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slightly improve sys.waitvsync() on c64

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Irmen de Jong 2021-10-03 21:35:12 +02:00
parent fbef63e150
commit 06b3bf27b5
1 changed files with 3 additions and 5 deletions
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8
compiler/res/prog8lib/c64/syslib.p8
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@ -502,11 +502,9 @@ sys {
; --- busy wait till the next vsync has occurred (approximately), without depending on custom irq handling. ; --- busy wait till the next vsync has occurred (approximately), without depending on custom irq handling.
; note: a more accurate way to wait for vsync is to set up a vsync irq handler instead. ; note: a more accurate way to wait for vsync is to set up a vsync irq handler instead.
%asm {{ %asm {{
- lda c64.RASTER - bit c64.SCROLY
beq - bpl -
- lda c64.RASTER - bit c64.SCROLY
bne -
bit c64.SCROLY
bmi - bmi -
rts rts
}} }}