[A83] Re: Explaining the stack for registers

To: assembly-83@lists.ticalc.org
Subject: [A83] Re: Explaining the stack for registers
From: "Dan Weiss" <dwedit@hotmail.com>
Date: Thu, 16 Aug 2001 14:47:03 -0500
Reply-To: assembly-83@lists.ticalc.org

Also note that CALL and RET also use the same stack...

You can't:

  push hl
  call Routine

Routine:
  pop hl
  ret

If you did that, HL would contain the address of the code after the call, 
and the RET would jump to the value of the pushed HL.  In other words, 
CRASH.

(Unless of course HL contained a valid executable address...)

>From: "TypeR unknown" <typerfuture@hotmail.com>
>Reply-To: assembly-83@lists.ticalc.org
>To: assembly-83@lists.ticalc.org
>Subject: [A83] Re: Explaining the stack for registers
>Date: Thu, 16 Aug 2001 19:51:46 +0200
>MIME-Version: 1.0
>X-Originating-IP: [194.69.26.241]
>Received: from [195.67.128.9] by hotmail.com (3.2) with ESMTP id 
>MHotMailBD45533A006940043156C343800910050; Thu, 16 Aug 2001 10:52:12 -0700
>Received: from towerguard. (mx-1.sollentuna.net [195.67.128.9])by 
>mx-1.sollentuna.net (Postfix) with ESMTPid D3C331800F; Thu, 16 Aug 2001 
>19:51:49 +0200 (CEST)
>Received: with LISTAR (v1.0.0; list assembly-83); Thu, 16 Aug 2001 19:51:49 
>+0200 (CEST)
>Received: from hotmail.com (f116.pav2.hotmail.com [64.4.37.116])by 
>mx-1.sollentuna.net (Postfix) with ESMTP id 54C5F1800Bfor 
><assembly-83@lists.ticalc.org>; Thu, 16 Aug 2001 19:51:48 +0200 (CEST)
>Received: from mail pickup service by hotmail.com with Microsoft SMTPSVC; 
>Thu, 16 Aug 2001 10:51:46 -0700
>Received: from 194.69.26.241 by pv2fd.pav2.hotmail.msn.com with HTTP;	Thu, 
>16 Aug 2001 17:51:46 GMT
>From assembly-83-bounce@lists.ticalc.org Thu, 16 Aug 2001 10:52:13 -0700
>Delivered-To: lists.ticalc-assembly-83@mx-1.sollentuna.net
>Message-ID: <F116nPSsYFbRYQ8P6rb0000d8e6@hotmail.com>
>X-OriginalArrivalTime: 16 Aug 2001 17:51:46.0496 (UTC) 
>FILETIME=[1E0B9400:01C1267C]
>X-listar-version: Listar v1.0.0
>Sender: assembly-83-bounce@lists.ticalc.org
>Errors-To: assembly-83-bounce@lists.ticalc.org
>X-original-sender: typerfuture@hotmail.com
>Precedence: bulk
>X-list: assembly-83
>
>
>Ahh I understand much better now!!!
>I thought that every register that can be pushed had it's own stack, so I
>was a bit confused when it appeared that the content of one register could
>somehow be loaded in another register, but I understand very well now, 
>thank
>you very much for your explanation!
>
>
> >From: "Michael Vincent" <hookman@worldnet.att.net>
> >Reply-To: assembly-83@lists.ticalc.org
> >To: <assembly-83@lists.ticalc.org>
> >Subject: [A83] Re: Explaining the stack for registers
> >Date: Thu, 16 Aug 2001 10:12:18 -0700
> >
> >
> >First, "if you push af and then pop bc" the contents will be in BC, not 
>AF.
> >The reason for this is when you push a register, the values in it are put
> >on
> >the stack, not the name. So if you push af then the value of A and the
> >flags
> >byte are on the stack. You can then pop whatever you want. If you pop bc
> >then the 2 bytes on the stack from the push af will be put in BC. (B will
> >have what was in A, and C will have what was in F).
> >
> >There is no limit to how many times a register can be pushed, except on 
>the
> >TI-83 Plus (and I think 83) the stack is only 400 bytes. After that you
> >will
> >corrupt RAM. The TI-OS uses a few bytes, but you have like 100 pushes or
> >more you could do before you overflowed the stack.
> >
> >
> >Michael Vincent
> >Detached Solutions - www.detacheds.com
> >Radical Software - www.radicalsoft.org
> >
> >----- Original Message -----
> >From: "TypeR unknown" <typerfuture@hotmail.com>
> >To: <assembly-83@lists.ticalc.org>
> >Sent: Thursday, August 16, 2001 10:00 AM
> >Subject: [A83] Explaining the stack for registers
> >
> >
> > >
> > > After reading the FAQ in AsmGuru there is a question about the stack
> >with
> > > registers. It says that (if I remember correctly) "if you push af and
> >then
> > > pop bc, the contents of bc will be in af"
> > >
> > > WHY ???
> > >
> > > I see no logic in that, and unfortunatly it isn't explained in AsmGuru
> > > either, so here I am :)
> > >
> > > Also I would like to know how many times a register can be pushed.
> > >
> > >
> > >
> > >
> > > _________________________________________________________________
> > > Get your FREE download of MSN Explorer at
> >http://explorer.msn.com/intl.asp
> > >
> > >
> > >
> >
> >
> >
>
>
>_________________________________________________________________
>Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp
>
>
>


_________________________________________________________________
Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp