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From: lishka@puff.UUCP (Christopher Lishka)
Newsgroups: net.micro.cbm
Subject: Re: Commodore 64 Stack
Message-ID: <824@puff.UUCP>
Date: Fri, 18-Apr-86 14:21:40 EST
Article-I.D.: puff.824
Posted: Fri Apr 18 14:21:40 1986
Date-Received: Sun, 20-Apr-86 17:04:56 EST
References: <493@unccvax.unccvax.UUCP>
Distribution: net
Organization: U of Wisconsin CS Dept
Lines: 39
Summary: Possible solution and another query...

In article <493@unccvax.unccvax.UUCP>, jeh@unccvax.UUCP (Jeffrey Holman) writes:
>     Can anyone tell me if there is a way to reset the stack pointer in ML?
> I want to move the location of the stack to some bigger area of memory for
> use in a possible compiler.  I am afraid that this is impossible since I
> have been unable to find any reference to the stack pointer location in 
> memory.
>     Any info would be greatly appreciated!!

	As far as I know, the stack space for the 6502 microprocessors
(including the 6510, as in the C-64) has a strict limit of 256 bytes.  I
believe it is located from $0100 to $01ff hex.  This is so that the Stack
Pointer can fit within one byte.  Not very useful, is it?  What I suggest is
to reserve a couple bytes down in zero page for your own Stack Pointer and just
create your own stack.  You could define macros for the 'push' and 'pop'
operations.  OK, so it may not be as fast and efficient as an M.L. implemented
stack, but then again you would have a lot more memory than 256 bytes for stack
space.

>     Also, by the by, has anyone had any luck getting past the screening door
> on board the Heart of Gold in Infocom's 'Hithchikers Guide ...'?  Any hints
> on Marvin??

	Although this probably isn't the best place to get a discussion going
on this game (hell, net.micro.cbm doesn't have THAT much traffic anyway) I
would also be interested in any suggestions on what to do when you've finally
reached the Heart of Gold.  I've been all over this ship and the ONLY points
that I've scored here were negative 'cause I drank the tea substitute (live and
learn :-)  ).  Although I like the humor in this adventure, it has been a lot
harder (and REALLY specific and picky) in how to get anywhere beneficial (and
I've read all four books several times!).  Those who have not read the first
book  be wary in purchasing this game!  Also, can anyone tell me how to go
about attaining a Babel Fish to stick in my ear?  


				Chri Lishka
				U.W Madison

				"You have:
				 no tea..."