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- .define Adi4
- .sect .text
- .sect .rom
- .sect .data
- .sect .bss
- .sect .text
- ! This subroutine adds two fourbyte integers, which are on the stack.
- ! The addresses are initiated by the subroutine Addsub.
- ! Also the loopvariable (register X) is initiated by that routine.
- ! The result is pushed back onto the stack
- Adi4:
- jsr Addsub ! initiate addresses
- clc
- 1: lda (ADDR+2),y ! get byte first operand
- adc (ADDR),y ! add to byte second operand
- sta (ADDR+2),y ! push on real stack
- iny
- inx
- bne 1b ! do it 4 times
- rts
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