--- /dev/null
+;
+; Graphics driver for the 160x102x16 mode on the Lynx.
+;
+; Based on Stephen L. Judds GRLIB code
+;
+
+ .include "zeropage.inc"
+
+ .include "tgi-kernel.inc"
+ .include "tgi-mode.inc"
+ .include "tgi-error.inc"
+
+ .include "lynx.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 160 ; X resolution
+ .word 102 ; Y resolution
+ .byte 16 ; Number of drawing colors
+ .byte 1 ; Number of screens available
+ .byte 8 ; 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). A future version may
+; allow for emulation: In this case the vector will be zero. Emulation means
+; that the graphics kernel will emulate the function by using lower level
+; primitives - for example ploting a line by using calls to SETPIXEL.
+
+ .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
+
+ROW := tmp2 ; Bitmap row...
+COL := tmp3 ; ...and column, both set by PLOT
+TEMP := tmp4
+TEMP2 := sreg
+POINT := regsave
+INRANGE := regsave+2 ; PLOT variable, $00 = coordinates in range
+
+CHUNK := X2 ; Used in the line routine
+OLDCHUNK := X2+1 ; Dito
+
+; Absolute variables used in the code
+
+.bss
+
+ERROR: .res 1 ; Error code
+
+DRAWINDEX: .res 1 ; Pen to use for drawing
+VIEWPAGEL: .res 1
+VIEWPAGEH: .res 1
+
+; INIT/DONE
+OLDD018: .res 1 ; Old register value
+
+; Line routine stuff
+DX: .res 2
+DY: .res 2
+
+; Circle routine stuff, overlaid by BAR variables
+X1SAVE:
+CURX: .res 1
+CURY: .res 1
+Y1SAVE:
+BROW: .res 1 ; Bottom row
+TROW: .res 1 ; Top row
+X2SAVE:
+LCOL: .res 1 ; Left column
+RCOL: .res 1 ; Right column
+Y2SAVE:
+CHUNK1: .res 1
+OLDCH1: .res 1
+CHUNK2: .res 1
+OLDCH2: .res 1
+
+; Text output stuff
+TEXTMAGX: .res 1
+TEXTMAGY: .res 1
+TEXTDIR: .res 1
+
+; Constants and tables
+
+.rodata
+
+DEFPALETTE: .byte >$000
+ .byte >$007
+ .byte >$070
+ .byte >$700
+ .byte >$077
+ .byte >$770
+ .byte >$707
+ .byte >$777
+ .byte >$333
+ .byte >$00F
+ .byte >$0F0
+ .byte >$F00
+ .byte >$0FF
+ .byte >$FF0
+ .byte >$F0F
+ .byte >$FFF
+ .byte <$000
+ .byte <$007
+ .byte <$070
+ .byte <$700
+ .byte <$077
+ .byte <$770
+ .byte <$707
+ .byte <$777
+ .byte <$333
+ .byte <$00F
+ .byte <$0F0
+ .byte <$F00
+ .byte <$0FF
+ .byte <$FF0
+ .byte <$F0F
+ .byte <$FFF
+
+PALETTESIZE = * - DEFPALETTE
+
+BITTAB: .byte $80,$40,$20,$10,$08,$04,$02,$01
+BITCHUNK: .byte $FF,$7F,$3F,$1F,$0F,$07,$03,$01
+
+VBASE = $E000 ; Video memory base address
+CBASE = $D000 ; Color memory base address
+
+
+.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:
+ rts
+
+
+; ------------------------------------------------------------------------
+; 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:
+; 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:
+ rts
+
+; ------------------------------------------------------------------------
+; 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:
+ lda #TGI_ERR_INV_FUNC
+ sta ERROR
+ rts
+
+; ------------------------------------------------------------------------
+; CLEAR: Clears the screen.
+;
+; Must set an error code: NO
+;
+
+.rodata
+pixel_bitmap:
+ .byte 3,%10000100,%00000000, $0 ; A pixel bitmap
+cls_sprite:
+ .byte %00000001 ; A pixel sprite
+ .byte %00010000
+ .byte %00100000
+ .addr 0,pixel_bitmap
+ .word 0
+ .word 0
+ .word $a000 ; 160
+ .word $6600 ; 102
+ .byte $00
+
+.code
+CLEAR: lda #<cls_sprite
+ ldx #>cls_sprite
+draw_sprite:
+ sta $fc10
+ stx $fc11
+ lda #1
+ sta $fc91
+ stz $fd90
+@L3: stz CPUSLEEP
+ lda $fc92
+ lsr
+ bcs @L3
+ stz $fd90
+ rts
+
+; ------------------------------------------------------------------------
+; SETVIEWPAGE: Set the visible page. Called with the new page in A (0..n).
+; The page number is already checked to be valid by the graphics kernel.
+;
+; Must set an error code: NO (will only be called if page ok)
+;
+
+SETVIEWPAGE:
+ beq @L1
+ lda #<$fe00-8160-8160
+ ldx #>$fe00-8160-8160
+ bra @L2
+@L1: lda #<$fe00-8160
+ ldx #>$fe00-8160
+@L2: sta DISPADRL ; $FD94
+ sta VIEWPAGEL
+ stx DISPADRH ; $FD95
+ sta VIEWPAGEH
+ rts
+
+; ------------------------------------------------------------------------
+; SETDRAWPAGE: Set the drawable page. Called with the new page in A (0..n).
+; The page number is already checked to be valid by the graphics kernel.
+;
+; Must set an error code: NO (will only be called if page ok)
+;
+
+SETDRAWPAGE:
+ beq @L1
+ lda #<$fe00-8160-8160
+ ldx #>$fe00-8160-8160
+ bra @L2
+@L1: lda #<$fe00-8160
+ ldx #>$fe00-8160
+@L2: sta VIDBASL ; $FD94
+ stx VIDBASH ; $FD95
+ 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 DRAWINDEX
+ 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 #31
+@L1: lda (ptr1),y
+ sta GCOLMAP,y ; $FDA0
+ dey
+ bpl @L1
+
+; Done, reset the error code
+
+ 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:
+ lda #<GCOLMAP ; $FDA0
+ ldx #>GCOLMAP
+ rts
+
+; ------------------------------------------------------------------------
+; 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
+;
+
+.data
+pixel_sprite:
+ .byte %00000001 ; A pixel sprite
+ .byte %00010000
+ .byte %00100000
+ .addr 0,pixel_bitmap
+pix_x: .word 0
+pix_y: .word 0
+ .word $0100
+ .word $0100
+pix_c: .byte $00
+
+.code
+SETPIXEL:
+ lda X1
+ sta pix_x
+ lda Y1
+ sta pix_y
+ lda DRAWINDEX
+ sta pix_c
+ lda #<pixel_sprite
+ ldx #>pixel_sprite
+ jmp draw_sprite
+
+; ------------------------------------------------------------------------
+; GETPIXEL: Read the color value of a pixel and return it in A/X. The
+; coordinates passed to this function are never outside the visible screen
+; area, so there is no need for clipping inside this function.
+
+
+GETPIXEL:
+ lda Y1
+ sta MATHD ; Hardware multiply
+ stz MATHC
+ lda #80
+ sta MATHB
+ stz MATHA
+ lda X1
+ lsr A
+ php
+ tay
+
+ clc
+ lda VIEWPAGEL
+ adc MATHH
+ sta ptr1
+ lda VIEWPAGEH
+ adc MATHG
+ sta ptr1+1
+
+ ldx #0
+ lda (ptr1),y
+ plp
+ bcc @L1
+ and #$f
+ rts
+
+@L1: lsr A
+ lsr A
+ lsr A
+ lsr A
+ 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.
+;
+; To deal with off-screen coordinates, the current row
+; and column (40x25) is kept track of. These are set
+; negative when the point is off the screen, and made
+; positive when the point is within the visible screen.
+;
+; X1,X2 etc. are set up above (x2=LINNUM in particular)
+; Format is LINE x2,y2,x1,y1
+;
+; Must set an error code: NO
+;
+
+LINE:
+ rts
+
+; ------------------------------------------------------------------------
+; 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
+;
+
+.data
+bar_sprite:
+ .byte %00000001 ; A pixel sprite
+ .byte %00010000
+ .byte %00100000
+ .addr 0,pixel_bitmap
+bar_x: .word 0
+bar_y: .word 0
+bar_sx: .word $0100
+bar_sy: .word $0100
+bar_c: .byte $00
+
+.code
+BAR: lda X1
+ sta bar_x
+ lda Y1
+ sta bar_y
+ lda X2
+ sec
+ sbc X1
+ sta bar_sx+1
+ lda Y2
+ sec
+ sbc Y1
+ sta bar_sy+1
+ lda DRAWINDEX
+ sta bar_c
+ lda #<bar_sprite
+ ldx #>bar_sprite
+ jmp draw_sprite
+
+; ------------------------------------------------------------------------
+; 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:
+ rts
+
+; ------------------------------------------------------------------------
+; 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:
+ stx TEXTMAGX
+ sty TEXTMAGY
+ sta TEXTDIR
+ 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:
+ rts
+
projects / cc65 / commitdiff