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cc65/libsrc/geos-cbm/tgi/geos-tgi.s
2013-06-01 12:42:00 +02:00

682 lines
17 KiB
ArmAsm

;
; Graphics driver for the 320x200x2 and 640x200x2 modes on GEOS 64/128
; 2010-08-17, Maciej 'YTM/Elysium' Witkowiak <ytm@elysium.pl>
; 2010-08-18, Greg King
.include "zeropage.inc"
.include "tgi-kernel.inc"
.include "tgi-error.inc"
.include "const.inc"
.include "jumptab.inc"
.include "geossym.inc"
.include "geossym2.inc"
.macpack generic
; ------------------------------------------------------------------------
; Constants
VDC_ADDR_REG := $D600 ; VDC address
VDC_DATA_REG := $D601 ; VDC data
VDC_DSP_HI = 12 ; registers used
VDC_DSP_LO = 13
VDC_DATA_HI = 18
VDC_DATA_LO = 19
VDC_VSCROLL = 24
VDC_HSCROLL = 25
VDC_COLORS = 26
VDC_CSET = 28
VDC_COUNT = 30
VDC_DATA = 31
; ------------------------------------------------------------------------
; Header. Includes jump table and constants.
.segment "JUMPTABLE"
; First part of the header is a structure that has a magic signature,
; and defines the capabilities of the driver.
.byte $74, $67, $69 ; "tgi"
.byte TGI_API_VERSION ; TGI API version number
.addr $0000 ; Library reference
xres: .word 320 ; X resolution
yres: .word 200 ; Y resolution
.byte 2 ; Number of drawing colors
pages: .byte 1 ; Number of screens available
.byte 8 ; System font X size
.byte 8 ; System font Y size
aspect: .word $00D4 ; Aspect ratio (based on 4/3 display)
.byte 0 ; TGI driver flags
; Next comes the jump table. With the exception of IRQ, all entries must be
; valid, and may point to an RTS for test versions (function not implemented).
.addr INSTALL
.addr UNINSTALL
.addr INIT
.addr DONE
.addr GETERROR
.addr CONTROL
.addr CLEAR
.addr SETVIEWPAGE
.addr SETDRAWPAGE
.addr SETCOLOR
.addr SETPALETTE
.addr GETPALETTE
.addr GETDEFPALETTE
.addr SETPIXEL
.addr GETPIXEL
.addr LINE
.addr BAR
.addr TEXTSTYLE
.addr OUTTEXT
.addr 0 ; IRQ entry is unused
; ------------------------------------------------------------------------
; Data.
; Variables mapped to the zero-page segment variables. Some of these are
; used for passing parameters to the driver.
X1 = ptr1
Y1 = ptr2
X2 = ptr3
Y2 = ptr4
; Absolute variables used in the code
.bss
SCRBASE:
.res 1 ; High byte of screen base (64k VDC only)
ERROR:
.res 1 ; Error code
PALETTE:
.res 2 ; The current palette
BITMASK:
.res 1 ; $00 = clear, $01 = set pixels
OLDCOLOR:
.res 1 ; colors before entering gfx mode
; Text output stuff
TEXTMAGX:
.res 1
TEXTMAGY:
.res 1
TEXTDIR:
.res 1
; Constants and tables
.rodata
DEFPALETTE:
.byte $00, $0f ; White on black
PALETTESIZE = * - DEFPALETTE
; color translation table (indexed by VIC color)
COLTRANS:
.byte $00, $0f, $08, $06, $0a, $04, $02, $0c
.byte $0d, $0b, $09, $01, $0e, $05, $03, $07
; colors BROWN and GRAY3 are wrong
.code
; ------------------------------------------------------------------------
; INSTALL routine. Is called after the driver is loaded into memory. May
; initialize anything that has to be done just once. Is probably empty
; most of the time.
;
; Must set an error code: NO
;
INSTALL:
lda version ; if GEOS 1.0...
and #$f0
cmp #$10
beq @L40
lda c128Flag ; at least GEOS 2.0, but we're on C128?
bpl @L40
lda graphMode ; GEOS 2.0, C128, but is 80 column screen enabled?
bmi @L80
@L40: rts ; leave default values for 40 column screen
; check for VDC version and update register $19 value
@L80:
; double the x resolution and halve the aspect ratio
asl xres
rol xres+1
lsr aspect+1
ror aspect
; update number of available screens
ldx #VDC_CSET ; determine size of RAM...
jsr VDCReadReg
sta tmp1
ora #%00010000
jsr VDCWriteReg ; turn on 64k
jsr settestadr1 ; save original value of test byte
jsr VDCReadByte
sta tmp2
lda #$55 ; write $55 here
ldy #ptr1
jsr test64k ; read it here and there
lda #$aa ; write $aa here
ldy #ptr2
jsr test64k ; read it here and there
jsr settestadr1
lda tmp2
jsr VDCWriteByte ; restore original value of test byte
lda ptr1 ; do bytes match?
cmp ptr1+1
bne @have64k
lda ptr2
cmp ptr2+1
bne @have64k
ldx #VDC_CSET
lda tmp1
jsr VDCWriteReg ; restore 16/64k flag
jmp @endok ; and leave default values for 16k
@have64k:
lda #4
sta pages
@endok:
lda #0
sta SCRBASE ; draw page 0 as default
rts
test64k:
sta tmp1
sty ptr3
lda #0
sta ptr3+1
jsr settestadr1
lda tmp1
jsr VDCWriteByte ; write $55
jsr settestadr1
jsr VDCReadByte ; read here
pha
jsr settestadr2
jsr VDCReadByte ; and there
ldy #1
sta (ptr3),y
pla
dey
sta (ptr3),y
rts
settestadr1:
ldy #$02 ; test page 2 (here)
.byte $2c
settestadr2:
ldy #$42 ; or page 64+2 (there)
lda #0
jmp VDCSetSourceAddr
; ------------------------------------------------------------------------
; UNINSTALL routine. Is called before the driver is removed from memory. May
; clean up anything done by INSTALL but is probably empty most of the time.
;
; Must set an error code: NO
;
UNINSTALL:
rts
; ------------------------------------------------------------------------
; INIT: Changes an already installed device from text mode to graphics
; mode.
; Note that INIT/DONE may be called multiple times while the driver
; is loaded, while INSTALL is only called once, so any code that is needed
; to initializes variables and so on must go here. Setting palette and
; clearing the screen is not needed because this is called by the graphics
; kernel later.
; The graphics kernel will never call INIT when a graphics mode is already
; active, so there is no need to protect against that.
;
; Must set an error code: YES
;
INIT:
ldx #$01
stx BITMASK ; solid black as pattern
lda #1
jsr SetPattern
lda #ST_WR_FORE ; write only on foreground
sta dispBufferOn
lda graphMode
bmi @L80
; Remember current color value (40 columns)
lda screencolors
sta OLDCOLOR
jmp @L99
; Remember current color value (80 columns)
@L80: lda scr80colors
sta OLDCOLOR
@L99: lda #0
jsr SETVIEWPAGE ; switch into viewpage 0
; Done, reset the error code
lda #TGI_ERR_OK
sta ERROR
rts
; ------------------------------------------------------------------------
; DONE: Will be called to switch the graphics device back into text mode.
; The graphics kernel will never call DONE when no graphics mode is active,
; so there is no need to protect against that.
;
; Must set an error code: NO
;
DONE:
lda #0
jsr SETVIEWPAGE ; switch into viewpage 0
lda graphMode
bmi @L80
lda OLDCOLOR
sta screencolors ; restore color for 40 columns
ldx #0
@L1: sta COLOR_MATRIX,x
sta COLOR_MATRIX+$0100,x
sta COLOR_MATRIX+$0200,x
sta COLOR_MATRIX+1000-256,x
inx
bne @L1
rts
@L80: lda OLDCOLOR ; restore color for 80 columns
ldx #VDC_COLORS
jmp VDCWriteReg
; ------------------------------------------------------------------------
; GETERROR: Return the error code in A and clear it.
GETERROR:
ldx #TGI_ERR_OK
lda ERROR
stx ERROR
rts
; ------------------------------------------------------------------------
; CONTROL: Platform/driver specific entry point.
;
; Must set an error code: YES
;
CONTROL:
lda #TGI_ERR_INV_FUNC
sta ERROR
rts
; ------------------------------------------------------------------------
; CLEAR: Clears the screen.
;
; Must set an error code: NO
;
CLEAR:
lda curPattern
pha
lda #0
jsr SetPattern
ldx #0
stx r3L
stx r3H
stx r2L
lda #199
sta r2H
lda graphMode
bpl @L40
lda #>639 ; 80 columns
ldx #<639
bne @L99
@L40: lda #>319 ; 40 columns
ldx #<319
@L99: sta r4H
stx r4L
jsr Rectangle
pla
sta curPattern
rts
; ------------------------------------------------------------------------
; SETVIEWPAGE: Set the visible page. Called with the new page in A (0..n).
; The page number is already checked to be valid by the graphics kernel.
;
; Must set an error code: NO (will only be called if page ok)
;
SETVIEWPAGE:
ldx graphMode
bmi @L80
rts
@L80: clc
ror
ror
ror
ldx #VDC_DSP_HI
jmp VDCWriteReg
; ------------------------------------------------------------------------
; SETDRAWPAGE: Set the drawable page. Called with the new page in A (0..n).
; The page number is already checked to be valid by the graphics kernel.
;
; Must set an error code: NO (will only be called if page ok)
;
SETDRAWPAGE:
ldx graphMode
bmi @L80
rts
@L80: clc
ror
ror
ror
sta SCRBASE
rts
; ------------------------------------------------------------------------
; SETCOLOR: Set the drawing color (in A). The new color is already checked
; to be in a valid range (0..maxcolor-1).
;
; Must set an error code: NO (will only be called if color ok)
;
SETCOLOR:
tax
beq @L1
lda #1
@L1: sta BITMASK
jmp SetPattern ; need to have either 0 or 1
; ------------------------------------------------------------------------
; SETPALETTE: Set the palette (not available with all drivers/hardware).
; A pointer to the palette is passed in ptr1. Must set an error if palettes
; are not supported
;
; Must set an error code: YES
;
SETPALETTE:
jsr GETERROR ; clear error (if any)
ldy #PALETTESIZE - 1
@L1: lda (ptr1),y ; Copy the palette
and #$0F ; Make a valid color
sta PALETTE,y
dey
bpl @L1
; Put colors from palette into screen
lda graphMode
bmi @L80
lda PALETTE+1 ; foreground
asl a
asl a
asl a
asl a
ora PALETTE ; background
ldx #0
@L2: sta COLOR_MATRIX,x
sta COLOR_MATRIX+$0100,x
sta COLOR_MATRIX+$0200,x
sta COLOR_MATRIX+1000-256,x
inx
bne @L2
rts
@L80: ldy PALETTE+1 ; Foreground color
lda COLTRANS,y
asl a
asl a
asl a
asl a
ldy PALETTE ; Background color
ora COLTRANS,y
ldx #VDC_COLORS
jmp VDCWriteReg
; ------------------------------------------------------------------------
; GETPALETTE: Return the current palette in A/X. Even drivers that cannot
; set the palette should return the default palette here, so there's no
; way for this function to fail.
;
; Must set an error code: NO
;
GETPALETTE:
lda #<PALETTE
ldx #>PALETTE
rts
; ------------------------------------------------------------------------
; GETDEFPALETTE: Return the default palette for the driver in A/X. All
; drivers should return something reasonable here, even drivers that don't
; support palettes, otherwise the caller has no way to determine the colors
; of the (not changeable) palette.
;
; Must set an error code: NO (all drivers must have a default palette)
;
GETDEFPALETTE:
lda #<DEFPALETTE
ldx #>DEFPALETTE
rts
; ------------------------------------------------------------------------
; SETPIXEL: Draw one pixel at X1/Y1 = ptr1/ptr2 with the current drawing
; color. The coordinates passed to this function are never outside the
; visible screen area, so there is no need for clipping inside this function.
;
; Must set an error code: NO
;
SETPIXEL:
lda X1
ldx X1+1
ldy Y1
sta r3L
stx r3H
sty r11L
sec
lda BITMASK ; set or clear C flag
bne @L1
clc
@L1: lda #0
jmp DrawPoint
; ------------------------------------------------------------------------
; GETPIXEL: Read the color value of a pixel and return it in A/X. The
; coordinates passed to this function are never outside the visible screen
; area, so there is no need for clipping inside this function.
GETPIXEL:
lda X1
ldx X1+1
ldy Y1
sta r3L
stx r3H
sty r11L
jsr TestPoint
ldx #0
bcc @L1
inx
@L1: txa
ldx #0
rts
; ------------------------------------------------------------------------
; LINE: Draw a line from X1/Y1 to X2/Y2, where X1/Y1 = ptr1/ptr2 and
; X2/Y2 = ptr3/ptr4 using the current drawing color.
;
; Must set an error code: NO
;
LINE:
lda X1
ldx X1+1
ldy Y1
sta r3L
stx r3H
sty r11L
lda X2
ldx X2+1
ldy Y2
sta r4L
stx r4H
sty r11H
sec
lda BITMASK ; set or clear C flag
bne @L1
clc
@L1: lda #0
jmp DrawLine
; ------------------------------------------------------------------------
; BAR: Draw a filled rectangle with the corners X1/Y1, X2/Y2, where
; X1/Y1 = ptr1/ptr2 and X2/Y2 = ptr3/ptr4 using the current drawing color.
; Contrary to most other functions, the graphics kernel will sort and clip
; the coordinates before calling the driver, so on entry the following
; conditions are valid:
; X1 <= X2
; Y1 <= Y2
; (X1 >= 0) && (X1 < XRES)
; (X2 >= 0) && (X2 < XRES)
; (Y1 >= 0) && (Y1 < YRES)
; (Y2 >= 0) && (Y2 < YRES)
;
; Must set an error code: NO
;
BAR:
lda X1
ldx X1+1
ldy Y1
sta r3L
stx r3H
sty r2L
lda X2
ldx X2+1
ldy Y2
sta r4L
stx r4H
sty r2H
jmp Rectangle
; ------------------------------------------------------------------------
; TEXTSTYLE: Set the style used when calling OUTTEXT. Text scaling in X and Y
; direction is passend in X/Y, the text direction is passed in A.
;
; Must set an error code: NO
;
TEXTSTYLE:
stx TEXTMAGX
sty TEXTMAGY
sta TEXTDIR
rts
; ------------------------------------------------------------------------
; OUTTEXT: Output text at X/Y = ptr1/ptr2 using the current color and the
; current text style. The text to output is given as a zero terminated
; string with address in ptr3.
;
; Must set an error code: NO
;
OUTTEXT:
lda TEXTDIR
; cmp #TGI_TEXT_HORIZONTAL ; this is equal 0
bne @vertical
lda X1 ; horizontal text output
ldx X1+1
ldy Y1
sta r11L
stx r11H
sty r1H
lda ptr3
ldx ptr3+1
sta r0L
stx r0H
jmp PutString
@vertical:
lda X1 ; vertical text output
ldx X1+1
ldy Y1
sta r11L
stx r11H
sty r1H
ldy #0
lda (ptr3),y
beq @end
jsr PutChar
inc ptr3
bne @L1
inc ptr3+1
@L1: lda Y1
clc
adc #8
sta Y1
bne @vertical
@end: rts
;-------------
; VDC helpers
VDCSetSourceAddr:
pha
tya
ldx #VDC_DATA_HI
jsr VDCWriteReg
pla
ldx #VDC_DATA_LO
bne VDCWriteReg
VDCReadByte:
ldx #VDC_DATA
VDCReadReg:
stx VDC_ADDR_REG
@L0: bit VDC_ADDR_REG
bpl @L0
lda VDC_DATA_REG
rts
VDCWriteByte:
ldx #VDC_DATA
VDCWriteReg:
stx VDC_ADDR_REG
@L0: bit VDC_ADDR_REG
bpl @L0
sta VDC_DATA_REG
rts