A2osX/DRV/DHGR.DRV.S.PIX.txt

PR#3
PREFIX /A2OSX.BUILD
LOMEM $A00
INC 1
AUTO 6
				.LIST OFF	
*--------------------------------------
* SETPIXEL
*	1 : OP (XOR,SET,ORA)
*   2 : Mode
*	3 : Color
*   4 : SrcX1
*   6 : SrcY1
*--------------------------------------
SETPIXEL		lda CB.Cache+S.CB.MODE
				bit #S.CB.MODE.C16
				bne SETPIXEL.C16

SETPIXEL.MONO	>LDYA CB.Cache+S.CB.X1

				jsr DIVMOD7YA
				tay
				lda COL.OFS,y
				phy
				
				ldy CB.Cache+S.CB.Y1
				clc
				adc BASEL,y
				sta ZPBasePtr
				lda BASEH,y
				sta ZPBasePtr+1
				
				ply
				lda COL.BANK,y
				tay
				sta $C000,y				Select proper BANK
				
				lda CB.Cache+S.CB.OP
*				cmp #S.CB.OP.XOR
				beq SETPIXEL.MONO.XOR
				
				lda CB.Cache+S.CB.COLOR
				bne SETPIXEL.MONO.WHITE
				
SETPIXEL.MONO.BLACK				
				lda (ZPBasePtr)
				and Mono.NMasks,x
				sta (ZPBasePtr)

				rts

SETPIXEL.MONO.WHITE
				lda (ZPBasePtr)
				and #$7f				Clear Color Bit
				ora Mono.Masks,x
				sta (ZPBasePtr)
				
				rts
				
SETPIXEL.MONO.XOR				
				lda (ZPBasePtr)
				and #$7f				Clear Color Bit
				eor Mono.Masks,x
				sta (ZPBasePtr)
				
				rts
	
SETPIXEL.C16	lda CB.Cache+S.CB.X1
				lsr CB.Cache+S.CB.X1+1			divide by 4
				ror
				lsr CB.Cache+S.CB.X1+1
				ror
				tay						Y=X/4 (range 0->139)
				lda DIV7.0,y			A=X/4/7 (range 0->19)
				
				asl						times 2  (range 0->38)
				
				ldx CB.Cache+S.CB.Y1
*				clc				
				adc BASEL,x				setup line Base Ptr (cc by asl)
				sta ZPBasePtr			ZPBasePtr now point to first of...
				lda BASEH,x
				sta ZPBasePtr+1			...the 4 columns

				lda MOD7.0,y			get MOD
				
				asl						times 4 to compute index in MASK tables
				asl
				tax						set in X for Masks,NMasks
				
				lda CB.Cache+S.CB.COLOR
				
				asl						times 4 to compute index in PIXELS table
				asl
				tay

				lda Color.Masks,x		bits in 1st byte to light?
				beq .10
				and Color.Pixels,y		apply color
				sta GBYTE
				
				sta SETPAGE2
				
				lda (ZPBasePtr)
				and Color.NMasks,x		reset existing pixel, 
				ora GBYTE
				sta (ZPBasePtr)

.10				inx
				iny
				
				lda Color.Masks,x
				beq .11
				and Color.Pixels,y		apply color
				sta GBYTE
				
				sta CLRPAGE2

				lda (ZPBasePtr)
				and Color.NMasks,x		reset existing pixel, 
				ora GBYTE
				sta (ZPBasePtr)
				
.11				inc ZPBasePtr
				inx
				iny
				
				lda Color.Masks,x
				beq .12
				and Color.Pixels,y		apply color
				sta GBYTE
				
				sta SETPAGE2
				
				lda (ZPBasePtr)
				and Color.NMasks,x		reset existing pixel, 
				ora GBYTE
				sta (ZPBasePtr)
				
.12				inx
				iny
				
				lda Color.Masks,x
				beq .13
				and Color.Pixels,y		apply color
				sta GBYTE
				
				sta CLRPAGE2
				
				lda (ZPBasePtr)
				and Color.NMasks,x		reset existing pixel, 
				ora GBYTE
				sta (ZPBasePtr)
				
.13				rts
*--------------------------------------
* GETPIXEL
*--------------------------------------
GETPIXEL		rts
*--------------------------------------
MAN
SAVE /A2OSX.SRC/DRV/DHGR.DRV.S.PIX
LOAD /A2OSX.SRC/DRV/DHGR.DRV.S
ASM