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From: jesup@pawl19.pawl.rpi.edu (Randell E. Jesup)
Newsgroups: comp.arch
Subject: Re: 16 & 32 bit vs 32 bit only instructions for RISC.
Message-ID: <449@imagine.PAWL.RPI.EDU>
Date: 1 Mar 88 05:54:58 GMT
References: <9651@steinmetz.steinmetz.UUCP> <9678@steinmetz.steinmetz.UUCP> <2574@im4u.UUCP> <2116@saturn.ucsc.edu>
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In article <2116@saturn.ucsc.edu> haynes@ucscc.UCSC.EDU (Jim Haynes) writes:
>I'm glad somebody brought this up, and while we're also at it let's debate
>the value of including 16 bit data types in RISC machines.  A variety
>of data sizes slows a machine down almost as much as a variety of
>instruction sizes.  I was rather surprised to see that Sun included
>16-bit data in SPARC in this day and age of cheap memory.  8-bit data
>has the obvious utility for character strings; but do we really need
>16-bit integers anymore?

	One reason should be enough: compatibility.  If you want another:
Ram space.  Ram, especially for RISC computers, is less than cheap.  Priced
any 20-ns SRAMs lately?  Also note that DRAM prices are goin UP lately, in
contradiction to all established precedent.

	And no, being able to load and store halfwords doesn't really
slow a machine down.  All internal operations can be done in natural word
size.

     //	Randell Jesup			      Lunge Software Development
    //	Dedicated Amiga Programmer            13 Frear Ave, Troy, NY 12180
 \\//	beowulf!lunge!jesup@steinmetz.UUCP    (518) 272-2942
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