Apple-2-SW/Play-BTc
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Fixed cycle count for non-page-crossing byte read.

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Oliver Schmidt 2018-08-10 14:56:44 +02:00 committed by GitHub
parent 09849e9541
commit 10dd1e4b7f
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1 changed files with 13 additions and 7 deletions
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play-btc.s
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@ -36,7 +36,10 @@ QUIT: .byte $04 ; param_count
PLAY:
; loop here as long as bits are [F]alse (aka 0)
F_NX: jsr DELAY ; 6 (+13) 19
F_NX: nop ; 2 2
nop ; 2 2
nop ; 2 2
bit $00 ; 3 3
F_RD: lda ($FE),y ; 5 5 5
asl ; 2 2 2
bcs T_1_SW ; 2/3 2
@ -95,11 +98,11 @@ F_6: jsr DELAY ; 6 (+13)
F_7: jsr DELAY ; 6 (+13)
asl ; 2
bcs T_8_SW ; 2/3 2
nop ; 2 2
nop ; 2 2
nop ; 2 2
nop ; 2 2
bcs T_8_SW ; 2/3 2 2
nop ; 2 2 2
nop ; 2 2 2
nop ; 2 2 2
nop ; 2 2 2
F_8: iny ; 2 2 2
bne F_NX ; 2/3 3 = 31 2
@ -190,7 +193,10 @@ F_8_SW: sta $C030 ; 4
; loop here as long as bits are [T]rue (aka 1)
T_NX: jsr DELAY ; 6 (+13)
T_NX: nop ; 2
nop ; 2
nop ; 2
bit $00 ; 3
T_RD: lda ($FE),y ; 5
asl ; 2
bcc F_1_SW ; 2/3