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

PR#3
PREFIX /A2OSX.BUILD
LOMEM $A00
INC 1
AUTO 6
				.LIST OFF	
*--------------------------------------
* SETPIXEL
*  In : YA = Ptr to CtrlBlk :
*	1 : OP (XOR only)
*   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	ldx CB.Cache+S.CB.X1+1	Get X Hi byte....

				lda DIV7.lo,x
				sta .1+1
				lda DIV7.hi,x
				sta .1+2
				
				lda MOD7.lo,x
				sta .2+1
				lda MOD7.hi,x
				sta .2+2
				
				lda DIV7.BASE,x
				ldx CB.Cache+S.CB.X1
				
				clc
.1				adc $ffff,x				DIV7 : x = X.LO, a = X DIV 7
				
				pha						save X DIV 7
				lsr
				ldy CB.Cache+S.CB.Y1
				clc
				adc BASEL,y				setup line Base Ptr (A=Col)
				sta ZPBase
				lda BASEH,y
				sta ZPBase+1
				ply
				lda COL.BANK,y
				tay
				sta $c000,y

.2				ldy $ffff,x				MOD7 : x = X.LO, y = X MOD 7		

				lda CB.Cache+S.CB.OP
				beq .5
				
				lda (ZPBase)			XOR
				eor Mono.Masks,y		y = mod 7
				sta (ZPBase)
				
				rts
				
.5				lda (ZPBase)
				ldx CB.Cache+S.CB.COLOR	get color
				bne .6
				
				and Mono.NMasks,y		includes And $7F for mono 
				sta (ZPBase)
				rts
				
.6				and #$7F				switch back this byte to mono
				ora Mono.Masks,y
				sta (ZPBase)
				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
				adc BASEL,x				setup line Base Ptr (cc by asl)
				sta ZPBase				ZPBase now point to first of...
				lda BASEH,x
				sta ZPBase+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 (ZPBase)
				and Color.NMasks,x		reset existing pixel, 
				ora GBYTE
				sta (ZPBase)

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

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