2 ; Graphics driver for the 640x480x2 mode on the C128 VDC 64k
3 ; (values for this mode based on Fred Bowen's document)
4 ; Maciej 'YTM/Elysium' Witkowiak <ytm@elysium.pl>
8 ; For any smart monkey that will try to optimize this: PLEASE do tests on
9 ; real VDC, not only VICE.
11 ; Only DONE routine contains C128-mode specific stuff, everything else will
12 ; work in C64-mode of C128 (C64 needs full VDC init then).
14 ; With special initialization and CALC we can get 320x200 double-pixel mode.
16 ; Color translation values for BROWN and GRAY3 are obviously wrong, they
17 ; could be replaced by equiv. of ORANGE and GRAY2 but this would give only
18 ; 14 of 16 colors available.
20 ; Register 25 ($19) is said to require different value for VDC v1, but I
21 ; couldn't find what it should be.
23 .include "zeropage.inc"
25 .include "tgi-kernel.inc"
26 .include "tgi-mode.inc"
27 .include "tgi-error.inc"
32 ; ------------------------------------------------------------------------
35 VDC_ADDR_REG = $D600 ; VDC address
36 VDC_DATA_REG = $D601 ; VDC data
38 VDC_DSP_HI = 12 ; registers used
49 ; ------------------------------------------------------------------------
50 ; Header. Includes jump table and constants.
54 ; First part of the header is a structure that has a magic and defines the
55 ; capabilities of the driver
57 .byte $74, $67, $69 ; "tgi"
58 .byte TGI_API_VERSION ; TGI version number
59 xres: .word 640 ; X resolution
60 yres: .word 480 ; Y resolution
61 .byte 2 ; Number of drawing colors
62 pages: .byte 0 ; Number of screens available
63 .byte 8 ; System font X size
64 .byte 8 ; System font Y size
65 .res 4, $00 ; Reserved for future extensions
67 ; Next comes the jump table. Currently all entries must be valid and may point
68 ; to an RTS for test versions (function not implemented).
92 ; ------------------------------------------------------------------------
95 ; Variables mapped to the zero page segment variables. Some of these are
96 ; used for passing parameters to the driver.
104 ADDR = tmp1 ; (2) CALC
105 TEMP = tmp3 ; CALC icmp
108 TEMP4 = sreg+1 ; LINE
110 ; Line routine stuff (must be on zpage)
113 ERR = regsave ; (2) LINE
114 NX = regsave+2 ; (2) LINE
116 XX = ptr3 ; (2) CIRCLE
117 YY = ptr4 ; (2) CIRCLE
118 MaxO = sreg ; (overwritten by TEMP3+TEMP4, but restored from OG/OU anyway)
119 XS = regsave ; (2) CIRCLE
120 YS = regsave+2 ; (2) CIRCLE
122 ; Absolute variables used in the code
126 ERROR: .res 1 ; Error code
127 PALETTE: .res 2 ; The current palette
129 BITMASK: .res 1 ; $00 = clear, $FF = set pixels
131 OLDCOLOR: .res 1 ; colors before entering gfx mode
133 ; Line routine stuff (combined with CIRCLE to save space)
149 ; Constants and tables
153 DEFPALETTE: .byte $00, $0f ; White on black
154 PALETTESIZE = * - DEFPALETTE
156 BITTAB: .byte $80,$40,$20,$10,$08,$04,$02,$01
158 BITMASKL: .byte %11111111, %01111111, %00111111, %00011111
159 .byte %00001111, %00000111, %00000011, %00000001
161 BITMASKR: .byte %10000000, %11000000, %11100000, %11110000
162 .byte %11111000, %11111100, %11111110, %11111111
164 ; color translation table (indexed by VIC color)
165 COLTRANS: .byte $00, $0f, $08, $06, $0a, $04, $02, $0c
166 .byte $0d, $0b, $09, $01, $0e, $05, $03, $07
167 ; colors BROWN and GRAY3 are wrong
169 ; VDC initialization table (reg),(val),...,$ff
171 .byte VDC_DSP_HI, 0 ; viewpage 0 as default
173 .byte VDC_HSCROLL, $87
184 SCN80CLR: .byte 27,88,147,27,88,0
188 ; ------------------------------------------------------------------------
189 ; INSTALL routine. Is called after the driver is loaded into memory. May
190 ; initialize anything that has to be done just once. Is probably empty
193 ; Must set an error code: NO
197 ; check for VDC version and update register $19 value
199 ; check for VDC ram size and update number of available screens
201 ldx #VDC_CSET ; determine size of RAM...
205 jsr VDCWriteReg ; turn on 64k
207 jsr settestadr1 ; save original value of test byte
211 lda #$55 ; write $55 here
213 jsr test64k ; read it here and there
214 lda #$aa ; write $aa here
216 jsr test64k ; read it here and there
220 jsr VDCWriteByte ; restore original value of test byte
222 lda ptr1 ; do bytes match?
231 jsr VDCWriteReg ; restore 16/64k flag
232 jmp @endok ; and leave default values for 16k
247 jsr VDCWriteByte ; write $55
249 jsr VDCReadByte ; read here
252 jsr VDCReadByte ; and there
261 ldy #$02 ; test page 2 (here)
264 ldy #$42 ; or page 64+2 (there)
268 ; ------------------------------------------------------------------------
269 ; UNINSTALL routine. Is called before the driver is removed from memory. May
270 ; clean up anything done by INSTALL but is probably empty most of the time.
272 ; Must set an error code: NO
279 ; ------------------------------------------------------------------------
280 ; INIT: Changes an already installed device from text mode to graphics
282 ; Note that INIT/DONE may be called multiple times while the driver
283 ; is loaded, while INSTALL is only called once, so any code that is needed
284 ; to initializes variables and so on must go here. Setting palette and
285 ; clearing the screen is not needed because this is called by the graphics
287 ; The graphics kernel will never call INIT when a graphics mode is already
288 ; active, so there is no need to protect against that.
290 ; Must set an error code: YES
294 lda pages ; is there enough memory?
295 bne @L11 ; Jump if there is one screen
296 lda #TGI_ERR_INV_MODE ; ## Error
299 ; Initialize variables
304 ; Remeber current color value
309 ; Switch into graphics mode (set view page 0)
312 @L2: ldx InitVDCTab,y
321 ; Done, reset the error code
327 ; ------------------------------------------------------------------------
328 ; DONE: Will be called to switch the graphics device back into text mode.
329 ; The graphics kernel will never call DONE when no graphics mode is active,
330 ; so there is no need to protect against that.
332 ; Must set an error code: NO
336 ; This part is C128-mode specific
337 jsr $e179 ; reload character set and setup VDC
339 lda $d7 ; in 80-columns?
343 jsr $ffd2 ; print \xe,clr,\xe
347 jsr $ffd2 ; print clr
348 @L1: lda #0 ; restore view page
353 jsr VDCWriteReg ; restore color (background)
356 jmp VDCWriteReg ; switch to text screen
358 ; ------------------------------------------------------------------------
359 ; GETERROR: Return the error code in A and clear it.
367 ; ------------------------------------------------------------------------
368 ; CONTROL: Platform/driver specific entry point.
370 ; Must set an error code: YES
374 lda #TGI_ERR_INV_FUNC
378 ; ------------------------------------------------------------------------
379 ; CLEAR: Clears the screen.
381 ; Must set an error code: NO
390 jsr VDCWriteReg ; set fill mode
392 jsr VDCWriteByte ; put 1rst byte (fill value)
401 ; ------------------------------------------------------------------------
402 ; SETVIEWPAGE: Set the visible page. Called with the new page in A (0..n).
403 ; The page number is already checked to be valid by the graphics kernel.
405 ; Must set an error code: NO (will only be called if page ok)
411 ; ------------------------------------------------------------------------
412 ; SETDRAWPAGE: Set the drawable page. Called with the new page in A (0..n).
413 ; The page number is already checked to be valid by the graphics kernel.
415 ; Must set an error code: NO (will only be called if page ok)
421 ; ------------------------------------------------------------------------
422 ; SETCOLOR: Set the drawing color (in A). The new color is already checked
423 ; to be in a valid range (0..maxcolor-1).
425 ; Must set an error code: NO (will only be called if color ok)
435 ; ------------------------------------------------------------------------
436 ; SETPALETTE: Set the palette (not available with all drivers/hardware).
437 ; A pointer to the palette is passed in ptr1. Must set an error if palettes
440 ; Must set an error code: YES
445 @L1: lda (ptr1),y ; Copy the palette
446 and #$0F ; Make a valid color
451 ; Get the color entries from the palette
453 ldy PALETTE+1 ; Foreground color
459 ldy PALETTE ; Background color
464 lda #TGI_ERR_OK ; Clear error code
468 ; ------------------------------------------------------------------------
469 ; GETPALETTE: Return the current palette in A/X. Even drivers that cannot
470 ; set the palette should return the default palette here, so there's no
471 ; way for this function to fail.
473 ; Must set an error code: NO
481 ; ------------------------------------------------------------------------
482 ; GETDEFPALETTE: Return the default palette for the driver in A/X. All
483 ; drivers should return something reasonable here, even drivers that don't
484 ; support palettes, otherwise the caller has no way to determine the colors
485 ; of the (not changeable) palette.
487 ; Must set an error code: NO (all drivers must have a default palette)
495 ; ------------------------------------------------------------------------
496 ; SETPIXEL: Draw one pixel at X1/Y1 = ptr1/ptr2 with the current drawing
497 ; color. The coordinates passed to this function are never outside the
498 ; visible screen area, so there is no need for clipping inside this function.
500 ; Must set an error code: NO
515 jsr icmp ; if (xres<x1)
516 bcs @cont ; !(xres<x1)
525 jsr icmp ; if (yres<y1)
529 jsr CALC ; Calculate coordinates
551 ; ------------------------------------------------------------------------
552 ; GETPIXEL: Read the color value of a pixel and return it in A/X. The
553 ; coordinates passed to this function are never outside the visible screen
554 ; area, so there is no need for clipping inside this function.
558 jsr CALC ; Calculate coordinates
560 stx TEMP ; preserve X
572 @L1: tya ; Get color value into A
573 ldx #$00 ; Clear high byte
576 ; ------------------------------------------------------------------------
577 ; HORLINE: Draw a horizontal line from X1/Y to X2/Y, where X1 = ptr1,
578 ; Y = ptr2 and X2 = ptr3, using the current drawing color.
580 ; This is a special line drawing entry used when the line is know to be
581 ; horizontal, for example by the BAR emulation routine. If the driver does
582 ; not have special code for horizontal lines, it may just copy Y to Y2 and
583 ; proceed with the generic line drawing code.
585 ; Note: Line coordinates will always be sorted (Y1 <= X2) and clipped.
587 ; Must set an error code: NO
595 jsr CALC ; get data for LEFT
596 lda BITMASKL,x ; remember left address and bitmask
607 jsr CALC ; get data for RIGHT
611 pla ; recall data for LEFT
614 sta X1 ; put left address into X1
617 cmp #%11111111 ; if left bit <> 0
619 sta TEMP2 ; do left byte only...
634 inc X1 ; ... and proceed
638 ; do right byte (if Y2=0 ++ADDR and skip)
640 cmp #%11111111 ; if right bit <> 7
642 inc ADDR ; right bit = 7 - the next one is the last
647 @L11: lda ADDR ; do right byte only...
662 @L2: ; do the fill in the middle
663 lda ADDR ; calculate offset in full bytes
666 beq @L3 ; if equal - there are no more bytes
669 lda X1 ; setup for the left side
672 lda BITMASK ; get color
673 jsr VDCWriteByte ; put 1st value
676 beq @L3 ; 1 byte already written
678 stx ADDR ; if there are more bytes - fill them...
681 jsr VDCWriteReg ; setup for fill
684 jsr VDCWriteReg ; ... fill them NOW!
692 ; ------------------------------------------------------------------------
693 ; LINE: Draw a line from X1/Y1 to X2/Y2, where X1/Y1 = ptr1/ptr2 and
694 ; X2/Y2 = ptr3/ptr4 using the current drawing color.
696 ; Must set an error code: NO
786 ; for (count=nx;count>0;--count) {
791 @L0166: lda COUNT ; count>0
796 @L0167: jsr SETPIXELCLIP
836 ; if (abs(pb)<abs(ub)) {
852 ; } else { x1 = x1 + ay
891 ; ------------------------------------------------------------------------
892 ; BAR: Draw a filled rectangle with the corners X1/Y1, X2/Y2, where
893 ; X1/Y1 = ptr1/ptr2 and X2/Y2 = ptr3/ptr4 using the current drawing color.
894 ; Contrary to most other functions, the graphics kernel will sort and clip
895 ; the coordinates before calling the driver, so on entry the following
896 ; conditions are valid:
899 ; (X1 >= 0) && (X1 < XRES)
900 ; (X2 >= 0) && (X2 < XRES)
901 ; (Y1 >= 0) && (Y1 < YRES)
902 ; (Y2 >= 0) && (Y2 < YRES)
904 ; Must set an error code: NO
923 ; ------------------------------------------------------------------------
924 ; CIRCLE: Draw a circle around the center X1/Y1 (= ptr1/ptr2) with the
925 ; radius in tmp1 and the current drawing color.
927 ; Must set an error code: NO
933 jmp SETPIXELCLIP ; Plot as a point
951 stx YS+1 ; XS/YS to remember the center
960 @L12: ; plot points in 8 slices...
975 sta Y1+1 ; (stack)=ys+y, y1=(stack)
977 jsr SETPIXELCLIP ; plot(xs+x,ys+y)
985 sta Y1+1 ; y3 = y1 = ys-y
987 jsr SETPIXELCLIP ; plot(xs+x,ys-y)
999 jsr SETPIXELCLIP ; plot (xs-x,ys+y)
1004 jsr SETPIXELCLIP ; plot (xs-x,ys-y)
1012 sta X1+1 ; x1 = xs+y
1020 sta Y1+1 ; (stack)=ys+x, y1=(stack)
1022 jsr SETPIXELCLIP ; plot(xs+y,ys+x)
1030 sta Y1+1 ; y3 = y1 = ys-x
1032 jsr SETPIXELCLIP ; plot(xs+y,ys-x)
1036 sta Y1 ; y1 = ys+x(stack)
1044 jsr SETPIXELCLIP ; plot (xs-y,ys+x)
1049 jsr SETPIXELCLIP ; plot (xs-y,ys-x)
1099 @L0148: ; if (abs(ou)<abs(og))
1118 @L014E: ; mo = ou; }
1130 ; ------------------------------------------------------------------------
1131 ; TEXTSTYLE: Set the style used when calling OUTTEXT. Text scaling in X and Y
1132 ; direction is passend in X/Y, the text direction is passed in A.
1134 ; Must set an error code: NO
1144 ; ------------------------------------------------------------------------
1145 ; OUTTEXT: Output text at X/Y = ptr1/ptr2 using the current color and the
1146 ; current text style. The text to output is given as a zero terminated
1147 ; string with address in ptr3.
1149 ; Must set an error code: NO
1155 ; ------------------------------------------------------------------------
1156 ; Calculate all variables to plot the pixel at X1/Y1.
1157 ;------------------------
1159 ;> ADDR - address of card
1160 ;> X - bit number (X1 & 7)
1180 sta ADDR+1 ; Y*4+Y=Y*5
1190 sta ADDR ; Y*5*16=Y*80
1203 lda ADDR+1 ; ADDR = Y*80+x/8
1211 beq @even ; even line - no offset
1218 sta ADDR+1 ; odd lines are 21360 bytes farther
1225 ; copies of some runtime routines
1245 ; compare a/y to zp,x
1246 sta TEMP ; TEMP/TEMP2 - arg2
1254 tya ; x/a - arg1 (a=high)
1285 @L0: bit VDC_ADDR_REG
1294 @L0: bit VDC_ADDR_REG