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Use tmp1 instead of y register

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popa clobbers y
This commit is contained in:
Byron Lathi
2023-12-01 22:53:41 -08:00
parent e8452eb98c
commit de804ac3ca
1 changed files with 4 additions and 3 deletions
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7
sw/kernel/devices/rtc.s
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@@ -93,12 +93,13 @@ IRQ_THRESHOLD_3 = $00
; void rtc_set(uint32_t val, uint8_t idx); ; void rtc_set(uint32_t val, uint8_t idx);
.proc _rtc_set .proc _rtc_set
tay ; move cmd to Y sta tmp1 ; store idx in tmp1
ldx #$04 ldx #$04
L1: sty RTC_CMD ; store cmd+idx to CMD L1: lda tmp1
sta RTC_CMD ; store cmd+idx to CMD
jsr popa ; pop 1 byte of argument jsr popa ; pop 1 byte of argument
sta RTC_DAT ; write it to data sta RTC_DAT ; write it to data
iny ; increase index inc tmp1 ; increase index
dex dex
bne L1 ; repeat 4 times bne L1 ; repeat 4 times
rts rts