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-mode.inc"
12 .include "tgi-error.inc"
15 ; ------------------------------------------------------------------------
32 ; ------------------------------------------------------------------------
34 ; Variables mapped to the zero page segment variables. Some of these are
35 ; used for passing parameters to the driver.
47 ; Line routine stuff (must be on zpage)
51 ERR := regsave ; (2) LINE
52 NX := regsave+2 ; (2) LINE
54 ; ------------------------------------------------------------------------
58 ; Header. Includes jump table and constants.
60 ; First part of the header is a structure that has a magic and defines the
61 ; capabilities of the driver
63 .byte $74, $67, $69 ; "tgi"
64 .byte TGI_API_VERSION ; TGI API version number
65 xres: .word 40 ; X resolution
66 yres: .word 48 ; Y resolution
67 .byte 16 ; Number of drawing colors
68 .byte 1 ; Number of screens available
69 .byte 8 ; System font X size
70 .byte 8 ; System font Y size
71 .word $100 ; Aspect ratio
73 ; Next comes the jump table. With the exception of IRQ, all entries must be
74 ; valid and may point to an RTS for test versions (function not implemented).
95 .addr 0 ; IRQ entry is unused
97 ; ------------------------------------------------------------------------
101 ; Absolute variables used in the code
103 ERROR: .res 1 ; Error code
105 ; Line routine stuff (combined with circle routine stuff to save space)
117 ; ------------------------------------------------------------------------
121 ; Constants and tables
123 DEFPALETTE: .byte $00, $01, $02, $03, $04, $05, $06, $07
124 .byte $08, $09, $0A, $0B, $0C, $0D, $0E, $0F
126 ; ------------------------------------------------------------------------
130 ; INIT: Changes an already installed device from text mode to graphics mode.
131 ; Note that INIT/DONE may be called multiple times while the driver
132 ; is loaded, while INSTALL is only called once, so any code that is needed
133 ; to initializes variables and so on must go here. Setting palette and
134 ; clearing the screen is not needed because this is called by the graphics
136 ; The graphics kernel will never call INIT when a graphics mode is already
137 ; active, so there is no need to protect against that.
138 ; Must set an error code: YES
140 ; Switch into graphics mode
141 bit $C082 ; Switch in ROM
144 bit $C080 ; Switch in LC bank 2 for R/O
146 ; Done, reset the error code
152 ; INSTALL routine. Is called after the driver is loaded into memory. May
153 ; initialize anything that has to be done just once. Is probably empty
155 ; Must set an error code: NO
159 ; UNINSTALL routine. Is called before the driver is removed from memory. May
160 ; clean up anything done by INSTALL but is probably empty most of the time.
161 ; Must set an error code: NO
165 ; SETVIEWPAGE: Set the visible page. Called with the new page in A (0..n).
166 ; The page number is already checked to be valid by the graphics kernel.
167 ; Must set an error code: NO (will only be called if page ok)
171 ; SETDRAWPAGE: Set the drawable page. Called with the new page in A (0..n).
172 ; The page number is already checked to be valid by the graphics kernel.
173 ; Must set an error code: NO (will only be called if page ok)
177 ; TEXTSTYLE: Set the style used when calling OUTTEXT. Text scaling in X and Y
178 ; direction is passend in X/Y, the text direction is passed in A.
179 ; Must set an error code: NO
183 ; OUTTEXT: Output text at X/Y = ptr1/ptr2 using the current color and the
184 ; current text style. The text to output is given as a zero terminated
185 ; string with address in ptr3.
186 ; Must set an error code: NO
190 ; DONE: Will be called to switch the graphics device back into text mode.
191 ; The graphics kernel will never call DONE when no graphics mode is active,
192 ; so there is no need to protect against that.
193 ; Must set an error code: NO
195 bit $C082 ; Switch in ROM
198 bit $C080 ; Switch in LC bank 2 for R/O
201 ; GETERROR: Return the error code in A and clear it.
208 ; CLEAR: Clears the screen.
209 ; Must set an error code: NO
211 bit $C082 ; Switch in ROM
213 bit $C080 ; Switch in LC bank 2 for R/O
216 ; SETCOLOR: Set the drawing color (in A). The new color is already checked
217 ; to be in a valid range (0..maxcolor-1).
218 ; Must set an error code: NO (will only be called if color ok)
220 bit $C082 ; Switch in ROM
222 bit $C080 ; Switch in LC bank 2 for R/O
225 ; CONTROL: Platform/driver specific entry point.
226 ; Must set an error code: YES
230 ; SETPALETTE: Set the palette (not available with all drivers/hardware).
231 ; A pointer to the palette is passed in ptr1. Must set an error if palettes
233 ; Must set an error code: YES
235 lda #TGI_ERR_INV_FUNC
239 ; GETPALETTE: Return the current palette in A/X. Even drivers that cannot
240 ; set the palette should return the default palette here, so there's no
241 ; way for this function to fail.
242 ; Must set an error code: NO
246 ; GETDEFPALETTE: Return the default palette for the driver in A/X. All
247 ; drivers should return something reasonable here, even drivers that don't
248 ; support palettes, otherwise the caller has no way to determine the colors
249 ; of the (not changeable) palette.
250 ; Must set an error code: NO (all drivers must have a default palette)
256 ; SETPIXEL: Draw one pixel at X1/Y1 = ptr1/ptr2 with the current drawing
257 ; color. The coordinates passed to this function are never outside the
258 ; visible screen area, so there is no need for clipping inside this function.
259 ; Must set an error code: NO
261 bit $C082 ; Switch in ROM
265 bit $C080 ; Switch in LC bank 2 for R/O
268 ; GETPIXEL: Read the color value of a pixel and return it in A/X. The
269 ; coordinates passed to this function are never outside the visible screen
270 ; area, so there is no need for clipping inside this function.
272 bit $C082 ; Switch in ROM
277 bit $C080 ; Switch in LC bank 2 for R/O
280 ; LINE: Draw a line from X1/Y1 to X2/Y2, where X1/Y1 = ptr1/ptr2 and
281 ; X2/Y2 = ptr3/ptr4 using the current drawing color.
282 ; Must set an error code: NO
386 ; for (count = nx; count > 0; --count) {
391 for: lda COUNT ; count > 0
442 ; if (abs (pb) < abs (ub)) {
460 ; else { x1 = x1 + ax
500 ; BAR: Draw a filled rectangle with the corners X1/Y1, X2/Y2, where
501 ; X1/Y1 = ptr1/ptr2 and X2/Y2 = ptr3/ptr4 using the current drawing color.
502 ; Contrary to most other functions, the graphics kernel will sort and clip
503 ; the coordinates before calling the driver, so on entry the following
504 ; conditions are valid:
507 ; (X1 >= 0) && (X1 < XRES)
508 ; (X2 >= 0) && (X2 < XRES)
509 ; (Y1 >= 0) && (Y1 < YRES)
510 ; (Y2 >= 0) && (Y2 < YRES)
511 ; Must set an error code: NO
513 bit $C082 ; Switch in ROM
524 bit $C080 ; Switch in LC bank 2 for R/O
527 ; Copies of some runtime routines
547 ; Compare A/Y to zp,X
548 sta TEMP ; TEMP/TEMP2 - arg2
556 tya ; X/A - arg1 (a = high)