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synced 2024-07-19 04:28:56 +00:00
44 lines
695 B
NASM
44 lines
695 B
NASM
; backup/restore the zero page
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; this is in a separate file so it can be omitted completely if it's not needed.
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_il65_save_zeropage
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lda #%00101111
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sta _il65_zp_backup ; default value for $00
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lda #%00100111
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sta _il65_zp_backup+1 ; default value for $01
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ldx #2
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- lda $00,x
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sta _il65_zp_backup,x
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inx
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bne -
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rts
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_il65_restore_zeropage
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php
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pha
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txa
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pha
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sei
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lda $a0 ; save the current jiffy clock
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sta _il65_zp_backup+$a0
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lda $a1
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sta _il65_zp_backup+$a1
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lda $a2
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sta _il65_zp_backup+$a2
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ldx #0
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- lda _il65_zp_backup,x
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sta $00,x
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inx
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bne -
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cli
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pla
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tax
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pla
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plp
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rts
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_il65_zp_backup
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.fill 256
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