Re: A89: Re: and now a REAL ASM question!

To: <assembly-89@lists.ticalc.org>
Subject: Re: A89: Re: and now a REAL ASM question!
From: "Thayne Miller" <yomaster@inconnect.com>
Date: Thu, 24 Sep 1998 18:02:20 -0600
Delivered-To: assembly-89-outgoing@towerguard.unix.edu.sollentuna.se
Reply-To: assembly-89@lists.ticalc.org


Ahh!  I see!  Thank you SO much for clearing this up for me.  =)

>
>>ok, so do you mean that after the "lea" instruction, AO will POINT to the
>>beginning of the string?  And therefore if I use "move" it will actually
>>load the first byte of the STRING into A0 rather than the address of the
>>string?  I kind of understand, but I just wanted to make sure...  so if I
>>did:
>>
>>lea  (A0),A1
>>
>>and A0 was "1000", then A1 would be "1000" rather than the actual WORD at
>>memory adress 1000?  Or am I completely screwed up?
>>
>>
>
>lea (A0),A1 would be pointless, since it would be the same as movea A0,A1
>
>The point of lea is to load _effective address_ of the operand into the
>second operand.  The reason you need to do lea string(pc), A1 is because
>you want to load the address of string(pc) -- the # of bytes to the string
>plus the program counter -- into A1, instead of moving the contents of it
>by using the move instruction.
>
>Hope this helps!
>
>-Mark
>
>