2 ; Graphics driver for the 40x48x16 mode on the Apple II
4 ; Stefan Haubenthal <polluks@sdf.lonestar.org>
5 ; Oliver Schmidt <ol.sc@web.de>
8 .include "zeropage.inc"
10 .include "tgi-kernel.inc"
11 .include "tgi-error.inc"
14 ; ------------------------------------------------------------------------
32 ; Used for passing parameters to the driver
39 ; ------------------------------------------------------------------------
43 ; Header. Includes jump table and constants.
45 ; First part of the header is a structure that has a magic and defines the
46 ; capabilities of the driver
48 .byte $74, $67, $69 ; "tgi"
49 .byte TGI_API_VERSION ; TGI API version number
50 .word 40 ; X resolution
51 .word 48 ; Y resolution
52 .byte 16 ; Number of drawing colors
53 .byte 1 ; Number of screens available
54 .byte 8 ; System font X size
55 .byte 8 ; System font Y size
56 .word $0198 ; Aspect ratio (based on 4/3 display)
58 ; Next comes the jump table. With the exception of IRQ, all entries must be
59 ; valid and may point to an RTS for test versions (function not implemented).
80 .addr 0 ; IRQ entry is unused
82 ; ------------------------------------------------------------------------
86 ERROR: .res 1 ; Error code
87 MIX: .res 1 ; 4 lines of text
89 ; ------------------------------------------------------------------------
93 DEFPALETTE: .byte $00, $01, $02, $03, $04, $05, $06, $07
94 .byte $08, $09, $0A, $0B, $0C, $0D, $0E, $0F
96 TGI2COL: .byte $00, $0C, $03, $0F, $01, $09, $06, $02
97 .byte $04, $05, $07, $08, $0A, $0B, $0D, $0E
99 COL2TGI: .byte $00, $04, $07, $02, $08, $09, $06, $0A
100 .byte $0B, $05, $0C, $0D, $01, $0E, $0F, $03
104 ; ------------------------------------------------------------------------
108 ; INIT: Changes an already installed device from text mode to graphics mode.
109 ; Note that INIT/DONE may be called multiple times while the driver
110 ; is loaded, while INSTALL is only called once, so any code that is needed
111 ; to initializes variables and so on must go here. Setting palette and
112 ; clearing the screen is not needed because this is called by the graphics
114 ; The graphics kernel will never call INIT when a graphics mode is already
115 ; active, so there is no need to protect against that.
116 ; Must set an error code: YES
118 ; Switch into graphics mode
119 bit $C082 ; Switch in ROM
122 bit $C080 ; Switch in LC bank 2 for R/O
124 ; Done, reset the error code
131 ; INSTALL routine. Is called after the driver is loaded into memory. May
132 ; initialize anything that has to be done just once. Is probably empty
134 ; Must set an error code: NO
138 ; UNINSTALL routine. Is called before the driver is removed from memory. May
139 ; clean up anything done by INSTALL but is probably empty most of the time.
140 ; Must set an error code: NO
144 ; SETVIEWPAGE: Set the visible page. Called with the new page in A (0..n).
145 ; The page number is already checked to be valid by the graphics kernel.
146 ; Must set an error code: NO (will only be called if page ok)
150 ; SETDRAWPAGE: Set the drawable page. Called with the new page in A (0..n).
151 ; The page number is already checked to be valid by the graphics kernel.
152 ; Must set an error code: NO (will only be called if page ok)
156 ; TEXTSTYLE: Set the style used when calling OUTTEXT. Text scaling in X and Y
157 ; direction is passend in X/Y, the text direction is passed in A.
158 ; Must set an error code: NO
162 ; OUTTEXT: Output text at X/Y = ptr1/ptr2 using the current color and the
163 ; current text style. The text to output is given as a zero terminated
164 ; string with address in ptr3.
165 ; Must set an error code: NO
169 ; DONE: Will be called to switch the graphics device back into text mode.
170 ; The graphics kernel will never call DONE when no graphics mode is active,
171 ; so there is no need to protect against that.
172 ; Must set an error code: NO
174 bit $C082 ; Switch in ROM
177 bit $C080 ; Switch in LC bank 2 for R/O
180 ; GETERROR: Return the error code in A and clear it.
187 ; CLEAR: Clears the screen.
188 ; Must set an error code: NO
190 bit $C082 ; Switch in ROM
191 lda COLOR ; Save current drawing color
194 ldy MAXY,x ; Max Y depends on 4 lines of text
197 sta COLOR ; Restore current drawing color
198 bit $C080 ; Switch in LC bank 2 for R/O
201 ; SETCOLOR: Set the drawing color (in A). The new color is already checked
202 ; to be in a valid range (0..maxcolor-1).
203 ; Must set an error code: NO (will only be called if color ok)
205 bit $C082 ; Switch in ROM
209 bit $C080 ; Switch in LC bank 2 for R/O
212 ; CONTROL: Platform/driver specific entry point.
213 ; Must set an error code: YES
215 ; Check data msb and code to be 0
219 ; Check data lsb to be [0..1]
223 bit $C082 ; Switch in ROM
225 ; Switch 4 lines of text
227 .assert MIXCLR + 1 = MIXSET, error
228 lda MIXCLR,x ; No BIT absolute,X available
230 ; Save current switch setting
235 ; Clear 8 lines of graphics
236 lda COLOR ; Save current drawing color
238 lda #39 ; Rightmost column
242 ldy #$00 ; Leftmost column
244 jsr HLINE ; Preserves X
246 cpx #47+1 ; Last line
249 sta COLOR ; Restore current drawing color
250 bcs :+ ; Branch always
252 ; Clear 4 lines of text
254 : bit $C080 ; Switch in LC bank 2 for R/O
256 ; Done, reset the error code
258 beq :+ ; Branch always
260 ; Done, set the error code
261 err: lda #TGI_ERR_INV_ARG
265 ; SETPALETTE: Set the palette (not available with all drivers/hardware).
266 ; A pointer to the palette is passed in ptr1. Must set an error if palettes
268 ; Must set an error code: YES
270 lda #TGI_ERR_INV_FUNC
274 ; GETPALETTE: Return the current palette in A/X. Even drivers that cannot
275 ; set the palette should return the default palette here, so there's no
276 ; way for this function to fail.
277 ; Must set an error code: NO
281 ; GETDEFPALETTE: Return the default palette for the driver in A/X. All
282 ; drivers should return something reasonable here, even drivers that don't
283 ; support palettes, otherwise the caller has no way to determine the colors
284 ; of the (not changeable) palette.
285 ; Must set an error code: NO (all drivers must have a default palette)
291 ; SETPIXEL: Draw one pixel at X1/Y1 = ptr1/ptr2 with the current drawing
292 ; color. The coordinates passed to this function are never outside the
293 ; visible screen area, so there is no need for clipping inside this function.
294 ; Must set an error code: NO
296 bit $C082 ; Switch in ROM
300 bit $C080 ; Switch in LC bank 2 for R/O
303 ; GETPIXEL: Read the color value of a pixel and return it in A/X. The
304 ; coordinates passed to this function are never outside the visible screen
305 ; area, so there is no need for clipping inside this function.
307 bit $C082 ; Switch in ROM
314 bit $C080 ; Switch in LC bank 2 for R/O
317 ; BAR: Draw a filled rectangle with the corners X1/Y1, X2/Y2, where
318 ; X1/Y1 = ptr1/ptr2 and X2/Y2 = ptr3/ptr4 using the current drawing color.
319 ; Contrary to most other functions, the graphics kernel will sort and clip
320 ; the coordinates before calling the driver, so on entry the following
321 ; conditions are valid:
324 ; (X1 >= 0) && (X1 < XRES)
325 ; (X2 >= 0) && (X2 < XRES)
326 ; (Y1 >= 0) && (Y1 < YRES)
327 ; (Y2 >= 0) && (Y2 < YRES)
328 ; Must set an error code: NO
330 bit $C082 ; Switch in ROM
337 jsr HLINE ; Preserves X
341 bit $C080 ; Switch in LC bank 2 for R/O
344 ; ------------------------------------------------------------------------
346 .include "../tgi/tgidrv_line.inc"