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https://github.com/MiSTer-devel/CDi_MiSTer.git
synced 2026-04-19 03:04:19 +00:00
65 lines
961 B
NASM
65 lines
961 B
NASM
section .text
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org $400000
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vector:
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dc.l $1234
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dc.l main
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main:
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move.l #cdicirq,$200
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move #$2000,SR
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move.w #$2480,$303FFC ; IRQ vector
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move.w #$0023,$303C00 ; Command Register = Reset Mode 1
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move.w #$8000,$303FFE ; Data buffer
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move.w #$2480,$303FFC ; Interrupt Vector
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move.w #$0029,$303C00 ; Read Mode 1
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move.l #$0021600,$303C02 ; Time Register
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move.w #$C000,$303FFE ; Start the Read
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move.l #$2000,A3
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move.b #'A',$80002019
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jsr waitforirq
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move.b #'B',$80002019
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jsr waitforirq
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move.b #'C',$80002019
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move.w #$0000,$303FFE ; Stop the Read
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move.w #$C000,$303FFE ; Start the Read
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jsr waitforirq
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jsr waitforirq
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endless:
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bra endless
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wait:
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add #-1,d0
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bne wait
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rts
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waitforirq:
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move #0,d0
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waitforirqloop:
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cmp #0,d0
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beq waitforirqloop
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move.b #'O',$80002019
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rts
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cdicirq:
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move.b #'I',$80002019
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move.w $303FF4,d0 ; clear flags on ABUFD
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move.w $303FF6,d0 ; clear flags on XBUF
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;move.b #$92,$80004005
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move #1,d0
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rte
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