[Coco] assembly question

William Astle lost at l-w.ca
Sun Aug 9 12:46:58 EDT 2015


Actually, the logic operations affect C. Shift and arithmetic operations 
do. So EORA doesn't affect C but SUBA does.

If you want to know what instructions affect C, check the data sheet for 
the 6809 (or a good instruction set reference).

On 2015-08-09 05:43, K. Pruitt wrote:
> So the carry flag is being set, inadvertently in this case, by
>
>             eora  -5,x                   ; get changed bits from Ctrl Reg
>             suba  #$60                ; did expected bits change?
>
> both of these lines?
>
> If I understand it correctly, math and logic operands effect the carry
> flag?



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