A82: Re: i gots a kwestun 4 yous people


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A82: Re: i gots a kwestun 4 yous people




As usual from my favorite Z80 asm book :

P/V : Parity or overflow flag. Parity (P) and overflow (V) shere the same
flag. Logical operations affect this flag with the parity of the result
while arithmetic operations affect this flag with the overflow result.
... If P/V holds overflow, P/V = 1 if the result of the operation produced
on overflow.

So the Z80 has got a way to detect overflows. JR does not support this
flag, but JP does, so you can just use JP PO and JP PE to check for
overflows.

Dines
-----Original Message-----
From: Greg R Milewski <l0rdg0at@juno.com>
To: assembly-82@lists.ticalc.org <assembly-82@lists.ticalc.org>
Date: 3. marts 1998 03:10
Subject: A82: i gots a kwestun 4 yous people


>
>is there any way to detect a register overflow (like "jr o, label") with
>the z80?  it could really help if there was an instruction... else, is
>there a simple routine i can use?
>
>thanx,
>-Greg
>
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_______________________________________

Dines Justesen
Email: dines@post1.com or
       c958362@student.dtu.dk
WWW  : http://www.gbar.dtu.dk/~c958362/
_______________________________________


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