; ; Graphics driver for the lores 64x56x2 mode on the NES ; ; Stefan Haubenthal, 2009-03-10 ; Based on Maciej Witkowiak's line routine. ; .include "zeropage.inc" .include "tgi-kernel.inc" .include "tgi-error.inc" .include "nes.inc" .include "get_tv.inc" .import _clrscr, setcursor, putchar .import paldata .macpack generic ; ------------------------------------------------------------------------ ; Header. Includes jump table and constants. .segment "HEADER" ; 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 .addr $0000 ; Library reference xres: .word charsperline*2 ; Max X resolution yres: .word 56 ; Max Y resolution .byte 2 ; Number of drawing colors .byte 1 ; Number of screens available .byte 2 ; System font X size .byte 2 ; System font Y size .word $0100 ; Aspect ratio .byte 0 ; TGI driver flags ; Next comes the jump table. Currently all entries must be valid and may point ; to an RTS for test versions (function not implemented). .addr INSTALL .addr UNINSTALL .addr INIT .addr DONE .addr GETERROR .addr CONTROL .addr CLEAR .addr SETVIEWPAGE .addr SETDRAWPAGE .addr SETCOLOR .addr SETPALETTE .addr GETPALETTE .addr GETDEFPALETTE .addr SETPIXEL .addr GETPIXEL .addr LINE .addr BAR .addr TEXTSTYLE .addr OUTTEXT .addr 0 ; IRQ entry is unused ; ------------------------------------------------------------------------ ; 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 ADDR = tmp1 TEMP = tmp3 TEMP2 = tmp4 TEMP3 = sreg TEMP4 = sreg+1 ; Line routine stuff (must be on zpage) PB = ptr3 ; (2) LINE UB = ptr4 ; (2) LINE ERR = regsave ; (2) LINE NX = regsave+2 ; (2) LINE ; Absolute variables used in the code .bss MEM: .res charsperline*2*56/4 MEMEND: ERROR: .res 1 ; Error code COLOR: .res 1 ; Current color PALETTE: .res 2 ; The current palette ; Line routine stuff OGora: COUNT: .res 2 OUkos: NY: .res 2 Y3: DX: .res 1 DY: .res 1 AY: .res 1 ; Constants and tables .rodata DEFPALETTE: .byte $0, $1 OFFSET: .byte 8, 4, 2, 1 ; 00 00 00 00 01 01 01 01 ; 00 01 10 11 00 01 10 11 CODE: .byte 32, 29, 26, 25, 28, 24+128, 31+128, 30+128 ; 10 10 10 10 11 11 11 11 ; 00 01 10 11 00 01 10 11 .byte 30, 31, 24, 28+128, 25+128, 26+128, 29+128, 32+128 .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: jsr _get_tv cmp #TV::NTSC beq ntsc ; TODO ROM! inc yres inc yres ntsc:; 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: lda ERROR ldx #TGI_ERR_OK 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 ; CLEAR: ldx #MEM stx TEMP+1 lda #0 tay @L1: sta (TEMP),y iny bne @L1 inc TEMP+1 inx cpx #>MEMEND bne @L1 jmp _clrscr ; ------------------------------------------------------------------------ ; 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 COLOR ; 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: ; ------------------------------------------------------------------------ ; 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 ; ------------------------------------------------------------------------ ; 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: ; Wait for v-blank @wait: lda PPU_STATUS bpl @wait lda #$3F sta PPU_VRAM_ADDR2 lda #$00 sta PPU_VRAM_ADDR2 ldy #0 lda (ptr1),y sta PALETTE tax lda paldata,x ; sta PPU_VRAM_IO iny lda (ptr1),y sta PALETTE+1 tax lda paldata,x sta PPU_VRAM_IO 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 #PALETTE 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 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: ldx Y1 ; y+2= 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 X1 pha @L2: jsr SETPIXEL inc X1 lda X2 cmp X1 bne @L2 pla sta X1 inc Y1 lda Y2 cmp Y1 bne @L1 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: 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 ptr1 lsr tay lda ptr2 lsr tax clc jsr setcursor ldy #0 @L1: lda (ptr3),y jsr putchar iny cmp #$0 bne @L1 rts ; ------------------------------------------------------------------------ ; Calculate all variables to plot the pixel at X1/Y1. If the point is out ; of range, a carry is returned and INRANGE is set to a value !0 zero. If ; the coordinates are valid, INRANGE is zero and the carry clear. CALC: lda xres sta TEMP lda #0 sta TEMP+1 ldy Y1 @L1: lda TEMP add xres lsr sta TEMP lda TEMP+1 adc #0 lsr sta TEMP+1 dey bne @L1 lda TEMP add X1 lsr sta TEMP lda TEMP+1 adc #0 lsr sta TEMP+1 lda TEMP add #MEM sta TEMP+1 lda X1 and #%00000001 sta TEMP3 lda Y1 asl and #%00000010 ora TEMP3 tax lda OFFSET,x rts ; ------------------------------------------------------------------------ .include "../../tgi/tgidrv_line.inc"