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>
6 ; 2004-04-04, Greg King
9 ; For any smart monkey that will try to optimize this: PLEASE do tests on
10 ; real VDC, not only VICE.
12 ; Only DONE routine contains C128-mode specific stuff, everything else will
13 ; work in C64-mode of C128 (C64 needs full VDC init then).
15 ; With special initialization and CALC we can get 320x200 double-pixel mode.
17 ; Color translation values for BROWN and GRAY3 are obviously wrong, they
18 ; could be replaced by equiv. of ORANGE and GRAY2 but this would give only
19 ; 14 of 16 colors available.
21 ; Register 25 ($19) is said to require different value for VDC v1, but I
22 ; couldn't find what it should be.
24 .include "zeropage.inc"
26 .include "tgi-kernel.inc"
27 .include "tgi-mode.inc"
28 .include "tgi-error.inc"
33 ; ------------------------------------------------------------------------
36 VDC_ADDR_REG = $D600 ; VDC address
37 VDC_DATA_REG = $D601 ; VDC data
39 VDC_DSP_HI = 12 ; registers used
50 ; ------------------------------------------------------------------------
51 ; Header. Includes jump table and constants.
55 ; First part of the header is a structure that has a magic and defines the
56 ; capabilities of the driver
58 .byte $74, $67, $69 ; "tgi"
59 .byte TGI_API_VERSION ; TGI API version number
60 xres: .word 640 ; X resolution
61 yres: .word 480 ; Y resolution
62 .byte 2 ; Number of drawing colors
63 pages: .byte 0 ; Number of screens available
64 .byte 8 ; System font X size
65 .byte 8 ; System font Y size
66 .word $0100 ; Aspect ratio (based on 4/3 display)
68 ; Next comes the jump table. Currently all entries must be valid and may point
69 ; to an RTS for test versions (function not implemented).
90 .addr 0 ; IRQ entry is unused
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 ERROR: .res 1 ; Error code
113 PALETTE: .res 2 ; The current palette
115 BITMASK: .res 1 ; $00 = clear, $FF = set pixels
117 OLDCOLOR: .res 1 ; colors before entering gfx mode
124 ; Constants and tables
128 DEFPALETTE: .byte $00, $0f ; White on black
129 PALETTESIZE = * - DEFPALETTE
131 BITTAB: .byte $80,$40,$20,$10,$08,$04,$02,$01
133 BITMASKL: .byte %11111111, %01111111, %00111111, %00011111
134 .byte %00001111, %00000111, %00000011, %00000001
136 BITMASKR: .byte %10000000, %11000000, %11100000, %11110000
137 .byte %11111000, %11111100, %11111110, %11111111
139 ; color translation table (indexed by VIC color)
140 COLTRANS: .byte $00, $0f, $08, $06, $0a, $04, $02, $0c
141 .byte $0d, $0b, $09, $01, $0e, $05, $03, $07
142 ; colors BROWN and GRAY3 are wrong
144 ; VDC initialization table (reg),(val),...,$ff
146 .byte VDC_DSP_HI, 0 ; viewpage 0 as default
148 .byte VDC_HSCROLL, $87
159 SCN80CLR: .byte 27,88,147,27,88,0
163 ; ------------------------------------------------------------------------
164 ; INSTALL routine. Is called after the driver is loaded into memory. May
165 ; initialize anything that has to be done just once. Is probably empty
168 ; Must set an error code: NO
172 ; check for VDC version and update register $19 value
174 ; check for VDC ram size and update number of available screens
176 ldx #VDC_CSET ; determine size of RAM...
180 jsr VDCWriteReg ; turn on 64k
182 jsr settestadr1 ; save original value of test byte
186 lda #$55 ; write $55 here
188 jsr test64k ; read it here and there
189 lda #$aa ; write $aa here
191 jsr test64k ; read it here and there
195 jsr VDCWriteByte ; restore original value of test byte
197 lda ptr1 ; do bytes match?
206 jsr VDCWriteReg ; restore 16/64k flag
207 jmp @endok ; and leave default values for 16k
222 jsr VDCWriteByte ; write $55
224 jsr VDCReadByte ; read here
227 jsr VDCReadByte ; and there
236 ldy #$02 ; test page 2 (here)
239 ldy #$42 ; or page 64+2 (there)
243 ; ------------------------------------------------------------------------
244 ; UNINSTALL routine. Is called before the driver is removed from memory. May
245 ; clean up anything done by INSTALL but is probably empty most of the time.
247 ; Must set an error code: NO
254 ; ------------------------------------------------------------------------
255 ; INIT: Changes an already installed device from text mode to graphics
257 ; Note that INIT/DONE may be called multiple times while the driver
258 ; is loaded, while INSTALL is only called once, so any code that is needed
259 ; to initializes variables and so on must go here. Setting palette and
260 ; clearing the screen is not needed because this is called by the graphics
262 ; The graphics kernel will never call INIT when a graphics mode is already
263 ; active, so there is no need to protect against that.
265 ; Must set an error code: YES
269 lda pages ; is there enough memory?
270 bne @L1 ; Jump if there is one screen
271 lda #TGI_ERR_INV_MODE ; Error
274 ; Initialize variables
279 ; Remeber current color value
284 ; Switch into graphics mode (set view page 0)
287 @L2: ldx InitVDCTab,y
296 ; Done, reset the error code
302 ; ------------------------------------------------------------------------
303 ; DONE: Will be called to switch the graphics device back into text mode.
304 ; The graphics kernel will never call DONE when no graphics mode is active,
305 ; so there is no need to protect against that.
307 ; Must set an error code: NO
311 ; This part is C128-mode specific
312 jsr $e179 ; reload character set and setup VDC
314 lda $d7 ; in 80-columns?
318 jsr $ffd2 ; print \xe,clr,\xe
322 jsr $ffd2 ; print clr
323 @L1: lda #0 ; restore view page
328 jsr VDCWriteReg ; restore color (background)
331 jmp VDCWriteReg ; switch to text screen
333 ; ------------------------------------------------------------------------
334 ; GETERROR: Return the error code in A and clear it.
342 ; ------------------------------------------------------------------------
343 ; CONTROL: Platform/driver specific entry point.
345 ; Must set an error code: YES
349 lda #TGI_ERR_INV_FUNC
353 ; ------------------------------------------------------------------------
354 ; CLEAR: Clears the screen.
356 ; Must set an error code: NO
365 jsr VDCWriteReg ; set fill mode
367 jsr VDCWriteByte ; put 1rst byte (fill value)
376 ; ------------------------------------------------------------------------
377 ; SETVIEWPAGE: Set the visible page. Called with the new page in A (0..n).
378 ; The page number is already checked to be valid by the graphics kernel.
380 ; Must set an error code: NO (will only be called if page ok)
386 ; ------------------------------------------------------------------------
387 ; SETDRAWPAGE: Set the drawable page. Called with the new page in A (0..n).
388 ; The page number is already checked to be valid by the graphics kernel.
390 ; Must set an error code: NO (will only be called if page ok)
396 ; ------------------------------------------------------------------------
397 ; SETCOLOR: Set the drawing color (in A). The new color is already checked
398 ; to be in a valid range (0..maxcolor-1).
400 ; Must set an error code: NO (will only be called if color ok)
410 ; ------------------------------------------------------------------------
411 ; SETPALETTE: Set the palette (not available with all drivers/hardware).
412 ; A pointer to the palette is passed in ptr1. Must set an error if palettes
415 ; Must set an error code: YES
420 @L1: lda (ptr1),y ; Copy the palette
421 and #$0F ; Make a valid color
426 ; Get the color entries from the palette
428 ldy PALETTE+1 ; Foreground color
434 ldy PALETTE ; Background color
439 lda #TGI_ERR_OK ; Clear error code
443 ; ------------------------------------------------------------------------
444 ; GETPALETTE: Return the current palette in A/X. Even drivers that cannot
445 ; set the palette should return the default palette here, so there's no
446 ; way for this function to fail.
448 ; Must set an error code: NO
456 ; ------------------------------------------------------------------------
457 ; GETDEFPALETTE: Return the default palette for the driver in A/X. All
458 ; drivers should return something reasonable here, even drivers that don't
459 ; support palettes, otherwise the caller has no way to determine the colors
460 ; of the (not changeable) palette.
462 ; Must set an error code: NO (all drivers must have a default palette)
470 ; ------------------------------------------------------------------------
471 ; SETPIXEL: Draw one pixel at X1/Y1 = ptr1/ptr2 with the current drawing
472 ; color. The coordinates passed to this function are never outside the
473 ; visible screen area, so there is no need for clipping inside this function.
475 ; Must set an error code: NO
479 jsr CALC ; Calculate coordinates
501 ; ------------------------------------------------------------------------
502 ; GETPIXEL: Read the color value of a pixel and return it in A/X. The
503 ; coordinates passed to this function are never outside the visible screen
504 ; area, so there is no need for clipping inside this function.
508 jsr CALC ; Calculate coordinates
510 stx TEMP ; preserve X
522 @L1: tya ; Get color value into A
523 ldx #$00 ; Clear high byte
526 ; ------------------------------------------------------------------------
527 ; BAR: Draw a filled rectangle with the corners X1/Y1, X2/Y2, where
528 ; X1/Y1 = ptr1/ptr2 and X2/Y2 = ptr3/ptr4 using the current drawing color.
529 ; Contrary to most other functions, the graphics kernel will sort and clip
530 ; the coordinates before calling the driver, so on entry the following
531 ; conditions are valid:
534 ; (X1 >= 0) && (X1 < XRES)
535 ; (X2 >= 0) && (X2 < XRES)
536 ; (Y1 >= 0) && (Y1 < YRES)
537 ; (Y2 >= 0) && (Y2 < YRES)
539 ; Must set an error code: NO
547 ; Original code for a horizontal line
554 jsr CALC ; get data for LEFT
555 lda BITMASKL,x ; remember left address and bitmask
566 jsr CALC ; get data for RIGHT
570 pla ; recall data for LEFT
573 sta X1 ; put left address into X1
576 cmp #%11111111 ; if left bit <> 0
578 sta TEMP2 ; do left byte only...
593 inc X1 ; ... and proceed
597 ; do right byte (if Y2=0 ++ADDR and skip)
599 cmp #%11111111 ; if right bit <> 7
601 inc ADDR ; right bit = 7 - the next one is the last
606 @L11: lda ADDR ; do right byte only...
621 @L2: ; do the fill in the middle
622 lda ADDR ; calculate offset in full bytes
625 beq @L3 ; if equal - there are no more bytes
628 lda X1 ; setup for the left side
631 lda BITMASK ; get color
632 jsr VDCWriteByte ; put 1st value
635 beq @L3 ; 1 byte already written
637 stx ADDR ; if there are more bytes - fill them...
640 jsr VDCWriteReg ; setup for fill
643 jsr VDCWriteReg ; ... fill them NOW!
650 ; End of horizontal line code
666 ; ------------------------------------------------------------------------
667 ; TEXTSTYLE: Set the style used when calling OUTTEXT. Text scaling in X and Y
668 ; direction is passend in X/Y, the text direction is passed in A.
670 ; Must set an error code: NO
680 ; ------------------------------------------------------------------------
681 ; OUTTEXT: Output text at X/Y = ptr1/ptr2 using the current color and the
682 ; current text style. The text to output is given as a zero terminated
683 ; string with address in ptr3.
685 ; Must set an error code: NO
691 ; ------------------------------------------------------------------------
692 ; Calculate all variables to plot the pixel at X1/Y1.
693 ;------------------------
695 ;> ADDR - address of card
696 ;> X - bit number (X1 & 7)
716 sta ADDR+1 ; Y*4+Y=Y*5
726 sta ADDR ; Y*5*16=Y*80
739 lda ADDR+1 ; ADDR = Y*80+x/8
747 beq @even ; even line - no offset
754 sta ADDR+1 ; odd lines are 21360 bytes farther
776 @L0: bit VDC_ADDR_REG
785 @L0: bit VDC_ADDR_REG
790 ; ------------------------------------------------------------------------
792 .include "../tgi/tgidrv_line.inc"