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More VGA tests

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Jeff Parsons 2015-06-29 09:42:44 -07:00
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235
tests/pc/vga/L28-1.ASM Normal file
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; Program to illustrate the use of the Read Map register in read mode 0.
; Animates by copying a 16-color image from VGA memory to system memory,
; one plane at a time, then copying the image back to a new location
; in VGA memory.
;
; By Michael Abrash
;
stack segment word stack 'STACK'
db 512 dup (?)
stack ends
;
data segment word 'DATA'
IMAGE_WIDTH EQU 4 ;in bytes
IMAGE_HEIGHT EQU 32 ;in pixels
LEFT_BOUND EQU 10 ;in bytes
RIGHT_BOUND EQU 66 ;in bytes
VGA_SEGMENT EQU 0a000h
SCREEN_WIDTH EQU 80 ;in bytes
SC_INDEX EQU 3c4h ;Sequence Controller Index register
GC_INDEX EQU 3ceh ;Graphics Controller Index register
MAP_MASK EQU 2 ;Map Mask register index in SC
READ_MAP EQU 4 ;Read Map register index in GC
;
; Base pattern for 16-color image.
;
PatternPlane0 label byte
db 32 dup (0ffh,0ffh,0,0)
PatternPlane1 label byte
db 32 dup (0ffh,0,0ffh,0)
PatternPlane2 label byte
db 32 dup (0f0h,0f0h,0f0h,0f0h)
PatternPlane3 label byte
db 32 dup (0cch,0cch,0cch,0cch)
;
; Temporary storage for 16-color image during animation.
;
ImagePlane0 db 32*4 dup (?)
ImagePlane1 db 32*4 dup (?)
ImagePlane2 db 32*4 dup (?)
ImagePlane3 db 32*4 dup (?)
;
; Current image location & direction.
;
ImageX dw 40 ;in bytes
ImageY dw 100 ;in pixels
ImageXDirection dw 1 ;in bytes
data ends
;
code segment word 'CODE'
assume cs:code,ds:data
Start proc near
cld
mov ax,data
mov ds,ax
;
; Select graphics mode 10h.
;
mov ax,10h
int 10h
;
; Draw the initial image.
;
mov si,offset PatternPlane0
call DrawImage
;
; Loop to animate by copying the image from VGA memory to system memory,
; erasing the image, and copying the image from system memory to a new
; location in VGA memory. Ends when a key is hit.
;
AnimateLoop:
;
; Copy the image from VGA memory to system memory.
;
mov di,offset ImagePlane0
call GetImage
;
; Clear the image from VGA memory.
;
call EraseImage
;
; Advance the image X coordinate, reversing direction if either edge
; of the screen has been reached.
;
mov ax,[ImageX]
cmp ax,LEFT_BOUND
jz ReverseDirection
cmp ax,RIGHT_BOUND
jnz SetNewX
ReverseDirection:
neg [ImageXDirection]
SetNewX:
add ax,[ImageXDirection]
mov [ImageX],ax
;
; Draw the image by copying it from system memory to VGA memory.
;
mov si,offset ImagePlane0
call DrawImage
;
; Slow things down a bit for visibility (adjust as needed).
;
mov cx,0
DelayLoop:
loop DelayLoop
;
; See if a key has been hit, ending the program.
;
mov ah,1
int 16h
jz AnimateLoop
;
; Clear the key, return to text mode, and return to DOS.
;
sub ah,ah
int 16h
mov ax,3
int 10h
mov ah,4ch
int 21h
Start endp
;
; Draws the image at offset DS:SI to the current image location in
; VGA memory.
;
DrawImage proc near
mov ax,VGA_SEGMENT
mov es,ax
call GetImageOffset ;ES:DI is the destination address for the
; image in VGA memory
mov dx,SC_INDEX
mov al,1 ;do plane 0 first
DrawImagePlaneLoop:
push di ;image is drawn at the same offset in
; each plane
push ax ;preserve plane select
mov al,MAP_MASK ;Map Mask index
out dx,al ;point SC Index to the Map Mask register
pop ax ;get back plane select
inc dx ;point to SC index register
out dx,al ;set up the Map Mask to allow writes to
; the plane of interest
dec dx ;point back to SC Data register
mov bx,IMAGE_HEIGHT ;# of scan lines in image
DrawImageLoop:
mov cx,IMAGE_WIDTH ;# of bytes across image
rep movsb
add di,SCREEN_WIDTH-IMAGE_WIDTH
;point to next scan line of image
dec bx ;any more scan lines?
jnz DrawImageLoop
pop di ;get back image start offset in VGA memory
shl al,1 ;Map Mask setting for next plane
cmp al,10h ;have we done all four planes?
jnz DrawImagePlaneLoop
ret
DrawImage endp
;
; Copies the image from its current location in VGA memory into the
; buffer at DS:DI.
;
GetImage proc near
mov si,di ;move destination offset into SI
call GetImageOffset ;DI is offset of image in VGA memory
xchg si,di ;SI is offset of image, DI is destination offset
push ds
pop es ;ES:DI is destination
mov ax,VGA_SEGMENT
mov ds,ax ;DS:SI is source
;
mov dx,GC_INDEX
sub al,al ;do plane 0 first
GetImagePlaneLoop:
push si ;image comes from same offset in each plane
push ax ;preserve plane select
mov al,READ_MAP ;Read Map index
out dx,al ;point GC Index to Read Map register
pop ax ;get back plane select
inc dx ;point to GC Index register
out dx,al ;set up the Read Map to select reads from
; the plane of interest
dec dx ;point back to GC data register
mov bx,IMAGE_HEIGHT ;# of scan lines in image
GetImageLoop:
mov cx,IMAGE_WIDTH ;# of bytes across image
rep movsb
add si,SCREEN_WIDTH-IMAGE_WIDTH
;point to next scan line of image
dec bx ;any more scan lines?
jnz GetImageLoop
pop si ;get back image start offset
inc al ;Read Map setting for next plane
cmp al,4 ;have we done all four planes?
jnz GetImagePlaneLoop
push es
pop ds ;restore original DS
ret
GetImage endp
;
; Erases the image at its current location.
;
EraseImage proc near
mov dx,SC_INDEX
mov al,MAP_MASK
out dx,al ;point SC Index to the Map Mask register
inc dx ;point to SC Data register
mov al,0fh
out dx,al ;set up the Map Mask to allow writes to go to
; all 4 planes
mov ax,VGA_SEGMENT
mov es,ax
call GetImageOffset ;ES:DI points to the start address
; of the image
sub al,al ;erase with zeros
mov bx,IMAGE_HEIGHT ;# of scan lines in image
EraseImageLoop:
mov cx,IMAGE_WIDTH ;# of bytes across image
rep stosb
add di,SCREEN_WIDTH-IMAGE_WIDTH
;point to next scan line of image
dec bx ;any more scan lines?
jnz EraseImageLoop
ret
EraseImage endp
;
; Returns the current offset of the image in the VGA segment in DI.
;
GetImageOffset proc near
mov ax,SCREEN_WIDTH
mul [ImageY]
add ax,[ImageX]
mov di,ax
ret
GetImageOffset endp
code ends
end Start

161
tests/pc/vga/L28-2.ASM Normal file
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; Program to illustrate use of read mode 1 (color compare mode)
; to detect collisions in display memory. Draws a yellow line on a
; blue background, then draws a perpendicular green line until the
; yellow line is reached.
;
; By Michael Abrash
;
stack segment word stack 'STACK'
db 512 dup (?)
stack ends
;
VGA_SEGMENT EQU 0a000h
SCREEN_WIDTH EQU 80 ;in bytes
GC_INDEX EQU 3ceh ;Graphics Controller Index register
SET_RESET EQU 0 ;Set/Reset register index in GC
ENABLE_SET_RESET EQU 1 ;Enable Set/Reset register index in GC
COLOR_COMPARE EQU 2 ;Color Compare register index in GC
GRAPHICS_MODE EQU 5 ;Graphics Mode register index in GC
BIT_MASK EQU 8 ;Bit Mask register index in GC
;
code segment word 'CODE'
assume cs:code
Start proc near
cld
;
; Select graphics mode 10h.
;
mov ax,10h
int 10h
;
; Fill the screen with blue.
;
mov al,1 ;blue is color 1
call SelectSetResetColor ;set to draw in blue
mov ax,VGA_SEGMENT
mov es,ax
sub di,di
mov cx,7000h
rep stosb ;the value written actually doesn't
; matter, since set/reset is providing
; the data written to display memory
;
; Draw a vertical yellow line.
;
mov al,14 ;yellow is color 14
call SelectSetResetColor ;set to draw in yellow
mov dx,GC_INDEX
mov al,BIT_MASK
out dx,al ;point GC Index to Bit Mask
inc dx ;point to GC Data
mov al,10h
out dx,al ;set Bit Mask to 10h
mov di,40 ;start in the middle of the top line
mov cx,350 ;do full height of screen
VLineLoop:
mov al,es:[di] ;load the latches
stosb ;write next pixel of yellow line (set/reset
; provides the data written to display
; memory, and AL is actually ignored)
add di,SCREEN_WIDTH-1 ;point to the next scan line
loop VLineLoop
;
; Select write mode 0 and read mode 1.
;
mov dx,GC_INDEX
mov al,GRAPHICS_MODE
out dx,al ;point GC Index to Graphics Mode register
inc dx ;point to GC Data
mov al,00001000b ;bit 3=1 is read mode 1, bits 1 & 0=00
; is write mode 0
out dx,al ;set Graphics Mode to read mode 1,
; write mode 0
;
; Draw a horizontal green line, one pixel at a time, from left
; to right until color compare reports a yellow pixel is encountered.
;
; Draw in green.
;
mov al,2 ;green is color 2
call SelectSetResetColor ;set to draw in green
;
; Set color compare to look for yellow.
;
mov dx,GC_INDEX
mov al,COLOR_COMPARE
out dx,al ;point GC Index to Color Compare register
inc dx ;point to GC Data
mov al,14 ;we're looking for yellow, color 14
out dx,al ;set color compare to look for yellow
dec dx ;point to GC Index
;
; Set up for quick access to Bit Mask register.
;
mov al,BIT_MASK
out dx,al ;point GC Index to Bit Mask register
inc dx ;point to GC Data
;
; Set initial pixel mask and display memory offset.
;
mov al,80h ;initial pixel mask
mov di,100*SCREEN_WIDTH
;start at left edge of scan line 100
HLineLoop:
mov ah,es:[di] ;do a read mode 1 (color compare) read.
; This also loads the latches.
and ah,al ;is the pixel of current interest yellow?
jnz WaitKeyAndDone ;yes-we've reached the yellow line, so we're
; done
out dx,al ;set the Bit Mask register so that we
; modify only the pixel of interest
mov es:[di],al ;draw the pixel. The value written is
; irrelevant, since set/reset is providing
; the data written to display memory
ror al,1 ;shift pixel mask to the next pixel
adc di,0 ;advance the display memory offset if
; the pixel mask wrapped
;
; Slow things down a bit for visibility (adjust as needed).
;
mov cx,0
DelayLoop:
loop DelayLoop
jmp HLineLoop
;
; Wait for a key to be pressed to end, then return to text mode and
; return to DOS.
;
WaitKeyAndDone:
WaitKeyLoop:
mov ah,1
int 16h
jz WaitKeyLoop
sub ah,ah
int 16h ;clear the key
mov ax,3
int 10h ;return to text mode
mov ah,4ch
int 21h ;done
Start endp
;
; Enables set/reset for all planes, and sets the set/reset color
; to AL.
;
SelectSetResetColor proc near
mov dx,GC_INDEX
push ax ;preserve color
mov al,SET_RESET
out dx,al ;point GC Index to Set/Reset register
inc dx ;point to GC Data
pop ax ;get back color
out dx,al ;set Set/Reset register to selected color
dec dx ;point to GC Index
mov al,ENABLE_SET_RESET
out dx,al ;point GC Index to Enable Set/Reset register
inc dx ;point to GC Data
mov al,0fh
out dx,al ;enable set/reset for all planes
ret
SelectSetResetColor endp
code ends
end Start

103
tests/pc/vga/L28-3.ASM Normal file
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; Program that draws a diagonal line to illustrate the use of a
; Color Don't Care register setting of 0FFH to support fast
; read-modify-write operations to VGA memory in write mode 3 by
; drawing a diagonal line.
;
; Note: Works on VGAs only.
;
; By Michael Abrash
;
stack segment word stack 'STACK'
db 512 dup (?)
stack ends
;
VGA_SEGMENT EQU 0a000h
SCREEN_WIDTH EQU 80 ;in bytes
GC_INDEX EQU 3ceh ;Graphics Controller Index register
SET_RESET EQU 0 ;Set/Reset register index in GC
ENABLE_SET_RESET EQU 1 ;Enable Set/Reset register index in GC
GRAPHICS_MODE EQU 5 ;Graphics Mode register index in GC
COLOR_DONT_CARE EQU 7 ;Color Don't Care register index in GC
;
code segment word 'CODE'
assume cs:code
Start proc near
;
; Select graphics mode 12h.
;
mov ax,12h
int 10h
;
; Select write mode 3 and read mode 1.
;
mov dx,GC_INDEX
mov al,GRAPHICS_MODE
out dx,al
inc dx
in al,dx ;VGA registers are readable, bless them!
or al,00001011b ;bit 3=1 selects read mode 1, and
; bits 1 & 0=11 selects write mode 3
jmp $+2 ;delay between IN and OUT to same port
out dx,al
dec dx
;
; Set up set/reset to always draw in white.
;
mov al,SET_RESET
out dx,al
inc dx
mov al,0fh
out dx,al
dec dx
mov al,ENABLE_SET_RESET
out dx,al
inc dx
mov al,0fh
out dx,al
dec dx
;
; Set Color Don't Care to 0, so reads of VGA memory always return 0FFH.
;
mov al,COLOR_DONT_CARE
out dx,al
inc dx
sub al,al
out dx,al
;
; Set up the initial memory pointer and pixel mask.
;
mov ax,VGA_SEGMENT
mov ds,ax
sub bx,bx
mov al,80h
;
; Draw 400 points on a diagonal line sloping down and to the right.
;
mov cx,400
DrawDiagonalLoop:
and [bx],al ;reads display memory, loading the latches,
; then writes AL to the VGA. AL becomes the
; bit mask, and set/reset provides the
; actual data written
add bx,SCREEN_WIDTH
; point to the next scan line
ror al,1 ;move the pixel mask one pixel to the right
adc bx,0 ;advance to the next byte if the pixel mask wrapped
loop DrawDiagonalLoop
;
; Wait for a key to be pressed to end, then return to text mode and
; return to DOS.
;
WaitKeyLoop:
mov ah,1
int 16h
jz WaitKeyLoop
sub ah,ah
int 16h ;clear the key
mov ax,3
int 10h ;return to text mode
mov ah,4ch
int 21h ;done
Start endp
code ends
end Start

4
tests/pc/vga/README.md
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@ -41,6 +41,10 @@ List of VGA Samples from [Michael Abrash's Graphics Programming Black Book](http
* [L27-1.ASM: Illustrates one use of write mode 2 of the VGA and EGA by animating the image of an "A"](L27-1.ASM) * [L27-1.ASM: Illustrates one use of write mode 2 of the VGA and EGA by animating the image of an "A"](L27-1.ASM)
* [L27-2.ASM: Illustrates one use of write mode 2 of the VGA and EGA by drawing lines in color patterns](L27-2.ASM) * [L27-2.ASM: Illustrates one use of write mode 2 of the VGA and EGA by drawing lines in color patterns](L27-2.ASM)
* [L27-3.ASM: Illustrates flipping from bit-mapped graphics mode to text mode and back](L27-3.ASM) * [L27-3.ASM: Illustrates flipping from bit-mapped graphics mode to text mode and back](L27-3.ASM)
* [Chapter 28](https://github.com/jeffpar/abrash-black-book/blob/master/src/chapter-28.md)
* [L28-1.ASM: Illustrates the use of the Read Map register in read mode 0](L28-1.ASM)
* [L28-2.ASM: Illustrates use of read mode 1 (color compare mode) to detect collisions in display memory](L28-2.ASM)
* [L28-3.ASM: Illustrates the use of Color Don't Care to support fast read-modify-write operations](L28-3.ASM)
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