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https://github.com/a2-4am/4cade.git
synced 2025-02-17 07:31:19 +00:00
some minor tweaks and comments
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parent
3dfc71a25a
commit
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@ -5,22 +5,22 @@
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!to "build/FX/BIT.FIZZLE",plain
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*=$6000
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copymasks = $6100 ; [256 bytes, page-aligned]
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addrs = $6200 ; [256 bytes, page-aligned]
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addrs = $6100 ; [256 bytes, page-aligned]
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copymasks = $6200 ; [256 bytes, page-aligned]
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jsr swapzp ; copy LFSR code to zero page
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inx
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lda #1 ; create copymask lookup table
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inx ; X=0
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lda #%00000001 ; create copymask lookup table
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-- ldy #$20
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ora #$80
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ora #%10000000
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- sta copymasks, x
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inx
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dey
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bne -
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asl
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bne --
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; X=0
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clc
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-- ldy #$20 ; create address lookup table
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tya
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@ -31,7 +31,7 @@ addrs = $6200 ; [256 bytes, page-aligned]
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bne -
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txa
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bne --
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; X,Y=0
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jsr $0 ; call LFSR code on zero page
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lda $4000 ; last lousy byte (because LFSR never hits 0)
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@ -44,7 +44,7 @@ swapzp ldx #(end-start-1)
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sty $0, x
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dex
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bpl -
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rts
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rts ; X=#$FF
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start
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!pseudopc 0 {
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@ -10,7 +10,7 @@ copymasks = $6200 ; [128 bytes, should not cross page boundar
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jsr swapzp ; copy LFSR code to zero page
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ldx #0
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inx ; X=0
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lda #%00000011 ; create copymask lookup table
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-- ldy #$20
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ora #%10000000
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@ -21,8 +21,9 @@ copymasks = $6200 ; [128 bytes, should not cross page boundar
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asl
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asl
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bne --
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tax ; X=0
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clc
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ldx #0
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-- ldy #$20 ; create address lookup table
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tya
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- sta addrs, x
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@ -32,7 +33,7 @@ copymasks = $6200 ; [128 bytes, should not cross page boundar
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bne -
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txa
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bne --
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; X,Y=0
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jsr $0 ; call LFSR code on zero page
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lda $4000 ; last lousy byte (because LFSR never hits 0)
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@ -45,7 +46,7 @@ swapzp ldx #(end-start-1)
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sty $0, x
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dex
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bpl -
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rts
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rts ; X=#$FF
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start
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!pseudopc 0 {
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@ -16,7 +16,7 @@ addrs=$A100 ; [128 bytes, can be anywhere in main memor
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sbc #1
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dex
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bpl -
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inx
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inx ; X=0
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sta $C005 ; pre-copy SHR SCB and palette
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ldy #0
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@ -28,13 +28,13 @@ addrs=$A100 ; [128 bytes, can be anywhere in main memor
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sta $9F00, y
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iny
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bne -
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; X,Y=0
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jsr $0 ; call LFSR code on zero page
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lda $2000 ; last lousy byte (because LFSR never hits 0)
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sta $2000
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sta $C004 ; restore and exit
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sta $C004
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; fall through to restore and exit
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swapzp ldx #(end-start-1)
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- ldy start, x
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lda $0, x
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