Path: utzoo!utgpu!attcan!uunet!steinmetz!davidsen
From: davidsen@steinmetz.ge.com (William E. Davidsen Jr)
Newsgroups: comp.arch
Subject: Re: using (ugh!  yetch!) assembler
Message-ID: <11674@steinmetz.ge.com>
Date: 28 Jul 88 18:06:42 GMT
References: <6341@bloom-beacon.MIT.EDU> <60859@sun.uucp> <474@m3.mfci.UUCP> <2442@pt.cs.cmu.edu> <20894@beta.lanl.gov>
Reply-To: davidsen@crdos1.UUCP (bill davidsen)
Organization: General Electric CRD, Schenectady, NY
Lines: 21

In article <20894@beta.lanl.gov> jlg@beta.lanl.gov (Jim Giles) writes:

| I've never seen switching compilers do better than recoding in assembly.
| I guess it could happen if you have a bad programmer do your assembly code.

  How about a large program? A good C compiler will find common
subexpressions, partial results, etc. Even a good assembly programmer
won't rescan the whole program after every change to see if any common
subexpressions can be eliminated.

  In the same vein, I once had a program which was a little too large
and slow. I changed many of the procedures to macros, and generated the
code inline. This allowed the (VAX-11) C compiler to find more common
stuff, dead loops, etc, and produce code which was about 20% faster, and
could still be converted back to procedures by removing one include
statement. Unfortunately the program stayed about the same size, but I
lived with it.
-- 
	bill davidsen		(wedu@ge-crd.arpa)
  {uunet | philabs | seismo}!steinmetz!crdos1!davidsen
"Stupidity, like virtue, is its own reward" -me