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Created Variables in ZeroPage to reference addresses

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This commit is contained in:
Samuel Walker 2025-03-21 16:30:44 -06:00
parent 01943c4c8c
commit 48a2749fd7
1 changed files with 31 additions and 27 deletions
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58
main.s
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@ -11,6 +11,11 @@
.segment "STARTUP"
.segment "ZEROPAGE"
InNum: .res 1
BCD: .res 2
TMP: .res 1
NUM: .res 1
.segment "CHARS"
.incbin "./CHR-ROM.bin"
@ -20,21 +25,21 @@ bg_pallets:
.byte $0F, $30, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15
double_dabble:
lda #0
sta $01
sta $02
sta BCD
sta BCD+1
ldx #8
dabble:
; check first digit
lda $01
lda BCD
and #$F
jsr check
sta $03
sta TMP
lda #$F0
and $01
ora $03
sta $01
and BCD
ora TMP
sta BCD
; check second digit
lda $01
lda BCD
and #$F0
lsr
lsr
@ -45,26 +50,25 @@ dabble:
asl
asl
asl
sta $03
sta TMP
lda #$F
and $01
ora $03
sta $01
and BCD
ora TMP
sta BCD
; check third digit
lda $02
lda BCD+1
and #$F
jsr check
sta $03
sta TMP
lda #$F0
and $02
ora $03
sta $02
and BCD+1
ora TMP
sta BCD+1
; Shift
clc
rol $00
rol $01
rol $02
lda $00
rol InNum
rol BCD
rol BCD+1
dex
bne dabble
rts
@ -129,22 +133,22 @@ forever:
jmp forever
nmi:
inc $05
lda $05
sta $00
inc NUM
lda NUM
sta InNum
jsr double_dabble
lda $2002
lda #$20
sta $2006
lda #$20
sta $2006
lda $02
lda BCD+1
and #$F
cmp #0
bne :+
lda #10
: sta $2007
lda $01
lda BCD
and #$F0
lsr
lsr
@ -154,7 +158,7 @@ nmi:
bne :+
lda #10
: sta $2007
lda $01
lda BCD
and #$F
cmp #0
bne :+