139 lines
2.1 KiB
ArmAsm
139 lines
2.1 KiB
ArmAsm
; Double hi-res Rasterbars
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GBASL = $26
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GBASH = $27
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HGRPAGE = $E6
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BASE = $FC
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LINE = $FD
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YPOS = $FE
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COLOR = $FF
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HGR = $F3E2
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HGR2 = $F3D8
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HPOSN = $F411
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raster:
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;=========================
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; configure double hires
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;=========================
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jsr HGR
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jsr HGR2
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sta $C05E ; set double hires
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sta $C00D ; 80 column
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sta $C001 ; 80 store
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lsr HGRPAGE ; set to $20 (HGR2 set this to $40)
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; ldy #100
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big_loop:
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lda #0 ; 2 ; blueline
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jsr one_line ; 3
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lda #4 ; 2 ; redline
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jsr one_line ; 3
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tya ; YPOS
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bmi go_neg ; if >128, flip to go up
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cmp #64 ; if < 64, flip to go down
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bcs smc ; otherwise, nothing
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go_pos:
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ldx #$c8
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.byte $2C ; bit trick
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go_neg:
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ldx #$88
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stx smc
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smc: ; move the bar
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iny ; c8=iny, 88=dey
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bne big_loop ; bra
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one_line:
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sta BASE ; 2
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tya ; 1
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eor #$10 ; 2
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tay ; 1
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; fallthrough
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;=======================================
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draw_raster:
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lda #7 ; want 8 lines
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sta LINE
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color_loop: ; get right color
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lda LINE ;(2)
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cmp #$4 ;(2)
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bcc none ;(2)
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eor #$3 ; 2 00 01 10 11 00 01 10 11
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none: ; 11 10 01 00
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and #$3 ;(2)
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clc
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color_smc:
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adc BASE
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tax
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lda colors,X
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sta COLOR
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tya
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pha ; save YPOS
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; sec ; c always 0
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sbc LINE
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;=============================
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; draw line of color in COLOR
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;=============================
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draw_line_color:
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ldx #0
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ldy #0
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jsr HPOSN ; put into GBASL addr of coord (Y,X),A
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ldy #39
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loop_it:
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; set page2
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sta $C055 ; 3
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jsr next_pixel ; 3
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; set page1
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sta $C054 ; 3
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jsr next_pixel ; 3
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dey ; 1
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bpl loop_it ; 2
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pla
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tay
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;====================================
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dec LINE
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bpl color_loop
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rts
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;==============================
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;==============================
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next_pixel:
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lda COLOR ; 2
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sta (GBASL),Y ; 2
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cmp #$80 ; 2
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rol COLOR ; 2
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rts ; 1
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colors:
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.byte $00,$11,$22,$33 ; red
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.byte $00,$DD,$EE,$FF ; blue/white
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; .byte $00,$11,$22,$33,$33,$22,$11,$00 ; red
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; .byte $00,$DD,$EE,$FF,$FF,$EE,$DD,$00 ; black aqua lblue white
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; .byte $00,$AA,$BB,$CC,$CC,$BB,$AA,$00 ; grey yellow mblue
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; .byte $00,$77,$88,$99,$99,$88,$77,$00 ; ugly green
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; .byte $00,$44,$55,$66,$66,$55,$44,$00 ; purple
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