A89: Re: operation size?

To: <assembly-89@lists.ticalc.org>
Subject: A89: Re: operation size?
From: "Dux Gregis" <assets@eden.rutgers.edu>
Date: Thu, 3 Dec 1998 18:49:59 -0500
Delivered-To: assembly-89-outgoing@towerguard.unix.edu.sollentuna.se
Reply-To: assembly-89@lists.ticalc.org




>
>when you afterincrement something, the operation size or something is then
>added to a0 after the instruction is completed
> ie: move (a0)+,d0
>In this case 4 would be added to a0 afterwards...I know this because I read
>it...BUT how do I know what the insruction size is...Why is it 4

it would be four if you said move.l (a0)+,d0 because a long word is four
bytes; if you said move.w (a0)+,d0 it would be two bytes

>
>Also what is unsigned/signed integers?  You used different branch
instructions
>depending on what kind of integer, right?  Or something like that...I'm
just
>typing off the top of my head rightn now...THANKS

A signed integer is an integer that is contextually negative if the highest
bit is set.  So, an unsigned byte would be represented by the range of 0 to
256 and a signed byte would have the range of -128 to 127.  Certain
instructions might treat the operand as signed while others might treat it
as unsigned.

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