Path: utzoo!mnetor!uunet!lll-winken!lll-lcc!ames!hao!gatech!linus!bs
From: bs@linus.UUCP (Robert D. Silverman)
Newsgroups: comp.arch
Subject: Re: RISC is a nasty no-no!
Message-ID: <25723@linus.UUCP>
Date: 29 Feb 88 19:03:11 GMT
References: <179@wsccs.UUCP: <696@nuchat.UUCP: <284@scdpyr.UUCP> <25699@linus.UUCP> <11199@duke.cs.duke.edu>
Reply-To: bs@gauss.UUCP (Robert D. Silverman)
Organization: The MITRE Corporation, Bedford MA
Lines: 26

In article <11199@duke.cs.duke.edu: dfk@duke.cs.duke.edu (David Kotz) writes:
:> There's something about RISC architectures in general that I find 
:> confusing. Since they (read SPARC or equivalent) have no integer multiply
:> instructions, any code which has a fair number of these is going to
:> be slow. This would include any program which had access to 2-D arrays
:> since one must do multiplications (unless the array sizes are a convenient
:> power of 2) to get the array indices right. ...
:> Bob Silverman
:
:Multiplication is not necessary to access 2-D arrays if the array is
:set up like most arrays in C, where each row is a typical vector and
:the 2-D array is just a vector of pointers to each row vector. Then

etc.


This isn't intended as a flame but your response is too 'language dependent'.
Not all code is written in a language that has pointers. There are many
numerical packages out there, written in FORTRAN (yech). It not only
doesn't have pointers, but it also stores things in column-major rather than
row-major order.

Please. We are discussing hardware, not software. Let's not introduce
language dependencies. Your solution also fails to address those numerical
problems that have multiplies in them.

Bob