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-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 API 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 .word $0100 ; Aspect ratio (based on 4/3 display)
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).
89 .addr 0 ; IRQ entry is unused
91 ; ------------------------------------------------------------------------
94 ; Variables mapped to the zero page segment variables. Some of these are
95 ; used for passing parameters to the driver.
104 TEMP2 = tmp4 ; HORLINE
105 TEMP3 = sreg ; HORLINE
107 ; Absolute variables used in the code
111 ERROR: .res 1 ; Error code
112 PALETTE: .res 2 ; The current palette
114 BITMASK: .res 1 ; $00 = clear, $FF = set pixels
116 OLDCOLOR: .res 1 ; colors before entering gfx mode
123 ; Constants and tables
127 DEFPALETTE: .byte $00, $0f ; White on black
128 PALETTESIZE = * - DEFPALETTE
130 BITTAB: .byte $80,$40,$20,$10,$08,$04,$02,$01
132 BITMASKL: .byte %11111111, %01111111, %00111111, %00011111
133 .byte %00001111, %00000111, %00000011, %00000001
135 BITMASKR: .byte %10000000, %11000000, %11100000, %11110000
136 .byte %11111000, %11111100, %11111110, %11111111
138 ; color translation table (indexed by VIC color)
139 COLTRANS: .byte $00, $0f, $08, $06, $0a, $04, $02, $0c
140 .byte $0d, $0b, $09, $01, $0e, $05, $03, $07
141 ; colors BROWN and GRAY3 are wrong
143 ; VDC initialization table (reg),(val),...,$ff
145 .byte VDC_DSP_HI, 0 ; viewpage 0 as default
147 .byte VDC_HSCROLL, $87
158 SCN80CLR: .byte 27,88,147,27,88,0
162 ; ------------------------------------------------------------------------
163 ; INSTALL routine. Is called after the driver is loaded into memory. May
164 ; initialize anything that has to be done just once. Is probably empty
167 ; Must set an error code: NO
171 ; check for VDC version and update register $19 value
173 ; check for VDC ram size and update number of available screens
175 ldx #VDC_CSET ; determine size of RAM...
179 jsr VDCWriteReg ; turn on 64k
181 jsr settestadr1 ; save original value of test byte
185 lda #$55 ; write $55 here
187 jsr test64k ; read it here and there
188 lda #$aa ; write $aa here
190 jsr test64k ; read it here and there
194 jsr VDCWriteByte ; restore original value of test byte
196 lda ptr1 ; do bytes match?
205 jsr VDCWriteReg ; restore 16/64k flag
206 jmp @endok ; and leave default values for 16k
221 jsr VDCWriteByte ; write $55
223 jsr VDCReadByte ; read here
226 jsr VDCReadByte ; and there
235 ldy #$02 ; test page 2 (here)
238 ldy #$42 ; or page 64+2 (there)
242 ; ------------------------------------------------------------------------
243 ; UNINSTALL routine. Is called before the driver is removed from memory. May
244 ; clean up anything done by INSTALL but is probably empty most of the time.
246 ; Must set an error code: NO
253 ; ------------------------------------------------------------------------
254 ; INIT: Changes an already installed device from text mode to graphics
256 ; Note that INIT/DONE may be called multiple times while the driver
257 ; is loaded, while INSTALL is only called once, so any code that is needed
258 ; to initializes variables and so on must go here. Setting palette and
259 ; clearing the screen is not needed because this is called by the graphics
261 ; The graphics kernel will never call INIT when a graphics mode is already
262 ; active, so there is no need to protect against that.
264 ; Must set an error code: YES
268 lda pages ; is there enough memory?
269 bne @L1 ; Jump if there is one screen
270 lda #TGI_ERR_INV_MODE ; Error
273 ; Initialize variables
278 ; Remeber current color value
283 ; Switch into graphics mode (set view page 0)
286 @L2: ldx InitVDCTab,y
295 ; Done, reset the error code
301 ; ------------------------------------------------------------------------
302 ; DONE: Will be called to switch the graphics device back into text mode.
303 ; The graphics kernel will never call DONE when no graphics mode is active,
304 ; so there is no need to protect against that.
306 ; Must set an error code: NO
310 ; This part is C128-mode specific
311 jsr $e179 ; reload character set and setup VDC
313 lda $d7 ; in 80-columns?
317 jsr $ffd2 ; print \xe,clr,\xe
321 jsr $ffd2 ; print clr
322 @L1: lda #0 ; restore view page
327 jsr VDCWriteReg ; restore color (background)
330 jmp VDCWriteReg ; switch to text screen
332 ; ------------------------------------------------------------------------
333 ; GETERROR: Return the error code in A and clear it.
341 ; ------------------------------------------------------------------------
342 ; CONTROL: Platform/driver specific entry point.
344 ; Must set an error code: YES
348 lda #TGI_ERR_INV_FUNC
352 ; ------------------------------------------------------------------------
353 ; CLEAR: Clears the screen.
355 ; Must set an error code: NO
364 jsr VDCWriteReg ; set fill mode
366 jsr VDCWriteByte ; put 1rst byte (fill value)
375 ; ------------------------------------------------------------------------
376 ; SETVIEWPAGE: Set the visible page. Called with the new page in A (0..n).
377 ; The page number is already checked to be valid by the graphics kernel.
379 ; Must set an error code: NO (will only be called if page ok)
385 ; ------------------------------------------------------------------------
386 ; SETDRAWPAGE: Set the drawable page. Called with the new page in A (0..n).
387 ; The page number is already checked to be valid by the graphics kernel.
389 ; Must set an error code: NO (will only be called if page ok)
395 ; ------------------------------------------------------------------------
396 ; SETCOLOR: Set the drawing color (in A). The new color is already checked
397 ; to be in a valid range (0..maxcolor-1).
399 ; Must set an error code: NO (will only be called if color ok)
409 ; ------------------------------------------------------------------------
410 ; SETPALETTE: Set the palette (not available with all drivers/hardware).
411 ; A pointer to the palette is passed in ptr1. Must set an error if palettes
414 ; Must set an error code: YES
419 @L1: lda (ptr1),y ; Copy the palette
420 and #$0F ; Make a valid color
425 ; Get the color entries from the palette
427 ldy PALETTE+1 ; Foreground color
433 ldy PALETTE ; Background color
438 lda #TGI_ERR_OK ; Clear error code
442 ; ------------------------------------------------------------------------
443 ; GETPALETTE: Return the current palette in A/X. Even drivers that cannot
444 ; set the palette should return the default palette here, so there's no
445 ; way for this function to fail.
447 ; Must set an error code: NO
455 ; ------------------------------------------------------------------------
456 ; GETDEFPALETTE: Return the default palette for the driver in A/X. All
457 ; drivers should return something reasonable here, even drivers that don't
458 ; support palettes, otherwise the caller has no way to determine the colors
459 ; of the (not changeable) palette.
461 ; Must set an error code: NO (all drivers must have a default palette)
469 ; ------------------------------------------------------------------------
470 ; SETPIXEL: Draw one pixel at X1/Y1 = ptr1/ptr2 with the current drawing
471 ; color. The coordinates passed to this function are never outside the
472 ; visible screen area, so there is no need for clipping inside this function.
474 ; Must set an error code: NO
478 jsr CALC ; Calculate coordinates
500 ; ------------------------------------------------------------------------
501 ; GETPIXEL: Read the color value of a pixel and return it in A/X. The
502 ; coordinates passed to this function are never outside the visible screen
503 ; area, so there is no need for clipping inside this function.
507 jsr CALC ; Calculate coordinates
509 stx TEMP ; preserve X
521 @L1: tya ; Get color value into A
522 ldx #$00 ; Clear high byte
525 ; ------------------------------------------------------------------------
526 ; BAR: Draw a filled rectangle with the corners X1/Y1, X2/Y2, where
527 ; X1/Y1 = ptr1/ptr2 and X2/Y2 = ptr3/ptr4 using the current drawing color.
528 ; Contrary to most other functions, the graphics kernel will sort and clip
529 ; the coordinates before calling the driver, so on entry the following
530 ; conditions are valid:
533 ; (X1 >= 0) && (X1 < XRES)
534 ; (X2 >= 0) && (X2 < XRES)
535 ; (Y1 >= 0) && (Y1 < YRES)
536 ; (Y2 >= 0) && (Y2 < YRES)
538 ; Must set an error code: NO
546 ; Original code for a horizontal line
553 jsr CALC ; get data for LEFT
554 lda BITMASKL,x ; remember left address and bitmask
565 jsr CALC ; get data for RIGHT
569 pla ; recall data for LEFT
572 sta X1 ; put left address into X1
575 cmp #%11111111 ; if left bit <> 0
577 sta TEMP2 ; do left byte only...
592 inc X1 ; ... and proceed
596 ; do right byte (if Y2=0 ++ADDR and skip)
598 cmp #%11111111 ; if right bit <> 7
600 inc ADDR ; right bit = 7 - the next one is the last
605 @L11: lda ADDR ; do right byte only...
620 @L2: ; do the fill in the middle
621 lda ADDR ; calculate offset in full bytes
624 beq @L3 ; if equal - there are no more bytes
627 lda X1 ; setup for the left side
630 lda BITMASK ; get color
631 jsr VDCWriteByte ; put 1st value
634 beq @L3 ; 1 byte already written
636 stx ADDR ; if there are more bytes - fill them...
639 jsr VDCWriteReg ; setup for fill
642 jsr VDCWriteReg ; ... fill them NOW!
649 ; End of horizontal line code
665 ; ------------------------------------------------------------------------
666 ; TEXTSTYLE: Set the style used when calling OUTTEXT. Text scaling in X and Y
667 ; direction is passend in X/Y, the text direction is passed in A.
669 ; Must set an error code: NO
679 ; ------------------------------------------------------------------------
680 ; OUTTEXT: Output text at X/Y = ptr1/ptr2 using the current color and the
681 ; current text style. The text to output is given as a zero terminated
682 ; string with address in ptr3.
684 ; Must set an error code: NO
690 ; ------------------------------------------------------------------------
691 ; Calculate all variables to plot the pixel at X1/Y1.
692 ;------------------------
694 ;> ADDR - address of card
695 ;> X - bit number (X1 & 7)
715 sta ADDR+1 ; Y*4+Y=Y*5
725 sta ADDR ; Y*5*16=Y*80
738 lda ADDR+1 ; ADDR = Y*80+x/8
746 beq @even ; even line - no offset
753 sta ADDR+1 ; odd lines are 21360 bytes farther
775 @L0: bit VDC_ADDR_REG
784 @L0: bit VDC_ADDR_REG
789 ; ------------------------------------------------------------------------
791 .include "../tgi/tgidrv_line.inc"