Re: A85: Complement the Z flag?
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Re: A85: Complement the Z flag?
Dines Justesen wrote:
>
> >He is using the zero flag as an error flag on the return from a routine.
> >Let's say that
> >at one place in his routine, the zero flag would be RESET if there were
> >an error. How does he fix this? He needs to do a
> >
> >czf
> >ret z
>
> You can do a RET NZ ! RET,JP,CALL and JR all supports both NZ and Z
> (according to Programming the Z80 by Rodney Zaks). Thats why i can not see
> when you need a czf.
But he wants to set the zf for an error...if he ret nz then it will
return with zf reset, and the program won't know an error happened.
--
Terry Peng <tpeng@geocities.com>
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