2 ; Graphics driver for the 640x200x2 mode on the C128 VDC
3 ; Maciej 'YTM/Elysium' Witkowiak <ytm@elysium.pl>
5 ; 2004-04-04, Greg King
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-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.
52 module_header _c128_vdc_tgi
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 API version number
59 .addr $0000 ; Library reference
60 xres: .word 640 ; X resolution
61 yres: .word 200 ; Y resolution
62 .byte 2 ; Number of drawing colors
63 pages: .byte 1 ; Number of screens available
64 .byte 8 ; System font X size
65 .byte 8 ; System font Y size
66 .word $006A ; Aspect ratio (based on 4/3 display)
67 .byte 0 ; TGI driver flags
69 ; Next comes the jump table. Currently all entries must be valid and may point
70 ; 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.
105 TEMP2 = tmp4 ; HORLINE
106 TEMP3 = sreg ; HORLINE
108 ; Absolute variables used in the code
112 SCRBASE: .res 1 ; High byte of screen base
114 ERROR: .res 1 ; Error code
115 PALETTE: .res 2 ; The current palette
117 BITMASK: .res 1 ; $00 = clear, $FF = set pixels
119 OLDCOLOR: .res 1 ; colors before entering gfx mode
126 ; Constants and tables
130 DEFPALETTE: .byte $00, $0f ; White on black
131 PALETTESIZE = * - DEFPALETTE
133 BITTAB: .byte $80,$40,$20,$10,$08,$04,$02,$01
135 BITMASKL: .byte %11111111, %01111111, %00111111, %00011111
136 .byte %00001111, %00000111, %00000011, %00000001
138 BITMASKR: .byte %10000000, %11000000, %11100000, %11110000
139 .byte %11111000, %11111100, %11111110, %11111111
141 ; color translation table (indexed by VIC color)
142 COLTRANS: .byte $00, $0f, $08, $06, $0a, $04, $02, $0c
143 .byte $0d, $0b, $09, $01, $0e, $05, $03, $07
144 ; colors BROWN and GRAY3 are wrong
146 ; VDC initialization table (reg),(val),...,$ff
148 .byte VDC_DSP_HI, 0 ; viewpage 0 as default
150 .byte VDC_HSCROLL, $87
153 SCN80CLR: .byte 27,88,147,27,88,0
157 ; ------------------------------------------------------------------------
158 ; INSTALL routine. Is called after the driver is loaded into memory. May
159 ; initialize anything that has to be done just once. Is probably empty
162 ; Must set an error code: NO
166 ; check for VDC version and update register $19 value
168 ; check for VDC ram size and update number of available screens
170 ldx #VDC_CSET ; determine size of RAM...
174 jsr VDCWriteReg ; turn on 64k
176 jsr settestadr1 ; save original value of test byte
180 lda #$55 ; write $55 here
182 jsr test64k ; read it here and there
183 lda #$aa ; write $aa here
185 jsr test64k ; read it here and there
189 jsr VDCWriteByte ; restore original value of test byte
191 lda ptr1 ; do bytes match?
200 jsr VDCWriteReg ; restore 16/64k flag
201 jmp @endok ; and leave default values for 16k
208 sta SCRBASE ; draw page 0 as default
218 jsr VDCWriteByte ; write $55
220 jsr VDCReadByte ; read here
223 jsr VDCReadByte ; and there
232 ldy #$02 ; test page 2 (here)
235 ldy #$42 ; or page 64+2 (there)
239 ; ------------------------------------------------------------------------
240 ; UNINSTALL routine. Is called before the driver is removed from memory. May
241 ; clean up anything done by INSTALL but is probably empty most of the time.
243 ; Must set an error code: NO
250 ; ------------------------------------------------------------------------
251 ; INIT: Changes an already installed device from text mode to graphics
253 ; Note that INIT/DONE may be called multiple times while the driver
254 ; is loaded, while INSTALL is only called once, so any code that is needed
255 ; to initializes variables and so on must go here. Setting palette and
256 ; clearing the screen is not needed because this is called by the graphics
258 ; The graphics kernel will never call INIT when a graphics mode is already
259 ; active, so there is no need to protect against that.
261 ; Must set an error code: YES
266 ; Initialize variables
271 ; Remeber current color value
276 ; Switch into graphics mode (set view page 0)
279 @L2: ldx InitVDCTab,y
288 ; Done, reset the error code
294 ; ------------------------------------------------------------------------
295 ; DONE: Will be called to switch the graphics device back into text mode.
296 ; The graphics kernel will never call DONE when no graphics mode is active,
297 ; so there is no need to protect against that.
299 ; Must set an error code: NO
303 ; This part is C128-mode specific
304 jsr $e179 ; reload character set and setup VDC
306 lda $d7 ; in 80-columns?
310 jsr $ffd2 ; print \xe,clr,\xe
314 jsr $ffd2 ; print clr
315 @L1: lda #0 ; restore view page
320 jsr VDCWriteReg ; restore color (background)
323 jmp VDCWriteReg ; switch to text screen
325 ; ------------------------------------------------------------------------
326 ; GETERROR: Return the error code in A and clear it.
334 ; ------------------------------------------------------------------------
335 ; CONTROL: Platform/driver specific entry point.
337 ; Must set an error code: YES
341 lda #TGI_ERR_INV_FUNC
345 ; ------------------------------------------------------------------------
346 ; CLEAR: Clears the screen.
348 ; Must set an error code: NO
357 jsr VDCWriteReg ; set fill mode
359 jsr VDCWriteByte ; put 1rst byte (fill value)
367 jmp VDCWriteReg ; 1+62*256+127=16000=(640*256)/8
369 ; ------------------------------------------------------------------------
370 ; SETVIEWPAGE: Set the visible page. Called with the new page in A (0..n).
371 ; The page number is already checked to be valid by the graphics kernel.
373 ; Must set an error code: NO (will only be called if page ok)
384 ; ------------------------------------------------------------------------
385 ; SETDRAWPAGE: Set the drawable page. Called with the new page in A (0..n).
386 ; The page number is already checked to be valid by the graphics kernel.
388 ; Must set an error code: NO (will only be called if page ok)
399 ; ------------------------------------------------------------------------
400 ; SETCOLOR: Set the drawing color (in A). The new color is already checked
401 ; to be in a valid range (0..maxcolor-1).
403 ; Must set an error code: NO (will only be called if color ok)
413 ; ------------------------------------------------------------------------
414 ; SETPALETTE: Set the palette (not available with all drivers/hardware).
415 ; A pointer to the palette is passed in ptr1. Must set an error if palettes
418 ; Must set an error code: YES
423 @L1: lda (ptr1),y ; Copy the palette
424 and #$0F ; Make a valid color
429 ; Get the color entries from the palette
431 ldy PALETTE+1 ; Foreground color
437 ldy PALETTE ; Background color
442 lda #TGI_ERR_OK ; Clear error code
446 ; ------------------------------------------------------------------------
447 ; GETPALETTE: Return the current palette in A/X. Even drivers that cannot
448 ; set the palette should return the default palette here, so there's no
449 ; way for this function to fail.
451 ; Must set an error code: NO
459 ; ------------------------------------------------------------------------
460 ; GETDEFPALETTE: Return the default palette for the driver in A/X. All
461 ; drivers should return something reasonable here, even drivers that don't
462 ; support palettes, otherwise the caller has no way to determine the colors
463 ; of the (not changeable) palette.
465 ; Must set an error code: NO (all drivers must have a default palette)
473 ; ------------------------------------------------------------------------
474 ; SETPIXEL: Draw one pixel at X1/Y1 = ptr1/ptr2 with the current drawing
475 ; color. The coordinates passed to this function are never outside the
476 ; visible screen area, so there is no need for clipping inside this function.
478 ; Must set an error code: NO
482 jsr CALC ; Calculate coordinates
504 ; ------------------------------------------------------------------------
505 ; GETPIXEL: Read the color value of a pixel and return it in A/X. The
506 ; coordinates passed to this function are never outside the visible screen
507 ; area, so there is no need for clipping inside this function.
511 jsr CALC ; Calculate coordinates
513 stx TEMP ; preserve X
525 @L1: tya ; Get color value into A
526 ldx #$00 ; Clear high byte
529 ; ------------------------------------------------------------------------
530 ; BAR: Draw a filled rectangle with the corners X1/Y1, X2/Y2, where
531 ; X1/Y1 = ptr1/ptr2 and X2/Y2 = ptr3/ptr4 using the current drawing color.
532 ; Contrary to most other functions, the graphics kernel will sort and clip
533 ; the coordinates before calling the driver, so on entry the following
534 ; conditions are valid:
537 ; (X1 >= 0) && (X1 < XRES)
538 ; (X2 >= 0) && (X2 < XRES)
539 ; (Y1 >= 0) && (Y1 < YRES)
540 ; (Y2 >= 0) && (Y2 < YRES)
542 ; Must set an error code: NO
550 ; Original code for a horizontal line
557 jsr CALC ; get data for LEFT
558 lda BITMASKL,x ; remember left address and bitmask
569 jsr CALC ; get data for RIGHT
573 pla ; recall data for LEFT
576 sta X1 ; put left address into X1
579 cmp #%11111111 ; if left bit <> 0
581 sta TEMP2 ; do left byte only...
596 inc X1 ; ... and proceed
600 ; do right byte (if Y2=0 ++ADDR and skip)
602 cmp #%11111111 ; if right bit <> 7
604 inc ADDR ; right bit = 7 - the next one is the last
609 @L11: lda ADDR ; do right byte only...
624 @L2: ; do the fill in the middle
625 lda ADDR ; calculate offset in full bytes
628 beq @L3 ; if equal - there are no more bytes
631 lda X1 ; setup for the left side
634 lda BITMASK ; get color
635 jsr VDCWriteByte ; put 1st value
638 beq @L3 ; 1 byte already written
640 stx ADDR ; if there are more bytes - fill them...
643 jsr VDCWriteReg ; setup for fill
646 jsr VDCWriteReg ; ... fill them NOW!
653 ; End of horizontal line code
669 ; ------------------------------------------------------------------------
670 ; TEXTSTYLE: Set the style used when calling OUTTEXT. Text scaling in X and Y
671 ; direction is passend in X/Y, the text direction is passed in A.
673 ; Must set an error code: NO
683 ; ------------------------------------------------------------------------
684 ; OUTTEXT: Output text at X/Y = ptr1/ptr2 using the current color and the
685 ; current text style. The text to output is given as a zero terminated
686 ; string with address in ptr3.
688 ; Must set an error code: NO
694 ; ------------------------------------------------------------------------
695 ; Calculate all variables to plot the pixel at X1/Y1.
696 ;------------------------
698 ;> ADDR - address of card
699 ;> X - bit number (X1 & 7)
713 sta ADDR+1 ; Y*4+Y=Y*5
723 sta ADDR ; Y*5*16=Y*80
736 lda ADDR+1 ; ADDR = Y*80+x/8
763 @L0: bit VDC_ADDR_REG
772 @L0: bit VDC_ADDR_REG
777 ; ------------------------------------------------------------------------
779 .include "../../tgi/tgidrv_line.inc"