65 lines
1.1 KiB
NASM
65 lines
1.1 KiB
NASM
; -*-asm-*-
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include(`common.m4')
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define(ticks_, 00)
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BRA r :reset
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BRA r :irq
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;;; begin irq
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irq: PHA s
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LDA a T1CL
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DEC zp ticks_
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PLA s
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RTI s
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;;; end irq
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reset: LDX # ff
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TXS i
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LDA # %10000000 ;; Set pins 0-7 on Port B to Output
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STA a DDRA
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JSR a :continuous
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count: LDA # 25
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STA zp ticks_
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loop: LDA zp ticks_
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BPL r :loop
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LDA # %10000000
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EOR a PORTA
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STA a PORTA
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BRA r :count
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;;; begin continuous
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continuous: LDA # %01000000
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STA a ACR
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LDA # 0e
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STA a T1CL
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LDA # 27
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STA a T1CH
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LDA # %11000000
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STA a IER
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CLI i
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RTS s
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;;; end continuous
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;;; begin oneshot
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oneshot: LDA # %00000000
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STA a ACR
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LDA # 50
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STA a T1CL
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LDA # c3
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STA a T1CH
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_oneshot: BIT a IFR
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BVC r :_oneshot ; IFR[6]==0
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LDA a T1CL ; clear IFR[6]
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RTS s
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;;; end oneshot
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