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From: ee161abt@sdcc18.ucsd.EDU (Grobbins)
Newsgroups: net.micro.apple
Subject: Re: //GS addressing and add on memory?
Message-ID: <548@sdcc18.ucsd.EDU>
Date: Sat, 11-Oct-86 18:26:36 EDT
Article-I.D.: sdcc18.548
Posted: Sat Oct 11 18:26:36 1986
Date-Received: Sun, 12-Oct-86 02:08:00 EDT
References: <8610111432.AA01300@ai.wisc.edu>
Reply-To: ee161abt@sdcc18.UUCP (Grobbins)
Organization: U.C. San Diego, Academic Computer Center
Lines: 15

In article <8610111432.AA01300@ai.wisc.edu> neves@AI.WISC.EDU ("David M. Neves") writes:
>I have heard that the //GS has a 16 meg address space but also that it
>breaks memory up in 64K chunks.  What I want to know is can I define
>big arrays (~ 1 megabyte) in C or Pascal or will I be restricted to
>arrays of size 64K (as you often see in IBM languages)?

The 65816 sees memory as 64K banks selected by two 8-bit registers.
(A completely specified address is 8+16=24 bits long.)
Though the Memory Manager in the //gs has no trouble dealing with
chunks of memory larger than 64K, compilers may nevertheless hold
program variables to that limit.  64K is the largest array index the
chip conveniently supports.  (The X and Y registers are 16 bits
long.) 

Grobbins.