to be painted
R#41    | 0  | 0  | 0  | 0  | 0  | 0  | 0  | NX8|
        -----------------------------------------

        -----------------------------------------
R#42    | NY7| NY6| NY5| NY4| NY3| NY2| NY1| NY0|
        |----+----+----+----+----+----+----+----| NY ⟶ number of dots inY direction to be painted
R#43    | 0  | 0  | 0  | 0  | 0  | 0  | NY9| NY8|
        -----------------------------------------

        -----------------------------------------                     --+
R#44    | CR7| CR6| CR5| CR4| CR3| CR2| CR1| CR0| CLR (GRAPHIC 4,6)     |
        -----------------------------------------                       |
        |                   |                   |                       |
        +-------------------+-------------------+                       |
                X=2N               X=2N+1         (N=0, 1, ..., 127)    |
                                                                        |
        -----------------------------------------                       |
        | CR7| CR6| CR5| CR4| CR3| CR2| CR1| CR0| CLR (GRAPHIC 5)       | data to be painted
        -----------------------------------------                       |
        |         |         |         |         |                       |
        +---------+---------+---------+---------+                       |
           X=4N     X=4N+1    X=4N+2    X=4N+3    (N=0, 1, ..., 127)    |
                                                                        |
        -----------------------------------------                       |
        | CR7| CR6| CR5| CR4| CR3| CR2| CR1| CR0| CLR (GRAPHIC 7)       |
        -----------------------------------------                     --+
                      1 byte / dot                                       

        -----------------------------------------
R#45    |  0 | -- | MXD| -- | DIY| DIX| -- | -- | ARG (Argument register)
        -----------------------------------------
                     |         |   painting direction (X)
                     |         |
                     |         +-> painting direction (Y)
                     |
                     +-----------> memory selection

> HMMV command execution

    MSB   7    6    5    4    3    2    1    0    LSB
        -----------------------------------------
R#46    | 1  | 1  | 0  | 0  | -- | -- | -- | -- | CMR
        -----------------------------------------
List 4.11 Example of HMMV command execution
;****************************************************************
;  List 4.11   HMMV sample
;                to use, set H, L, D, E, B and go
;                B ⟶ VRAM (H,L)-(D,E) fill
;****************************************************************
;
RDVDP:  EQU     0006H
WRVDP:  EQU     0007H

;----- program start -----

HMMV:   DI                              ;disable interrupt
        CALL    WAIT.VDP                ;wait end of command

        LD      A,(WRVDP)
        LD      C,A
        INC     C                       ;C := PORT#1's address
        LD      A,36
        OUT     (C),A
        LD      A,80H+17
        OUT     (C),A                   ;R#17 := 36

        INC     C
        INC     C                       ;C := PORT#3's address
        XOR     A
        OUT     (C),H                   ;DX
        OUT     (C),A
        OUT     (C),L                   ;DY
        OUT     (C),A

        LD      A,H                     ;make NX and DIX
        SUB     A
        LD      D,00000100B
        JP      NC,HMMV1
        LD      D,00000000B
        NEG
HMMV1:  LD      H,A                     ;H := NX

        LD      A,L                     ;make NY and DIY
        SUB     A
        LD      E,00001000B
        JP      NC,HMMV2
        LD      E,00000000B
        NEG
HMMV2:  OUT     (C),H
        LD      H,A                     ;H := NY

        XOR     A
        OUT     (C),A
        OUT     (C),H
        OUT     (C),A
        OUT     (C),B                   ;fill data
        XOR     A
        OR      D
        OR      E
        OUT     (C),A                   ;DIX and DIY

        LD      A,11000000B             ;HMMV command
        OUT     (C),A

        EI
        RET

GET.STATUS:
        PUSH    BC
        LD      BC,(WRVDP)
        INC     C
        OUT     (C),A
        LD      A,8FH
        OUT     (C),A
        LD      BC,(RDVDP)
        INC     C
        IN      A,(C)
        POP     BC
        RET

WAIT.VDP:
        LD      A,2
        CALL    GET.STATUS
        AND     1
        JP      NZ,WAIT.VDP
        XOR     A
        CALL    GET.STATUS
        RET

        END

 

6.5.5 LMMC (CPU -> VRAM logical transfer)

Data is transferred from the CPU to thespecified VRAM area in dots (see Figure 4.84). Logical operations with the source can be specified. In the logical transfer commands, such as LMMC, data is transfered in dots and one byte is required for the information of one pixel in all screen modes.

After setting the data as shown in Figure 4.85, write command code B0H in R#46. At this point, logical operations can be specified by using the 4 low order bits of the command register. Data is transferred with reference to the TR and CE bit of S#2, as in HMMC (see Figure 4.86). List 4.12 shows an example of using LMMC.

Figure 4.84 Action of LMMC command
              VRAM or expansion RAM
---------------------------------------------------
|                                                 |   MSX-VIDEO      CPU
|                                                 |    -------     -------
|    (DX,DY)                                      |    |     |     |     |
|       x------------------------ --> DIX         |    |     |     |     |
|       |          NX           |                 |    |     |     |     |
|       | NY                    |<----------------+----|     |-----|     |
|       |                       |                 |    |     |     |     |
|       -------------------------                 |    |     |     |     |
|       | DIY                                     |    |     |     |     |
|       V                                         |    |     |     |     |
|                                                 |    -------     -------
|                                                 |
---------------------------------------------------

MXD: select destination memory          0 = VRAM, 1 = expansion RAM

NX:  number of dots to be transferred in X direction (0 to 511)
NY:  number of dots to be transferred in Y direction (0 to 1023)

DIX: direction of NX from the origin    0 = right, 1 = left
DIY: direction of NY from the origin    0 = below, 1 = above

DX:  destination origin  X-coordinate (0 to 511)
DY:  destination origin  Y-coordinate (0 to 1023)

CLR (R#44:Colour register):  1st byte of data to be transferred
Figure 4.85 Register settings of LMMC command
> LMMC register setup

    MSB   7    6    5    4    3    2    1    0    LSB
        -----------------------------------------
R#36    | DX7| DX6| DX5| DX4| DX3| DX2| DX1| DX0|
        |----+----+----+----+----+----+----+----| DX ---+
R#37    | 0  | 0  | 0  | 0  | 0  | 0  | 0  | DX8|       |
        -----------------------------------------       |
                                                        | destination origin
        -----------------------------------------       |
R#38    | DY7| DY6| DY5| DY4| DY3| DY2| DY1| DY0|       |
        |----+----+----+----+----+----+----+----| DY ---+
R#39    | 0  | 0  | 0  | 0  | 0  | 0  | DY9| DY8|
        -----------------------------------------

        -----------------------------------------
R#40    | NX7| NX6| NX5| NX4| NX3| NX2| NX1| NX0|
        |----+----+----+----+----+----+----+----| NX ⟶ Number of dots in X direction to be transferred
R#41    | 0  | 0  | 0  | 0  | 0  | 0  | 0  | NX8|
        -----------------------------------------

        -----------------------------------------
R#42    | NY7| NY6| NY5| NY4| NY3| NY2| NY1| NY0|
        |----+----+----+----+----+----+----+----| NY ⟶ Number of dots in Y direction to be transferred
R#43    | 0  | 0  | 0  | 0  | 0  | 0  | NY9| NY8|
        -----------------------------------------

        -----------------------------------------                  --+
R#44    | -- | -- | -- | -- | CR3| CR2| CR1| CR0| CLR (GRAPHIC 4,6)  |
        -----------------------------------------                    |
                                                                     |
        -----------------------------------------                    |
        | -- | -- | -- | -- | -- | -- | CR1| CR0| CLR (GRAPHIC 5)    | data to be transferred
        -----------------------------------------                    |
                                                                     |
        -----------------------------------------                    |
        | CR7| CR6| CR5| CR4| CR3| CR2| CR1| CR0| CLR (GRAPHIC 7)    |
        -----------------------------------------                  --+

        -----------------------------------------
R#45    |  0 | -- | MXD| -- | DIY| DIX| -- | -- | ARG (Argument register)
        -----------------------------------------
                     |         |   direction (X)
                     |         |
                     |         +-> direction (Y)
                     |
                     +-----------> select destination memory

> LMMC command execution

    MSB   7    6    5    4    3    2    1    0    LSB
        -----------------------------------------
R#46    | 1  | 0  | 1  | 1  | L03| L02| L01| L00| CMR
        -----------------------------------------
                            |                   |
                            +-------------------+
                              Logical operation
Figure 4.86 LMMC command execution flow chart
        /-------------------\
        |     LMMC start    |
        \-------------------/
                  |
        ---------------------
        |   register setup  |
        ---------------------
                  |
        ---------------------
        | command execution |
        ---------------------
                  |
+---------------->|
|                 |
|    ---------------------------
|    | read status register #2 |
|    ---------------------------
|                 |
|       //////////+\\\\\\\\\\ Yes (CE bit = 0)
|       |   command end?    |-------------------+
|       \\\\\\\\\\+//////////                   |
|                 | No (CE bit = 1)             |
|       //////////+\\\\\\\\\\                   |
|<------|     transfer?     |                   |
| No    \\\\\\\\\\+//////////                   |
| (TR bit=0)      | Yes (TR bit = 1)            |
|       ---------------------                   |
|       |   transfer data   |                   |
|       ---------------------                   |
|                 |                             |
+-----------------+                             |
                                                |
                  +-----------------------------+
                  |
                  V
        /--------------------\
        |      LMMC end      |
        \--------------------/
List 4.12 Example of LMMC command execution
;****************************************************************
;  List 4.12    LMMC sample
;                 to use, set H, L, D, E, IX, A and go
;                 RAM (IX) ⟶ VRAM (H,L)-(D,E) (logi-OP : A)
;****************************************************************
;
RDVDP:  EQU     0006H
WRVDP:  EQU     0007H

;----- program start -----

LMMC:   DI                              ;disable interrupt
        LD      B,A                     ;B := LOGICAL OPERATION
        CALL    WAIT.VDP                ;wait end of command

        LD      A,(WRVDP)
        LD      C,A
        INC     C                       ;C := PORT#1's address
        LD      A,36
        OUT     (C),A
        LD      A,80H+17
        OUT     (C),A                   ;R#17 := 36

        INC     C
        INC     C                       ;C := PORT#3's address
        XOR     A
        OUT     (C),H                   ;DX
        OUT     (C),A
        OUT     (C),L                   ;DY
        OUT     (C),A

        LD      A,H                     ;make NX and DIX
        SUB     A
        LD      D,00000100B
        JR      NC,LMMC1
        LD      D,00000000B
        NEG
LMMC1:  LD      H,A                     ;H := NX , D := DIX

        LD      A,L
        SUB     A
        LD      E,00001000B
        JR      NC,LMMC2
        LD      E,00000000B
        NEG
LMMC2:  LD      L,A                     ;L := NY , E := DIY

        XOR     A
        OUT     (C),H                   ;NX
        OUT     (C),A
        OUT     (C),L                   ;NY
        OUT     (C),A
        LD      A,(IX+0)
        OUT     (C),A                   ;first DATA
        LD      A,D
        OR      E
        OUT     (C),A                   ;DIX and DIY

        LD      A,B                     ;A := LOGICAL OPERATION
        OR      10110000B               ;LMMC command
        OUT     (C),A

        DEC     C
        DEC     C

LOOP:   LD      A,2
        CALL    GET.STATUS
        BIT     0,A                     ;check CE bit
        JP      Z,EXIT
        BIT     7,A                     ;check TR bit
        JP      Z,LOOP
        INC     IX
        LD      A,(IX+0)
        OUT     (C),A
        JR      LOOP

EXIT:   LD      A,0
        CALL    GET.STATUS

        EI
        RET

GET.STATUS:
        PUSH    BC
        LD      BC,(WRVDP)
        INC     C
        OUT     (C),A
        LD      A,8FH
        OUT     (C),A
        LD      BC,(RDVDP)
        INC     C
        IN      A,(C)
        POP     BC
        RET

WAIT.VDP:
        LD      A,2
        CALL    GET.STATUS
        AND     1
        JR      NZ,WAIT.VDP
        XOR     A
        CALL    GET.STATUS
        RET

        END

 

6.5.6 LMCM (VRAM - CPU logical transfer)

Data is transferred from the specified VRAM area to CPU in dots (see Figure 4.87)

After setting the parameters as shown in Figure 4.88, writing command code A0H in R#46 causes the command to be executed and data to be transferred from MSX-VIDEO. The CPU refers to the TR bit of S#2 and, since data of MSX-VIDEO has been prepared if this bit is “1”, the CPU reads data from S#7. When CE bit of S#2 is “0”, data comes to the end (see Figure 4.89). List 4.13 shows an example of using LMCM.

Figure 4.87 Action of LMCM command
              VRAM or expansion RAM
---------------------------------------------------
|                                                 |   MSX-VIDEO      CPU
|                                                 |    -------     -------
|    (SX,SY)                                      |    |     |     |     |
|       x------------------------ --> DIX         |    |     |     |     |
|       |          NX           |                 |    |     |     |     |
|       | NY                    |-----------------+--->|     |---->|     |
|       |                       |                 |    |     |     |     |
|       -------------------------                 |    |     |     |     |
|       | DIY                                     |    |     |     |     |
|       V                                         |    |     |     |     |
|                                                 |    -------     -------
|                                                 |
---------------------------------------------------

MXS: select source memory               0 = VRAM, 1 = expansion RAM

SX:  source origin  X-coordinate (0 to 511)
SY:  source origin  Y-coordinate (0 to 1023)

NX:  number of dots to be transferred in X direction (0 to 511)
NY:  number of dots to be transferred in Y direction (0 to 1023)

DIX: direction of NX from the origin    0 = right, 1 = left
DIY: direction of NY from the origin    0 = below, 1 = above
Figure 4.88 Register settings of LMCM command
> LMCM register setup

    MSB   7    6    5    4    3    2    1    0    LSB
        -----------------------------------------
R#32    | SX7| SX6| SX5| SX4| SX3| SX2| SX1| SX0|
        |----+----+----+----+----+----+----+----| SX ---+
R#33    | 0  | 0  | 0  | 0  | 0  | 0  | 0  | SX8|       |
        -----------------------------------------       |
                                                        | source origin
        -----------------------------------------       |
R#34    | SY7| SY6| SY5| SY4| SY3| SY2| SY1| SY0|       |
        |----+----+----+----+----+----+----+----| SY ---+
R#35    | 0  | 0  | 0  | 0  | 0  | 0  | SY9| SY8|
        -----------------------------------------

        -----------------------------------------
R#40    | NX7| NX6| NX5| NX4| NX3| NX2| NX1| NX0|
        |----+----+----+----+----+----+----+----| NX ⟶ Number of dots in X direction to be transferred
R#41    | 0  | 0  | 0  | 0  | 0  | 0  | 0  | NX8|
        -----------------------------------------

        -----------------------------------------
R#42    | NY7| NY6| NY5| NY4| NY3| NY2| NY1| NY0|
        |----+----+----+----+----+----+----+----| NY ⟶ Number of dots in Y direction to be transferred
R#43    | 0  | 0  | 0  | 0  | 0  | 0  | NY9| NY8|
        -----------------------------------------

        -----------------------------------------
R#45    |  0 | -- | -- | MXS| DIY| DIX| -- | -- | ARG (Argument register)
        -----------------------------------------
                          |    |   direction (X)
                          |    |
                          |    +-> direction (Y)
                          |
                          +------> select source memory

> LMCM command execution

    MSB   7    6    5    4    3    2    1    0    LSB
        -----------------------------------------
R#46    | 1  | 0  | 1  | 0  | -- | -- | -- | -- | CMR
        -----------------------------------------

        -----------------------------------------
S#7     | 0  | 0  | 0  | 0  | C3 | C2 | C1 | C0 | status register(GRAPHIC4,6)
        -----------------------------------------

        -----------------------------------------
S#7     | 0  | 0  | 0  | 0  | 0  | 0  | C1 | C0 | status register (GRAPHIC 5)
        -----------------------------------------

        -----------------------------------------
S#7     | C7 | C6 | C5 | C4 | C3 | C2 | C1 | C0 | status register (GRAPHIC 7)
        -----------------------------------------
Figure 4.89 LMCM command execution flow chart
        /-------------------\
        |     LMCM start    |
        \-------------------/
                  |
        ---------------------
        |   register setup  |
        ---------------------
                  |
        ---------------------
        | command execution |
        ---------------------
                  |
+---------------->|
|                 |
|    ---------------------------
|    | read status register #2 |
|    ---------------------------
|                 |
|       //////////+\\\\\\\\\\ No (TR bit = 0)
|       |  data prepared?   |-------------------+
|       \\\\\\\\\\+//////////                   |
|                 | Yes (TR bit = 1)            |
|                 |                             |
|    ---------------------------                |
|    | read status register #7 |                |
|    ---------------------------                |
|                 |                             |
|                 |<----------------------------+
|                 |
|       //////////+\\\\\\\\\\
+-------|   command end?    |
  No    \\\\\\\\\\+//////////
  (CE bit=1)      | Yes (CE bit = 0)
                  |
                  V
        /--------------------\
        |      LMCM end      |
        \--------------------/

Note 1: Read status register #7 in “register setup”, since TR bit should be reset before the command execution.

Note 2: Though last data was set in register #7 and TR bit was 1, the command would end inside of the MSX-VIDEO and CE would be zero.

List 4.13 Example of LMCM command execution
;****************************************************************
;  List 4.13   LMCM sample
;                 to use, set H, L, D, E, IX, A and go
;                 VRAM (H,L)-(D,E) ⟶ RAM (IX)
;****************************************************************
;
RDVDP:  EQU     0006H
WRVDP:  EQU     0007H

;----- program start -----

LMCM:   DI                              ;disable interrupt
        LD      B,A                     ;B := LOGICAL OPERATION
        CALL    WAIT.VDP                ;wait end of command

        LD      A,(WRVDP)
        LD      C,A
        INC     C                       ;C := PORT#1's address
        LD      A,32
        OUT     (C),A
        LD      A,80H+17
        OUT     (C),A                   ;R#17 := 32
        INC     C
        INC     C                       ;C := PORT#3's address
        XOR     A
        OUT     (C),H                   ;SX
        OUT     (C),A
        OUT     (C),L                   ;SY
        OUT     (C),A
        OUT     (C),A                   ;dummy
        OUT     (C),A                   ;dummy
        OUT     (C),A                   ;dummy
        OUT     (C),A                   ;dummy
        LD      A,H                     ;make NX and DIX
        SUB     A
        LD      D,00000100B
        JR      NC,LMCM1
        LD      D,00000000B
        NEG
LMCM1:  LD      H,A                     ;H := NX , D := DIX

        LD      A,L
        SUB     A
        LD      E,00001000B
        JR      NC,LMCM2
        LD      E,00000000B
        NEG
LMCM2:  LD      L,A                     ;L := NY , E := DIY

        XOR     A
        OUT     (C),H                   ;NX
        OUT     (C),A
        OUT     (C),L                   ;NY
        OUT     (C),A
        LD      A,(IX+0)
        OUT     (C),A                   ;dummy
        LD      A,D
        OR      E
        OUT     (C),A                   ;DIX and DIY
        LD      A,7
        CALL    GET.STATUS
        LD      A,B                     ;A := LOGICAL OPERATION
        OR      10100000B               ;LMCM command
        OUT     (C),A
        LD      A,(RDVDP)
        LD      C,A                     ;C := PORT#1's address
LOOP:   LD      A,2
        CALL    GET.STATUS
        BIT     0,A                     ;check CE bit
        JP      Z,EXIT
        BIT     7,A                     ;check TR bit
        JP      Z,LOOP
        LD      A,7
        CALL    GET.STATUS
        LD      (IX+0),A
        INC     IX
        JR      LOOP

EXIT:   LD      A,0
        CALL    GET.STATUS
        EI
        RET

GET.STATUS:
        PUSH    BC
        LD      BC,(WRVDP)
        INC     C
        OUT     (C),A
        LD      A,8FH
        OUT     (C),A
        LD      BC,(RDVDP)
        INC     C
        IN      A,(C)
        POP     BC
        RET

WAIT.VDP:
        LD      A,2
        CALL    GET.STATUS
        AND     1
        JR      NZ,WAIT.VDP
        XOR     A
        CALL    GET.STATUS
        RET

        END

 

6.5.7. LMMM (VRAM->VRAM logical transfer)

Data of the specified VRAM area is transferred into another VRAM area in dots (see figure 4.9)

After setting the parameters as shown in Figure 4.91, writing command code 9XH (X means a logical operation) in R#46 causes the command to be executed. While the CE bit of S#2 is “1”, the command is being executed. List 4.14 shows an example of using LMMM.

Figure 4.90 Actions of LMMM command
                    VRAM or expansion RAM
----------------------------------------------------------------
|                                                              |
|     (SX,SY)                                                  |
|       ------------------ -->                                 |
|       |       NX       | DIX                                 |
|       |                |                                     |
|       | NY             |                                     |
|       |                |                                     |
|       ------------------  --+                                |
|       | DIY                 |                                |
|       V                     |                                |
|                             |      (DX,DY)                   |
|                             +->  ------------------          |
|                                  |                |          |
|                                  |                |          |
|                                  |                |          |
|                                  |                |          |
|                                  ------------------          |
|                                                              |
----------------------------------------------------------------

MXS: select the source memory           0 = VRAM, 1 = expansion RAM
MXD: select the destination memory      0 = VRAM, 1 = expansion RAM

SX:  source origin X-coordinate (0 to 511)
SY:  source origin Y-coordinate (0 to 1023)

NX:  number of dots to be transferred in X direction (0 to 511)
NY:  number of dots to be transferred in Y direction (0 to 1023)

DIX: direction of NX from the origin    0 = right, 1 = left
DIY: direction of NY from the origin    0 = below, 1 = above

DX:  destination origin  X-coordinate (0 to 511)
DY:  destination origin  Y-coordinate (0 to 1023)
Figure 4.91 Register settings of LMMM command
> LMMM register setup

    MSB   7    6    5    4    3    2    1    0    LSB
        -----------------------------------------
R#32    | SX7| SX6| SX5| SX4| SX3| SX2| SX1| SX0|
        |----+----+----+----+----+----+----+----| SX ---+
R#33    | 0  | 0  | 0  | 0  | 0  | 0  | 0  | SX8|       |
        -----------------------------------------       |
                                                        | source origin
        -----------------------------------------       |
R#34    | SY7| SY6| SY5| SY4| SY3| SY2| SY1| SY0|       |
        |----+----+----+----+----+----+----+----| SY ---+
R#35    | 0  | 0  | 0  | 0  | 0  | 0  | SY9| SY8|

        -----------------------------------------

        -----------------------------------------
R#36    | DX7| DX6| DX5| DX4| DX3| DX2| DX1| DX0|
        |----+----+----+----+----+----+----+----| DX ---+
R#37    | 0  | 0  | 0  | 0  | 0  | 0  | 0  | DX8|       |
        -----------------------------------------       |
                                                        | destination origin
        -----------------------------------------       |
R#38    | DY7| DY6| DY5| DY4| DY3| DY2| DY1| DY0|       |
        |----+----+----+----+----+----+----+----| DY ---+
R#39    | 0  | 0  | 0  | 0  | 0  | 0  | DY9| DY8|
        -----------------------------------------

        -----------------------------------------
R#40    | NX7| NX6| NX5| NX4| NX3| NX2| NX1| NX0|         Number of dots in
        |----+----+----+----+----+----+----+----| NX ⟶ X direction to be
R#41    | 0  | 0  | 0  | 0  | 0  | 0  | 0  | NX8|         transferred
        -----------------------------------------

        -----------------------------------------
R#42    | NY7| NY6| NY5| NY4| NY3| NY2| NY1| NY0|         Number of dots in
        |----+----+----+----+----+----+----+----| NY ⟶ Y direction to be
R#43    | 0  | 0  | 0  | 0  | 0  | 0  | NY9| NY8|         transferred
        -----------------------------------------

        -----------------------------------------
R#45    |  0 | -- | MXD| MXS| DIY| DIX| -- | -- | ARG (Argument register)
        -----------------------------------------
                     |    |    |   direction (X)
                     |    |    |
                     |    |    +-> direction (Y)
                     |    |
                     |    +------> select source memory
                     |
                     +-----------> select destination memory

> LMMM command execution

    MSB   7    6    5    4    3    2    1    0    LSB
        -----------------------------------------
R#46    | 1  | 0  | 0  | 1  | L03| L02| L01| L00| CMR
        -----------------------------------------
                            |                   |
                            +-------------------+
                              Logical operation
List 4.14 Example of LMMM command execution
;****************************************************************
;  List 4.14   LMMM sample
;                to use, set H, L, D, E, B, C, A and go
;                VRAM (H,L)-(D,E) ⟶ VRAM (B,C) (logi-OP : A)
;****************************************************************
;
RDVDP:  EQU     0006H
WRVDP:  EQU     0007H

;----- program start -----

LMMM:   DI                              ;disable interrupt
        PUSH    AF                      ;save LOGICAL OPERATION
        PUSH    BC                      ;save DESTINATION
        CALL    WAIT.VDP                ;wait end of command

        LD      A,(WRVDP)
        LD      C,A
        INC     C                       ;C := PORT#1's address
        LD      A,32
        OUT     (C),A
        LD      A,80H+17
        OUT     (C),A                   ;R#17 := 32

        INC     C
        INC     C                       ;C := PORT#3's address
        XOR     A
        OUT     (C),H                   ;SX
        OUT     (C),A
        OUT     (C),L                   ;SY
        OUT     (C),A

        LD      A,H                     ;make NX and DIX
        SUB     A
        LD      D,00000100B
        JP      NC,LMMM1
        LD      D,00000000B
        NEG
LMMM1:  LD      H,A                     ;H := NX , D := DIX

        LD      A,L                     ;make NY and DIY
        SUB     A
        LD      E,00001000B
        JP      NC,LMMM2
        LD      E,00000000B
        NEG
LMMM2:  LD      L,A                     ;L := NY , E := DIY

        LD      A,D
        OR      E
        POP     DE                      ;restore DX,DY
        PUSH    AF                      ;save DIX,DIY
        XOR     A
        OUT     (C),D                   ;DX
        OUT     (C),A
        OUT     (C),E                   ;DY
        OUT     (C),A
        OUT     (C),H                   ;NX
        OUT     (C),A
        OUT     (C),L                   ;NY
        OUT     (C),A
        OUT     (C),A                   ;dummy
        POP     AF
        OUT     (C),A                   ;DIX and DIY

        POP     AF                      ;A := LOGICAL OPERATION
        OR      10010000B               ;LMMM command
        OUT     (C),A

        EI
        RET

GET.STATUS:
        PUSH    BC
        LD      BC,(WRVDP)
        INC     C
        OUT     (C),A
        LD      A,8FH
        OUT     (C),A
        LD      BC,(RDVDP)
        INC     C
        IN      A,(C)
        POP     BC
        RET

WAIT.VDP:
        LD      A,2
        CALL    GET.STATUS
        AND     1
        JP      NZ,WAIT.VDP
        XOR     A
        CALL    GET.STATUS
        RET

        END

 

6.5.8 LMMV (VRAM logical paint)

The specified VRAM area is painted by the colour code in dots (see Figure 4.92). Logical operations between data in VRAM and the specified data are allowed.

After setting the parameters as shown in Figure 4.93, writing command code 8Xh (X means a logical operation) in R#46 causes the command to be executed. While the CE bit of S#2 is “1”, the command is being executed. List 4.15 shows an example of using LMMV.

Figure 4.92 Actions of LMMV command
              VRAM or expansion RAM
---------------------------------------------------
|                                                 |   MSX-VIDEO
|                                                 |    -------
|    (DX,DY)                                      |    |     |
|       x------------------------ --> DIX         |    |     |
|       |          NX           |                 |    |     |
|       | NY                    |<----------------+----|     |
|       |                       |                 |    |     |
|       -------------------------                 |    |     |
|       | DIY                                     |    |     |
|       V                                         |    |     |
|                                                 |    -------
|                                                 |
---------------------------------------------------

MXD: select memory                      0 = VRAM, 1 = expansion RAM

NX:  number of dots to be painted in X direction (0 to 511)
NY:  number of dots to be painted in Y direction (0 to 1023)

DIX: direction of NX from the origin    0 = right, 1 = left
DIY: direction of NY from the origin    0 = below, 1 = above

DX:  origin  X-coordinate (0 to 511)
DY:  origin  Y-coordinate (0 to 1023)

CLR (R#44:Colour register):  Painted data
Figure 4.93 Register settings of LMMV command
> LMMV register setup

    MSB   7    6    5    4    3    2    1    0    LSB
        -----------------------------------------
R#36    | DX7| DX6| DX5| DX4| DX3| DX2| DX1| DX0|
        |----+----+----+----+----+----+----+----| DX ---+
R#37    | 0  | 0  | 0  | 0  | 0  | 0  | 0  | DX8|       |
        -----------------------------------------       |
                                                        | origin
        -----------------------------------------       |
R#38    | DY7| DY6| DY5| DY4| DY3| DY2| DY1| DY0|       |
        |----+----+----+----+----+----+----+----| DY ---+
R#39    | 0  | 0  | 0  | 0  | 0  | 0  | DY9| DY8|
        -----------------------------------------

        -----------------------------------------
R#40    | NX7| NX6| NX5| NX4| NX3| NX2| NX1| NX0|
        |----+----+----+----+----+----+----+----| NX ⟶ number of dots in X direction to be painted
R#41    | 0  | 0  | 0  | 0  | 0  | 0  | 0  | NX8|
        -----------------------------------------

        -----------------------------------------
R#42    | NY7| NY6| NY5| NY4| NY3| NY2| NY1| NY0|
        |----+----+----+----+----+----+----+----| NY ⟶ number of dots in Y direction to be painted
R#43    | 0  | 0  | 0  | 0  | 0  | 0  | NY9| NY8|
        -----------------------------------------

        -----------------------------------------                     --+
R#44    | 0  | 0  | 0  | 0  | CR3| CR2| CR1| CR0| CLR (GRAPHIC 4,6)     |
        -----------------------------------------                       |
                                                                        |
        -----------------------------------------                       |
        | 0  | 0  | 0  | 0  | 0  | 0  | CR1| CR0| CLR (GRAPHIC 5)       | data to be transferred
        -----------------------------------------                       |
                                                                        |
        -----------------------------------------                       |
        | CR7| CR6| CR5| CR4| CR3| CR2| CR1| CR0| CLR (GRAPHIC 7)       |
        -----------------------------------------                     --+

        -----------------------------------------
R#45    |  0 | -- | MXD| -- | DIY| DIX| -- | -- | ARG (Argument register)
        -----------------------------------------
                     |         |   painting direction (X)
                     |         |
                     |         +-> painting direction (Y)
                     |
                     +-----------> memory selection

> LMMV command execution

    MSB   7    6    5    4    3    2    1    0    LSB
        -----------------------------------------
R#46    | 1  | 0  | 0  | 0  | L03| L03| L01| L00| CMR
        -----------------------------------------
                            |                   |
                            +-------------------+
                              Logical operation
List 4.15 Example of LMMV command execution
;****************************************************************
;  List 4.15   LMMV sample
;                to use, set H, L, D, E, B, A and go
;                data B ⟶ fill VRAM (H,L)-(D,E) (logi-op : A)
;****************************************************************
;
RDVDP:  EQU     0006H
WRVDP:  EQU     0007H

;----- program start -----

LMMV:   DI                              ;disable interrupt
        PUSH    AF                      ;save LOGICAL OPERATION
        PUSH    BC                      ;save FILL DATA
        CALL    WAIT.VDP                ;wait end of command

        LD      A,(WRVDP)
        LD      C,A
        INC     C                       ;C := PORT#1's address
        LD      A,36
        OUT     (C),A
        LD      A,80H+17
        OUT     (C),A                   ;R#17 := 36

        INC     C
        INC     C                       ;C := PORT#3's address
        XOR     A
        OUT     (C),H                   ;DX
        OUT     (C),A
        OUT     (C),L                   ;DY
        OUT     (C),A

        LD      A,H                     ;make NX and DIX
        SUB     A
        LD      D,00000100B
        JP      NC,LMMV1
        LD      D,00000000B
        NEG
LMMV1:  LD      H,A                     ;H := NX , D := DIX

        LD      A,L                     ;make NY and DIY
        SUB     A
        LD      E,00001000B
        JP      NC,LMMV2
        LD      E,00000000B
        NEG
LMMV2:  LD      L,A                     ;L := NY , E := DIY

        XOR     A
        OUT     (C),H                   ;NX
        OUT     (C),A
        OUT     (C),L                   ;NY
        OUT     (C),A
        POP     AF
        OUT     (C),A                   ;FILL DATA
        LD      A,D
        OR      E
        OUT     (C),A                   ;DIX and DIY

        POP     AF                      ;restore LOGICAL OPERATION
        OR      A,10000000B             ;LMMV command
        OUT     (C),A

        EI
        RET

GET.STATUS:
        PUSH    BC
        LD      BC,(WRVDP)
        INC     C
        OUT     (C),A
        LD      A,8FH
        OUT     (C),A
        LD      BC,(RDVDP)
        INC     C
        IN      A,(C)
        POP     BC
        RET

WAIT.VDP:
        LD      A,2
        CALL    GET.STATUS
        AND     1
        JP      NZ,WAIT.VDP
        XOR     A
        CALL    GET.STATUS
        RET

        END

 

6.5.9 LINE (drawing a line)

Lines can be drawn between any coordinates in VRAM. The parameters to be specified include the (X,Y) coordinates of the starting point and the X and Y lengths in units to the ending point (see Figure 4.94). Logical operations between data in VRAM and the specified data are allowed.

After setting the parameters as shown in Figure 4.94, writing command code 7XH (X means a logical operation) in R#46 causes the command to be executed. While the CE bit of S#2 is “1”, the command is being executed. List 4.16 shows an example of using LINE.

Figure 4.94 Actions of LINE command
              VRAM or expansion RAM
---------------------------------------------------
|                                                 |
|                           / :  ^                |
|                         /   :  |                |
|                       /     : DIY               |
|                     /       :                   |
|                   /     Min :                   |
|                 /           :                   |
|               /             :                   |
|             /     Maj       :                   |
|            x................. -> DIX            |
|         (DX,DY)                                 |
|                                                 |
---------------------------------------------------

MXD: select memory                      0 = VRAM, 1 = expansion RAM

Maj: number of dots of major side (0 to 1023)
Maj: number of dots of minor side (0 to 512)

MAJ: 0 = The major side is parallel to X axis
MAJ: 1 = The major side is parallel to Y axis,
         or the major side = the minor side

DIX: direction of the end from the origin    0 = right, 1 = left
DIY: direction of the end from the origin    0 = below, 1 = above

DX:  origin  X-coordinate (0 to 511)
DY:  origin  Y-coordinate (0 to 1023)

CLR (R#44:Colour register):  Line colour data
Figure 4.95 Register settings of LINE command
> LINE register setup

    MSB   7    6    5    4    3    2    1    0    LSB
        -----------------------------------------
R#36    | DX7| DX6| DX5| DX4| DX3| DX2| DX1| DX0|
        |----+----+----+----+----+----+----+----| DX ---+
R#37    | 0  | 0  | 0  | 0  | 0  | 0  | 0  | DX8|       |
        -----------------------------------------       |
                                                        | origin
        -----------------------------------------       |
R#38    | DY7| DY6| DY5| DY4| DY3| DY2| DY1| DY0|       |
        |----+----+----+----+----+----+----+----| DY ---+
R#39    | 0  | 0  | 0  | 0  | 0  | 0  | DY9| DY8|
        -----------------------------------------

        -----------------------------------------
R#40    | NX7| NX6| NX5| NX4| NX3| NX2| NX1| NX0|
        |----+----+----+----+----+----+----+----| Maj (NX) -> number of dots of the major side
R#41    | 0  | 0  | 0  | 0  | 0  | 0  | 0  | NX8|
        -----------------------------------------

        -----------------------------------------
R#42    | NY7| NY6| NY5| NY4| NY3| NY2| NY1| NY0|
        |----+----+----+----+----+----+----+----| Min (NY) -> number of dots of the minor side
R#43    | 0  | 0  | 0  | 0  | 0  | 0  | NY9| NY8|
        -----------------------------------------

        -----------------------------------------                     --+
R#44    | 0  | 0  | 0  | 0  | CR3| CR2| CR1| CR0| CLR (GRAPHIC 4,6)     |
        -----------------------------------------                       |
                                                                        |
        -----------------------------------------                       |
        | 0  | 0  | 0  | 0  | 0  | 0  | CR1| CR0| CLR (GRAPHIC 5)       | colour code data
        -----------------------------------------                       |
                                                                        |
        -----------------------------------------                       |
        | CR7| CR6| CR5| CR4| CR3| CR2| CR1| CR0| CLR (GRAPHIC 7)       |
        -----------------------------------------                     --+

        -----------------------------------------
R#45    |  0 | -- | MXD| -- | DIY| DIX| -- | MAJ| ARG (Argument register)
        -----------------------------------------
                     |         |    |        major side selection
                     |         |    V
                     |         |   direction to the end (X)
                     |         |
                     |         +-> direction to the end (Y)
                     |
                     +-----------> memory selection

> LINE command execution

    MSB   7    6    5    4    3    2    1    0    LSB
        -----------------------------------------
R#46    | 0  | 1  | 1  | 1  | L03| L03| L01| L00| CMR
        -----------------------------------------
                            |                   |
                            +-------------------+
                              Logical operation
List 4.16 Example of LINE command execution
;****************************************************************
;  List 4.16   LINE sample
;                to use, set H, L, D, E, B, A and go
;                draw LINE (H,L)-(D,E) with color B, log-op A
;****************************************************************
;
RDVDP:  EQU     0006H
WRVDP:  EQU     0007H

;----- program start -----

LINE:   DI                              ;disable interrupt
        PUSH    AF                      ;save LOGICAL OPERATION
        PUSH    BC                      ;save COLOR
        CALL    WAIT.VDP                ;wait end of command
        LD      A,(WRVDP)
        LD      C,A
        INC     C                       ;C := PORT#1's address
        LD      A,36
        OUT     (C),A
        LD      A,80H+17
        OUT     (C),A                   ;R#17 := 36

        INC     C
        INC     C                       ;C := PORT#3's address
        XOR     A
        OUT     (C),H                   ;DX
        OUT     (C),A
        OUT     (C),L                   ;DY
        OUT     (C),A

        LD      A,H                     ;make DX and DIX
        SUB     D
        LD      D,00000100B
        JP      NC,LINE1
        LD      D,00000000B
        NEG
LINE1:  LD      H,A                     ;H := DX , D := DIX

        LD      A,L                     ;make DY and DIY
        SUB     E
        LD      E,00001000B
        JP      NC,LINE2
        LD      E,00000000B
        NEG
LINE2:  LD      L,A                     ;L := DY , E := DIY

        CP      H                       ;make Maj and Min
        JP      C,LINE3
        XOR     A
        OUT     (C),L                   ;long side
        OUT     (C),A
        OUT     (C),H                   ;short side
        OUT     (C),A
        LD      A,00000001B             ;MAJ := 1
        JP      LINE4

LINE3:  XOR     A
        OUT     (C),H                   ;NX
        OUT     (C),A
        OUT     (C),L                   ;NY
        OUT     (C),A
        LD      A,00000000B             ;MAJ := 0

LINE4:  OR      D
        OR      E                       ;A := DIX , DIY , MAJ
        POP     HL                      ;H := COLOR
        OUT     (C),H
        OUT     (C),A
        POP     AF                      ;A := LOGICAL OPERATION
        OR      01110000B
        OUT     (C),A
        LD      A,8FH
        OUT     (C),A
        EI
        RET

GET.STATUS:
        PUSH    BC
        LD      BC,(WRVDP)
        INC     C
        OUT     (C),A
        LD      A,8FH
        OUT     (C),A
        LD      BC,(RDVDP)
        INC     C
        IN      A,(C)
        POP     BC
        RET

WAIT.VDP:
        LD      A,2
        CALL    GET.STATUS
        AND     1
        JP      NZ,WAIT.VDP
        XOR     A
        CALL    GET.STATUS
        RET

        END

 

SRCH searches for the existence of the specified colour from any coordinate on VRAM to the right or the left (see figure 4.96). This is very useful for paint routines.

After setting the parameters as shown in Figure 4.97, writing 60H in R#46 causes the command to be executed. The command terminates when the objective colour is found or when it cannot be found after searching for it to the screen edge. While the CE bit of S#2 is “1”, the command is being executed (see Figure 4.98).

After the command ends, the objective colour code is stored in S#8 and S#9. List 4.17 shows an example of using SRCH.

Figure 4.96 Actions of SRCH command
              VRAM or expansion RAM
---------------------------------------------------
|                                                 |
|                                                 |
|                                                 |
|                                                 |
|           (SX,SY)      DIX                      |
|              x......................>x          |
|                                   Border        |
|                                   colour        |
|                                   point         |
|                                                 |
|                                                 |
|                                                 |
---------------------------------------------------

MXD: memory selection for the seacrh    0 = VRAM, 1 = expansion RAM

SX: search origin X-coordinate (0 to 511)
SY: search origin Y-coordinate (0 to 1023)

DIX: direction for the search from the origin    0 = right, 1 = left

EQ:  0 = ends the execution when the border colour is found
     1 = ends the execution when the colour is found other than the
         border colour

CLR (R#44:Colour register):  border colour
Figure 4.97 Register settings of SRCH command
> SRCH register setup

    MSB   7    6    5    4    3    2    1    0    LSB
        -----------------------------------------
R#32    | SX7| SX6| SX5| SX4| SX3| SX2| SX1| SX0|
        |----+----+----+----+----+----+----+----| SX ---+
R#33    | 0  | 0  | 0  | 0  | 0  | 0  | 0  | SX8|       |
        -----------------------------------------       |
                                                        | search origin
        -----------------------------------------       |
R#34    | SY7| SY6| SY5| SY4| SY3| SY2| SY1| SY0|       |
        |----+----+----+----+----+----+----+----| SY ---+
R#35    | 0  | 0  | 0  | 0  | 0  | 0  | SY9| SY8|
        -----------------------------------------

        -----------------------------------------                     --+
R#44    | 0  | 0  | 0  | 0  | CR3| CR2| CR1| CR0| CLR (GRAPHIC 4,6)     |
        -----------------------------------------                       |
                                                                        |
        -----------------------------------------                       |
        | 0  | 0  | 0  | 0  | 0  | 0  | CR1| CR0| CLR (GRAPHIC 5)       | border colour
        -----------------------------------------                       |
                                                                        |
        -----------------------------------------                       |
        | CR7| CR6| CR5| CR4| CR3| CR2| CR1| CR0| CLR (GRAPHIC 7)       |
        -----------------------------------------                     --+

        -----------------------------------------
R#45    | -- | -- | MXD| -- | -- | DIX| EQ | -- | ARG (Argument register)
        -----------------------------------------
                     |              |   the condition for terminating
                     |              |   the execution
                     |              V
                     |             search direction (X)
                     |
                     +-----------> memory selection for the search

> SRCH command execution

    MSB   7    6    5    4    3    2    1    0    LSB
        -----------------------------------------
R#46    | 0  | 1  | 1  | 0  | -- | -- | -- | -- | CMR
        -----------------------------------------

        -----------------------------------------
S#2     | -- | -- | -- | BO | -- | -- | -- | CE | CMR
        -----------------------------------------
                         |                   when the command ends : 0
                         |
                         +-------> when the border colour is found : 1

        -----------------------------------------
S#8     | BX7| BX6| BX5| BX4| BX3| BX2| BX1| BX0|
        ----------------------------------------- X-coordinate when the border colour is found
S#9     | 1  | 1  | 1  | 1  | 1  | 1  | 1  | BX8|
        -----------------------------------------
Figure 4.98 SRCH command execution flowchart
        /-------------------\
        |     SRCH start    |
        \-------------------/
                  |
        ---------------------
        |   register setup  |
        ---------------------
                  |
        ---------------------
        | command execution |
        ---------------------
                  |
+---------------->|
|                 |
|    ---------------------------
|    | Read status register #2 |
|    ---------------------------
|                 |
|       //////////+\\\\\\\\\\
+-------|   command end?    |
   No   \\\\\\\\\\+//////////
(CE bit = 1)      |
                  | Yes (CE bit = 0)
                  |
     /////////////+\\\\\\\\\\\\\
+----| Is border colour found? |
|    \\\\\\\\\\\\\+/////////////
| No              |
| (BO bit = 0)    | Yes (BO bit = 1)
|                 |
|    ---------------------------
|    | Read status register #8 |
|    ---------------------------
|                 |
|    ---------------------------
|    | Read status register #2 |
|    ---------------------------
|                 |
+---------------->|
                  |
                  V
        /--------------------\
        |      SRCH end      |
        \--------------------/
List 4.17 Example of SRCH command execution
;****************************************************************
;  List 4.17   SRCH sample
;                to use, set H, L, E, A as follows
;                srch (x:H, y:L, color:E, arg(reg#45) : A)
;                returns: Z  (not found)
;                         NZ (A := X)
;****************************************************************
;
RDVDP:  EQU     0006H
WRVDP:  EQU     0007H

;----- program start -----

SRCH:   DI                              ;disable interrupt
        PUSH    AF                      ;save arg
        CALL    WAIT.VDP

        LD      A,(WRVDP)
        LD      C,A
        INC     C                       ;C := PORT#1's address

        LD      D,0
        LD      A,32+80H
        OUT     (C),H
        OUT     (C),A                   ;R#32 := H
        INC     A
        OUT     (C),D
        OUT     (C),A                   ;R#33 := 0
        INC     A
        OUT     (C),L
        OUT     (C),A                   ;R#34 := L
        INC     A
        OUT     (C),D
        OUT     (C),A                   ;R#35 := 0
        LD      A,44+80H
        OUT     (C),E
        OUT     (C),A                   ;R#44 := E
        INC     A
        LD      E,A
        POP     AF                      ;A := ARG
        OUT     (C),A
        OUT     (C),E                   ;R#45 := A

        LD      A,01100000B
        OUT     (C),A
        INC     E
        OUT     (C),E                   ;R#46 := SRCH command

LOOP:   LD      A,2
        CALL    GET.STATUS
        BIT     0,A
        JP      NZ,LOOP
        LD      E,A
        LD      A,8
        CALL    GET.STATUS
        LD      D,A
        LD      A,9
        CALL    GET.STATUS
        LD      A,D
        BIT     4,E

        EI
        RET

GET.STATUS:
        PUSH    BC
        LD      BC,(WRVDP)
        INC     C
        OUT     (C),A
        LD      A,8FH
        OUT     (C),A
        LD      BC,(RDVDP)
        INC     C
        IN      A,(C)
        POP     BC
        RET

WAIT.VDP:
        LD      A,2
        CALL    GET.STATUS
        AND     1
        JP      NZ,WAIT.VDP
        XOR     A
        CALL    GET.STATUS
        RET

        END
List 4.18 Simple PAINT routine using SRCH and LINE
;****************************************************************
;  List 4.18   SRCH and LINE sample
;                search color to right and left,
;                then draw line between the two points
;****************************************************************
;
        EXTRN   SRCH
        EXTRN   LINE

Y       EQU     0A800H
X       EQU     0A801H
COL     EQU     0A802H
ARG     EQU     0A803H
PCOL    EQU     0A804H

;----- program start -----

MAIN:   LD      (STK),SP
        LD      SP,AREA
        LD      HL,(Y)
        LD      A,(COL)
        LD      E,A
        LD      A,(ARG)
        PUSH    HL
        PUSH    DE
        SET     2,A
        CALL    SRCH
        POP     DE
        POP     HL
        JP      NZ,S1
        LD      A,(X)
        DEC     A
S1:     INC     A
        PUSH    AF
        LD      A,(ARG)
        RES     2,A
        CALL    SRCH
        JP      NZ,S2
        LD      A,(X)
        INC     A
S2:     DEC     A
        LD      D,A
        POP     AF
        LD      H,A
        LD      A,(Y)
        LD      L,A
        LD      E,A
        LD      A,(PCOL)
        LD      B,A
        LD      A,0                     ;PSET
        CALL    LINE
        LD      SP,(STK)
        RET

;----- work area -----

STK:    DS      2
        DS      200
AREA:   $

        END
List 4.19 Example of the use of simple PAINT routine
1000 '***********************************************
1010 ' List 4.19   SRCH and LINE sample
1020 ' Operate cursor while holding down the space bar.
1030 '***********************************************
1040 '
1050 SCREEN 5
1060 FOR I=0 TO 50:LINE -(RND(1)*255,RND(1)*211),15:NEXT
1070 I=&HA000 :DEF USR=I
1080 READ A$
1090 IF  A$="END" THEN 1130
1100   POKE I,VAL("&H"+A$):I=I+1
1110   READ A$
1120 GOTO 1090
1130 X=128:Y=100:COL=15:PCOL=2:ARG=0
1140 CURS=0
1150 A=STICK(0)
1160 CURS=(CURS+1) AND 1
1170 LINE (X-5,I)-(X+5,I),15,,XOR
1180 LINE (X,Y-5)-(X,Y+5),15,,XOR
1190 IF CURS=1 THEN 1290
1200 IF A=1 THEN Y=Y-1
1210 IF A=2 THEN Y=Y-1:X=X+1
1220 IF A=3 THEN X=X+1
1230 IF A=4 THEN X=X+1:Y=Y+1
1240 IF A=5 THEN Y=Y+1
1250 IF A=6 THEN Y=Y+1:X=X-1
1260 IF A=7 THEN X=X-1
1270 IF A=8 THEN X=X-1:Y=Y-1
1280 IF STRIG(9) THEN GOSUB 1300
1290 GOTO 1150
1300 POKE &HA800,Y
1310 POKE &HA801,X
1320 POKE &HA802,COL
1330 POKE &HA803,ARG
1340 POKE &HA804,PCOL
1350 A=USR(0)
1360 RETURN
1370 DATA ED,73,80,A8,31,4A,A9,2A,00,A8,3A,02
1380 DATA A8,5F,3A,03,A8,E5,D5,CB,D7,CD,AD
1390 DATA A0,D1,E1,C2,21,A0,3A,01,A8
1400 DATA 3D,3C,F5,3A,03,A8,CB,97,CD,AD,A0,C2
1410 DATA 32,A0,3A,01,AB,3C,3D,57,F1,67,3A
1420 DATA 00,A8,6F,5F,3A,04,A8,47,3E
1430 DATA 00,CD,49,A0,ED,7B,80,A8,C9,F3,F5,CD
1440 DATA 0D,A1,C5,3A,06,00,4F,0C,3E,24,ED
1450 DATA 79,3E,91,ED,79,0C,0C,AF,ED
1460 DATA 61,ED,79,ED,69,ED,79,7C,92,16,04,D2
1470 DATA 72,A0,16,00,ED,44,67,7D,93,1E,08
1480 DATA D2,7E,A0,1E,00,ED,44,BC,DA
1490 DATA 90,A0,ED,79,AF,ED,79,ED,61,ED,79,26
1500 DATA 01,C3,9C,A0,ED,61,67,AF,ED,79,ED
1510 DATA 61,ED,79,26,00,7C,B2,B3,E1
1520 DATA ED,61,ED,79,F1,E6,0F,F6,70,ED,79,FB
1530 DATA C9,F5,F3,CD,0D,A1,ED,4B,06,00,0C
1540 DATA 3E,A0,16,00,ED,61,ED,79,3C
1550 DATA ED,51,ED,79,3C,ED,69,ED,79,3C,ED,51
1560 DATA ED,79,3E,AC,ED,59,ED,79,3C,5F,F1
1570 DATA ED,79,ED,59,3E,60,ED,79,1C
1580 DATA ED,59,3E,02,CD,FD,A0,CB,47,C2,E2,A0
1590 DATA 5F,3E,08,CD,FD,A0,57,3E,00,CD,FD
1600 DATA A0,7A,CB,63,FB,C9,C5,ED,4B
1610 DATA 06,00,0C,ED,79,3E,8F,ED,79,ED,78,C1
1620 DATA C9,3E,02,CD,FD,A0,E6,01,C2,0D,A1
1630 DATA AF,CD,FD,A0,C9,END

 

6.5.11 PSET (drawing a point)

A point is drawn at any coordinate in VRAM (see figure 4.99).

After setting the parameters as shown in Figure 4.100, writing 5XH (X means a logical operation) in R#46 causes the command to be executed. While the CE bit of S#2 is “1”, the command is being executed. List 4.20 shows an example of using PSET.

Figure 4.99 Actions of PSET command
              VRAM or expansion RAM
---------------------------------------------------
|                                                 |
|                                                 |
|                                                 |
|                                                 |
|              (DX,DY)                            |
|                 x                               |
|                                                 |
|                                                 |
|                                                 |
|                                                 |
|                                                 |
|                                                 |
---------------------------------------------------

MXD: memory selection                   0 = VRAM, 1 = expansion RAM

DX: origin X-coordinate (0 to 511)
DY: origin Y-coordinate (0 to 1023)

CLR (R#44:Colour register):  point colour
Figure 4.100 Register settings of PSET command
> PSET register setup

    MSB   7    6    5    4    3    2    1    0    LSB
        -----------------------------------------
R#36    | DX7| DX6| DX5| DX4| DX3| DX2| DX1| DX0|
        |----+----+----+----+----+----+----+----| DX ---+
R#37    | 0  | 0  | 0  | 0  | 0  | 0  | 0  | DX8|       |
        -----------------------------------------       |
                                                        | origin
        -----------------------------------------       |
R#38    | DY7| DY6| DY5| DY4| DY3| DY2| DY1| DY0|       |
        |----+----+----+----+----+----+----+----| DY ---+
R#39    | 0  | 0  | 0  | 0  | 0  | 0  | DY9| DY8|
        -----------------------------------------

        -----------------------------------------                     --+
R#44    | 0  | 0  | 0  | 0  | CR3| CR2| CR1| CR0| CLR (GRAPHIC 4,6)     |
        -----------------------------------------                       |
                                                                        |
        -----------------------------------------                       |
        | 0  | 0  | 0  | 0  | 0  | 0  | CR1| CR0| CLR (GRAPHIC 5)       | colour code data
        -----------------------------------------                       |
                                                                        |
        -----------------------------------------                       |
        | CR7| CR6| CR5| CR4| CR3| CR2| CR1| CR0| CLR (GRAPHIC 7)       |
        -----------------------------------------                     --+

        -----------------------------------------
R#45    | 0  | -- | MXD| -- | -- | -- | -- | -- | ARG (Argument register)
        -----------------------------------------
                     |
                     +-----------> memory selection

> PSET command execution

    MSB   7    6    5    4    3    2    1    0    LSB
        -----------------------------------------
R#46    | 0  | 1  | 0  | 1  | L03| L02| L01| L00| CMR
        -----------------------------------------
                            |                   |
                            +-------------------+
                              Logical operation
List 4.20 Example of PSET command execution
;****************************************************************
;  List 4.20   PSET sample
;                to use, set H, L, E, A as follows
;                pset (x:H, y:L), color:E, logi-OP:A
;****************************************************************
;
        PUBLIC  PSET

RDVDP:  EQU     0006H
WRVDP:  EQU     0007H

;----- program start -----

PSET:   DI
        PUSH    AF
        CALL    WAIT.VDP
        LD      BC,(WRVDP)

        INC     C
        LD      A,36
        OUT     (C),A
        LD      A,80H+17
        OUT     (C),A

        PUSH    BC
        INC     C
        INC     C
        XOR     A
        OUT     (C),H
        OUT     (C),A
        OUT     (C),L
        OUT     (C),A
        POP     BC

        LD      A,44
        OUT     (C),A
        LD      A,80H+17
        OUT     (C),A

        INC     C
        INC     C
        OUT     (C),E
        XOR     A
        OUT     (C),A

        LD      E,01010000B
        POP     AF
        OR      E
        OUT     (C),A

        EI
        RET

GET.STATUS:
        PUSH    BC
        LD      BC,(WRVDP)
        INC     C
        OUT     (C),A
        LD      A,8FH
        OUT     (C),A
        LD      BC,(RDVDP)
        INC     C
        IN      A,(C)
        POP     BC
        RET

WAIT.VDP:
        LD      A,2
        CALL    GET.STATUS
        AND     1
        JP      NZ,WAIT.VDP
        XOR     A
        CALL    GET.STATUS
        RET

        END

 

6.5.12 POINT (reading a colour code)

POINT reads the colour code in any coordinate of VRAM (see Figure 4.101).

After setting the parameters as shown in Figure 4.102, writing 40H in R#46 causes the command to be executed. While the CE bit of S#2 is “1”, the command is being executed. After the command terminates, the colour code of the specified coordinate is set in S#7. List 4.21 shows an example of using POINT.

Figure 4.101 Actions of POINT command
              VRAM or expansion RAM
---------------------------------------------------
|                                                 |
|                                                 |
|                                                 |
|                                                 |
|              (SX,SY)                            |
|                 x                               |
|                                                 |
|                                                 |
|                                                 |
|                                                 |
|                                                 |
|                                                 |
---------------------------------------------------

MXD: memory selection                   0 = VRAM, 1 = expansion RAM

SX:  origin X-coordinate (0 to 511)
SY:  origin Y-coordinate (0 to 1023)
Figure 4.102 Register settings of POINT command
> POINT register setup

    MSB   7    6    5    4    3    2    1    0    LSB
        -----------------------------------------
R#32    | SX7| SX6| SX5| SX4| SX3| SX2| SX1| SX0|
        |----+----+----+----+----+----+----+----| SX ---+
R#33    | 0  | 0  | 0  | 0  | 0  | 0  | 0  | SX8|       |
        -----------------------------------------       |
                                                        | origin
        -----------------------------------------       |
R#34    | SY7| SY6| SY5| SY4| SY3| SY2| SY1| SY0|       |
        |----+----+----+----+----+----+----+----| SY ---+
R#35    | 0  | 0  | 0  | 0  | 0  | 0  | SY9| SY8|
        -----------------------------------------

        -----------------------------------------
R#45    | -- | -- | -- | MXS| -- | -- | -- | -- | ARG (Argument register)
        -----------------------------------------
                          |
                          +-----------> memory selection

> POINT command execution

    MSB   7    6    5    4    3    2    1    0    LSB
        -----------------------------------------
R#46    | 0  | 1  | 0  | 0  | -- | -- | -- | -- | CMR
        -----------------------------------------

        -----------------------------------------
S#2     | -- | -- | -- | -- | -- | -- | -- | CE | CMR
        -----------------------------------------
                                             when the command ends : 0

        -----------------------------------------                    --+
S#7     | 0  | 0  | 0  | 0  | C3 | C2 | C1 | C0 | CL (GRAPHIC 4,6)     |
        -----------------------------------------                      |
                                                                       |
        -----------------------------------------                      |
        | 0  | 0  | 0  | 0  | 0  | 0  | C1 | C0 | CL (GRAPHIC 5)       | colour code data
        -----------------------------------------                      |
                                                                       |
        -----------------------------------------                      |
        | C7 | C6 | C5 | C4 | C3 | C2 | C1 | C0 | CL (GRAPHIC 7)       |
        -----------------------------------------                    --+
List 4.21 Example of POINT command execution
;****************************************************************
;  List 4.21   POINT sample
;                to use, set H, L as follows
;                POINT ( x:H, y:L )
;                returns:   A := COLOR CODE
;****************************************************************
;
        PUBLIC  POINT

RDVDP:  EQU     0006H
WRVDP:  EQU     0007H

;----- program start -----

POINT:  DI
        CALL    WAIT.VDP

        LD      A,(WRVDP)
        LD      C,A

        INC     C
        LD      A,32
        OUT     (C),A
        LD      A,80H+17
        OUT     (C),A

        INC     C
        INC     C
        XOR     A
        OUT     (C),H
        OUT     (C),A
        OUT     (C),L
        OUT     (C),A

        DEC     C
        DEC     C
        OUT     (C),A
        LD      A,80H+45
        OUT     (C),A
        LD      A,01000000B
        OUT     (C),A
        LD      A,80H+46
        OUT     (C),A
        CALL    WAIT.VDP
        LD      A,7
        CALL    GET.STATUS
        PUSH    AF
        XOR     A
        CALL    GET.STATUS
        POP     AF

        EI
        RET

GET.STATUS:
        PUSH    BC
        LD      BC,(WRVDP)
        INC     C
        OUT     (C),A
        LD      A,8FH
        OUT     (C),A
        LD      BC,(RDVDP)
        INC     C
        IN      A,(C)
        POP     BC
        RET

WAIT.VDP:
        LD      A,2
        CALL    GET.STATUS
        AND     1
        JP      NZ,WAIT.VDP
        XOR     A
        CALL    GET.STATUS
        RET

        END
List 4.22 PAINT routine using PSET and POINT
;****************************************************************
;  List 4.22  paint routine using PSET and POINT
;       ENTRY:  X:H, Y:L, BORDER COLOR:D, PAINT COLOR:E
;****************************************************************
;
        EXTRN   PSET
        EXTRN   POINT

Q.LENGTH        EQU     256*2*2
MAX.Y           EQU     211

;----- paint main routine -----

PAINT:  CALL    POINT
        CP      D
        RET     Z
        CALL    INIT.Q
        LD      (COL),DE
        CALL    PUT.Q
        LD      A,(COL)
        LD      E,A
        XOR     A                       ;logi-OP : PSET
        CALL    PSET
PAINT0: CALL    GET.Q
        RET     C
        INC     H
        CALL    NZ,PAINT.SUB
        DEC     H
        JP      Z,PAINT1
        DEC     H
        CALL    PAINT.SUB
        INC     H
PAINT1: DEC     L
        LD      A,-1
        CP      L
        CALL    NZ,PAINT.SUB
        INC     L
        INC     L
        LD      A,MAX.Y
        CP      L
        CALL    NC,PAINT.SUB
        JP      PAINT0

;----- check point and pset -----

PAINT.SUB:
        CALL    POINT
        LD      D,A
        LD      A,(BORD)
        CP      D
        RET     Z
        LD      A,(COL)
        CP      D
        RET     Z
        LD      E,A
        XOR     A
        CALL    PSET
        CALL    PUT.Q
        RET

;----- init Q.BUFFER pointer -----

INIT.Q:
        PUSH    HL
        LD      HL,Q.BUF
        LD      (Q.TOP),HL
        LD      (Q.BTM),HL
        POP     HL
        RET

;----- put point to Q.BUF (X:H , Y:L) -----

PUT.Q:
        EX      DE,HL
        LD      HL,(Q.TOP)
        LD      BC,Q.BUF+Q.LENGTH+1
        OR      A                       ;clear CARRY
        PUSH    HL
        SBC     HL,BC
        POP     HL
        JP      C,PUT.Q1
        LD      HL,Q.BUF
PUT.Q1:
        LD      (HL),D
        INC     HL
        LD      (HL),E
        INC     HL
        LD      (Q.TOP),HL
        EX      DE,HL
        RET

;----- take point data to D, E -----
;      returns:   NC   H:x, L:y
;                 C    buffer empty

GET.Q:  LD      HL,(Q.BTM)
        LD      BC,(Q.TOP)
        OR      A
        SBC     HL,BC
        JP      NZ,GET.Q0
        SCF
        RET

GET.Q0: LD      HL,(Q.BTM)
        LD      BC,Q.BUF+Q.LENGTH+1
        OR      A
        PUSH    HL
        SBC     HL,BC
        POP     HL
        JP      C,GET.Q1

        LD      HL,Q.BUF
GET.Q1: LD      D,(HL)
        INC     HL
        LD      E,(HL)
        INC     HL
        LD      (Q.BTM),HL
        OR      A
        EX      DE,HL
        RET

;----- work area -----

COL     DS      1
BORD    DS      1
Q.TOP   DS      2
Q.BTM   DS      2
Q.BUF   DS      Q.LENGTH

        END
List 4.23 Example of using the PAINT routine
1000 '***********************************************
1010 ' List 4.23   paint routine using POINT and PSET
1020 ' Position cursor at beginnig of paint area and press the space bar.
1030 '***********************************************
1040 '
1050 SCREEN 5
1060 FOR I=0 TO 50
1070 LINE -(RND(1)*255,RND(1)*211),15
1080 NEXT
1090 I=&HA000 :DEF USR=I
1100 READ A$
1110 IF  A$="END" THEN 1150
1120   POKE I,VAL("&H"+A$):I=I+1
1130   READ A$
1140 GOTO 1110
1150 X=128:Y=100:COL=15:PCOL=2
1160 CURS=0
1170 A=STICK(0)
1180 CURS=(CURS+1) AND 1
1190 LINE (X-5,I)-(X+5,I),15,,XOR
1200 LINE (X,Y-5)-(X,Y+5),15,,XOR
1210 IF CURS=1 THEN 1310
1220 IF A=1 THEN Y=Y-1
1230 IF A=2 THEN Y=Y-1:X=X+1
1240 IF A=3 THEN X=X+1
1250 IF A=4 THEN X=X+1:Y=Y+1
1260 IF A=5 THEN Y=Y+1
1270 IF A=6 THEN Y=Y+1:X=X-1
1280 IF A=7 THEN X=X-1
1290 IF A=8 THEN X=X-1:Y=Y-1
1300 IF STRIG(9) THEN GOSUB 1320
1310 GOTO 1170
1320 POKE &HA8CA,Y
1330 POKE &HA8CB,X
1340 POKE &HA8CD,COL
1350 POKE &HA8CC,PCOL
1360 A=USR(0)
1370 RETURN
1380 DATA ED,73,00,A8,31,CA,A8,2A,CA,A8,ED,5B,CC,A8,CD,67
1390 DATA A0,ED,7B,00,A8,C9,E5,21,D4,A8,22,D0,A8,22,D2,A8
1400 DATA E1,C9,EB,2A,D0,A8,01,D5,AC,B7,E5,ED,42,E1,DA,34
1410 DATA A0,21,D4,A8,72,23,73,23,22,D0,A8,EB,C9,2A,D2,A8
1420 DATA ED,4B,D0,A8,B7,ED,42,C2,4C,A0,37,C9,2A,D2,A8,01
1430 DATA D5,AC,B7,E5,ED,42,E1,DA,5D,A0,21,D4,A8,56,23,5E
1440 DATA 23,22,D2,A8,B7,EB,C9,CD,B8,A0,BA,C8,CD,16,A0,ED
1450 DATA 53,CE,A8,CD,22,A0,3A,CE,A8,5F,AF,CD,F4,A0,CD,3D
1460 DATA A0,D8,24,C4,A1,A0,25,CA,8F,A0,25,CD,A1,A0,24,2D
1470 DATA 3E,FF,BD,C4,A1,A0,2C,2C,3E,D3,BD,D4,A1,A0,C3,7E
1480 DATA A0,CD,B8,A0,57,3A,CF,A8,BA,C8,3A,CE,A8,BA,C8,5F
1490 DATA AF,CD,F4,A0,CD,22,A0,C9,F3,CD,3A,A1,ED,4B,06,00
1500 DATA 0C,3E,20,ED,79,3E,91,ED,79,0C,0C,AF,ED,61,ED,79
1510 DATA ED,69,ED,79,0D,0D,ED,79,3E,AD,ED,79,3E,40,ED,79
1520 DATA 3E,AE,ED,79,CD,3A,A1,3E,07,CD,2A,A1,F5,AF,CD,2A
1530 DATA A1,F1,FB,C9,F3,F5,CD,3A,A1,ED,4B,06,00,0C,3E,24
1540 DATA ED,79,3E,91,ED,79,C5,0C,0C,AF,ED,61,ED,79,ED,69
1550 DATA ED,79,C1,3E,2C,ED,79,3E,91,ED,79,0C,0C,ED,59,AF
1560 DATA ED,79,1E,50,F1,B3,ED,79,FB,C9,C5,ED,4B,06,00,0C
1570 DATA ED,79,3E,8F,ED,79,ED,78,C1,C9,3E,02,CD,2A,A1,E6
1580 DATA 01,C2,3A,A1,AF,CD,2A,A1,C9
1590 DATA END

 

6.6 Speeding Up Commands

MSX-VIDEO performs various screen management duties in addition to executing the specified commands. Sometimes the command execution speed seems to be a bit slow because of this. Thus, by discarding these operations, the speed of the command executions can be made faster. This can be done using the following method.

1. Sprite display inhibition

This method is useful since speedup can be realised while the screen remains displayed. Set “1” to bit 1 of R#8.

2. Screen display inhibition

This method cannot be used frequently except in the case of initialising the screen, since the screen fades out in this mode. Set “1” to bit 6 of R#1.

 

6.7 Register Status at Command Termination

Table 4.7 shows the register status at the command termination for each command.

When the number of dots to be executed in Y direction assumes N, the values of SY, DY, and NYB can be calculated as follows:

    SY*=SY+N, DY*=DY+N .................... when DIY bit is 0
    SY*=SY-N, DY*=DY-N .................... when DIY bit is 1
    NYB=NY-N

Note: when MAJ bit is 0 in LINE, N = N - 1.

Table 4.7 Register status at command termination
----------------------------------------------------------------------------
| command name | SX  | SY  | DX  | DY  | NX  | NY  | CLR |CMR H|CMR L| ARG |
|--------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----|
|     HMMC     | --- | --- | --- |  .  | --- |  #  | --- |  0  | --- | --- |
|--------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----|
|     YMMM     | --- |  .  | --- |  .  | --- |  #  | --- |  0  | --- | --- |
|--------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----|
|     HMMM     | --- |  .  | --- |  .  | --- |  #  | --- |  0  | --- | --- |
|--------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----|
|     HMMV     | --- | --- | --- |  .  | --- |  #  | --- |  0  | --- | --- |
----------------------------------------------------------------------------
----------------------------------------------------------------------------
|     LMMC     | --- | --- | --- |  .  | --- |  #  | --- |  0  | --- | --- |
|--------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----|
|     LMCM     | --- |  .  | --- | --- | --- |  #  |  .  |  0  | --- | --- |
|--------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----|
|     LMMM     | --- |  .  | --- |  .  | --- |  #  | --- |  0  | --- | --- |
|--------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----|
|     LMMV     | --- | --- | --- |  .  | --- |  #  | --- |  0  | --- | --- |
----------------------------------------------------------------------------
----------------------------------------------------------------------------
|     LINE     | --- | --- | --- |  .  | --- | --- | --- |  0  | --- | --- |
|--------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----|
|     SRCH     | --- | --- | --- | --- | --- | --- | --- |  0  | --- | --- |
|--------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----|
|     PSET     | --- | --- | --- | --- | --- | --- | --- |  0  | --- | --- |
|--------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----|
|     POINT    | --- | --- | --- | --- | --- | --- |  .  |  0  | --- | --- |
----------------------------------------------------------------------------

--- :   no change
 .  :   coordinate (SY*, DY*) and the colour code at the command termination
 #  :   the number of counts (NYB), when the screen edge is fetched

Changes from the original