--- /dev/null
+;
+; Graphics driver for the 240x200x2 mode on the Atmos
+;
+; Stefan Haubenthal <polluks@sdf.lonestar.org>
+;
+
+ .include "zeropage.inc"
+
+ .include "tgi-kernel.inc"
+ .include "tgi-mode.inc"
+ .include "tgi-error.inc"
+ .include "atmos.inc"
+
+ .macpack generic
+
+; ------------------------------------------------------------------------
+; Header. Includes jump table and constants.
+
+.segment "JUMPTABLE"
+
+; First part of the header is a structure that has a magic and defines the
+; capabilities of the driver
+
+ .byte $74, $67, $69 ; "tgi"
+ .byte TGI_API_VERSION ; TGI API version number
+ .word 240 ; X resolution
+ .word 200 ; Y resolution
+ .byte 2 ; Number of drawing colors
+ .byte 1 ; Number of screens available
+xsize: .byte 6 ; System font X size
+ .byte 8 ; System font Y size
+ .res 4, $00 ; Reserved for future extensions
+
+; Next comes the jump table. Currently all entries must be valid and may point
+; to an RTS for test versions (function not implemented).
+
+ .word INSTALL
+ .word UNINSTALL
+ .word INIT
+ .word DONE
+ .word GETERROR
+ .word CONTROL
+ .word CLEAR
+ .word SETVIEWPAGE
+ .word SETDRAWPAGE
+ .word SETCOLOR
+ .word SETPALETTE
+ .word GETPALETTE
+ .word GETDEFPALETTE
+ .word SETPIXEL
+ .word GETPIXEL
+ .word LINE
+ .word BAR
+ .word _CIRCLE
+ .word TEXTSTYLE
+ .word OUTTEXT
+
+; ------------------------------------------------------------------------
+; Data.
+
+; Variables mapped to the zero page segment variables. Some of these are
+; used for passing parameters to the driver.
+
+X1 = ptr1
+Y1 = ptr2
+X2 = ptr3
+Y2 = ptr4
+RADIUS = tmp1
+
+; Absolute variables used in the code
+
+.bss
+
+ERROR: .res 1 ; Error code
+MODE: .res 1 ; Graphics mode
+
+; Constants and tables
+PARAM1 = $2E1
+PARAM2 = $2E3
+PARAM3 = $2E5
+TEXT = $EC21
+HIRES = $EC33
+CURSET = $F0C8
+CURMOV = $F0FD
+DRAW = $F110
+CHAR = $F12D
+POINT = $F1C8
+PAPER = $F204
+INK = $F210
+CIRCLE = $F37F
+
+.rodata
+
+DEFPALETTE: .byte $00, $07
+
+.code
+
+; ------------------------------------------------------------------------
+; INSTALL routine. Is called after the driver is loaded into memory. May
+; initialize anything that has to be done just once. Is probably empty
+; most of the time.
+;
+; Must set an error code: NO
+;
+
+INSTALL:
+
+; ------------------------------------------------------------------------
+; UNINSTALL routine. Is called before the driver is removed from memory. May
+; clean up anything done by INSTALL but is probably empty most of the time.
+;
+; Must set an error code: NO
+;
+
+UNINSTALL:
+ rts
+
+; ------------------------------------------------------------------------
+; INIT: Changes an already installed device from text mode to graphics
+; mode.
+; Note that INIT/DONE may be called multiple times while the driver
+; is loaded, while INSTALL is only called once, so any code that is needed
+; to initializes variables and so on must go here. Setting palette and
+; clearing the screen is not needed because this is called by the graphics
+; kernel later.
+; The graphics kernel will never call INIT when a graphics mode is already
+; active, so there is no need to protect against that.
+;
+; Must set an error code: YES
+;
+
+INIT:
+
+; Switch into graphics mode
+
+ jsr HIRES
+
+; Done, reset the error code
+
+ lda #TGI_ERR_OK
+ sta ERROR
+ rts
+
+; ------------------------------------------------------------------------
+; DONE: Will be called to switch the graphics device back into text mode.
+; The graphics kernel will never call DONE when no graphics mode is active,
+; so there is no need to protect against that.
+;
+; Must set an error code: NO
+;
+
+DONE = TEXT
+
+; ------------------------------------------------------------------------
+; GETERROR: Return the error code in A and clear it.
+
+GETERROR:
+ ldx #TGI_ERR_OK
+ lda ERROR
+ stx ERROR
+ rts
+
+; ------------------------------------------------------------------------
+; CONTROL: Platform/driver specific entry point.
+;
+; Must set an error code: YES
+;
+
+CONTROL:
+ sta $213
+ lda #TGI_ERR_OK
+ sta ERROR
+ rts
+
+; ------------------------------------------------------------------------
+; CLEAR: Clears the screen.
+;
+; Must set an error code: NO
+;
+
+CLEAR = HIRES
+
+; ------------------------------------------------------------------------
+; SETVIEWPAGE: Set the visible page. Called with the new page in A (0..n).
+; The page number is already checked to be valid by the graphics kernel.
+;
+; Must set an error code: NO (will only be called if page ok)
+;
+
+SETVIEWPAGE:
+
+; ------------------------------------------------------------------------
+; SETDRAWPAGE: Set the drawable page. Called with the new page in A (0..n).
+; The page number is already checked to be valid by the graphics kernel.
+;
+; Must set an error code: NO (will only be called if page ok)
+;
+
+SETDRAWPAGE:
+ rts
+
+; ------------------------------------------------------------------------
+; SETCOLOR: Set the drawing color (in A). The new color is already checked
+; to be in a valid range (0..maxcolor-1).
+;
+; Must set an error code: NO (will only be called if color ok)
+;
+
+SETCOLOR:
+ sta MODE
+ rts
+
+; ------------------------------------------------------------------------
+; SETPALETTE: Set the palette (not available with all drivers/hardware).
+; A pointer to the palette is passed in ptr1. Must set an error if palettes
+; are not supported
+;
+; Must set an error code: YES
+;
+
+SETPALETTE:
+ ldy #0
+ lda (ptr1),y
+ sta PARAM1
+ jsr PAPER
+ ldy #1
+ lda (ptr1),y
+ sta PARAM1
+ jsr INK
+ lda #TGI_ERR_OK
+ sta ERROR
+ rts
+
+; ------------------------------------------------------------------------
+; GETPALETTE: Return the current palette in A/X. Even drivers that cannot
+; set the palette should return the default palette here, so there's no
+; way for this function to fail.
+;
+; Must set an error code: NO
+;
+
+GETPALETTE:
+
+; ------------------------------------------------------------------------
+; GETDEFPALETTE: Return the default palette for the driver in A/X. All
+; drivers should return something reasonable here, even drivers that don't
+; support palettes, otherwise the caller has no way to determine the colors
+; of the (not changeable) palette.
+;
+; Must set an error code: NO (all drivers must have a default palette)
+;
+
+GETDEFPALETTE:
+ lda #<DEFPALETTE
+ ldx #>DEFPALETTE
+ rts
+
+; ------------------------------------------------------------------------
+; SETPIXEL: Draw one pixel at X1/Y1 = ptr1/ptr2 with the current drawing
+; color. The coordinates passed to this function are never outside the
+; visible screen area, so there is no need for clipping inside this function.
+;
+; Must set an error code: NO
+;
+
+SETPIXEL:
+ lda MODE
+mymode: sta PARAM3
+ lda X1
+ sta PARAM1
+ lda Y1
+ sta PARAM2
+ lda #0
+ sta PARAM1+1
+ sta PARAM2+1
+ jmp CURSET
+
+; ------------------------------------------------------------------------
+; GETPIXEL: Read the color value of a pixel and return it in A/X. The
+; coordinates passed to this function are never outside the visible screen
+; area, so there is no need for clipping inside this function.
+
+GETPIXEL:
+ lda X1
+ sta PARAM1
+ lda Y1
+ sta PARAM2
+ lda #0
+ sta PARAM1+1
+ sta PARAM2+1
+ jsr POINT
+ lda PARAM1
+ and #%00000001
+ ldx #0
+ rts
+
+; ------------------------------------------------------------------------
+; LINE: Draw a line from X1/Y1 to X2/Y2, where X1/Y1 = ptr1/ptr2 and
+; X2/Y2 = ptr3/ptr4 using the current drawing color.
+;
+; Must set an error code: NO
+;
+
+LINE:
+ jsr SETPIXEL
+ lda X2
+ sub X1
+ sta PARAM1
+ lda X2+1
+ sbc X1+1
+ sta PARAM1+1
+ lda Y2
+ sub Y1
+ sta PARAM2
+ lda Y2+1
+ sbc Y1+1
+ sta PARAM2+1
+ lda MODE
+ sta PARAM3
+ jmp DRAW
+
+; ------------------------------------------------------------------------
+; BAR: Draw a filled rectangle with the corners X1/Y1, X2/Y2, where
+; X1/Y1 = ptr1/ptr2 and X2/Y2 = ptr3/ptr4 using the current drawing color.
+; Contrary to most other functions, the graphics kernel will sort and clip
+; the coordinates before calling the driver, so on entry the following
+; conditions are valid:
+; X1 <= X2
+; Y1 <= Y2
+; (X1 >= 0) && (X1 < XRES)
+; (X2 >= 0) && (X2 < XRES)
+; (Y1 >= 0) && (Y1 < YRES)
+; (Y2 >= 0) && (Y2 < YRES)
+;
+; Must set an error code: NO
+;
+
+BAR:
+ inc Y2
+@L1: lda Y2
+ pha
+ lda Y1
+ sta Y2
+ jsr LINE
+ pla
+ sta Y2
+ inc Y1
+ cmp Y1
+ bne @L1
+ rts
+
+; ------------------------------------------------------------------------
+; CIRCLE: Draw a circle around the center X1/Y1 (= ptr1/ptr2) with the
+; radius in tmp1 and the current drawing color.
+;
+; Must set an error code: NO
+;
+
+_CIRCLE:
+ lda #3
+ jsr mymode
+ lda RADIUS
+ sta PARAM1
+ lda MODE
+ sta PARAM2
+ jmp CIRCLE
+
+; ------------------------------------------------------------------------
+; TEXTSTYLE: Set the style used when calling OUTTEXT. Text scaling in X and Y
+; direction is passend in X/Y, the text direction is passed in A.
+;
+; Must set an error code: NO
+;
+
+TEXTSTYLE:
+ rts
+
+
+; ------------------------------------------------------------------------
+; OUTTEXT: Output text at X/Y = ptr1/ptr2 using the current color and the
+; current text style. The text to output is given as a zero terminated
+; string with address in ptr3.
+;
+; Must set an error code: NO
+;
+
+OUTTEXT:
+ lda X1
+ sta PARAM1
+ lda Y1
+ sta PARAM2
+ lda #3
+ sta PARAM3
+ jsr CURSET
+
+ ldy #0
+@next: lda (ptr3),y
+ beq @end
+ sta PARAM1
+ lda #0
+ sta PARAM2
+ lda MODE
+ sta PARAM3
+ tya
+ pha
+ jsr CHAR
+ lda xsize
+ sta PARAM1
+ lda #0
+ sta PARAM2
+ lda #3
+ sta PARAM3
+ jsr CURMOV
+ pla
+ tay
+ iny
+ bne @next
+@end: rts
projects / cc65 / commitdiff