Re: A89: Re: Stupid Question

To: assembly-89@lists.ticalc.org
Subject: Re: A89: Re: Stupid Question
From: S43R80@aol.com
Date: Mon, 22 Feb 1999 22:59:39 EST
Delivered-To: assembly-89-outgoing@towerguard.unix.edu.sollentuna.se
Delivered-To: assembly-89@lists.ticalc.org
Reply-To: assembly-89@lists.ticalc.org


In a message dated 99-02-22 22:50:04 EST, you write:

<< 
 It depends on how much to push to the stack...
  >>


Elaborating...If you push a byte then you add 1...If you pust a word then you
add 2...If you push a longword/doubleword then you add 4...

Taken from helloworld:  //you should have a look
    move.w   #4,-(a7)               ; move the first param to the stack
    lea      string(pc),a0          ; move adress of string to the stack
    move.l   a0,-(a7)
    move.w   #0,-(a7)               ; push position
    move.w   #0,-(a7)               ; push position
    jsr      tios::DrawStrXY        ; call the DrawStrXY ROM function
    add.l    #10,a7                 ; restore the stack pointer

     First a word is pushed then a longword  then two words are
pushed//2+4+2+2=10 so you have to add 10 to the stack...you could also do it
the other way: lea 10(a7),a7 which i think is like 1 byte shorter or something

Follow-Ups:

A89: lea vs. add.l

From: Olle Hedman <oh@hem.passagen.se>