To: djgpp AT delorie DOT com
Subject: Re: DJGPP V2.01 loop unrolling bug]
Message-ID: <19961029.194317.8207.0.chambersb@juno.com>
References: <199610211814 DOT OAA10948 AT delorie DOT com> <54t1pb$77r AT news DOT service DOT uci DOT edu>
	<551fg8$mk4 AT lastactionhero DOT rs DOT itd DOT umich DOT edu>
From: chambersb AT juno DOT com (Benjamin D Chambers)
Date: Mon, 28 Oct 1996 22:43:10 EST


On Mon, 28 Oct 96 05:14:44 GMT vecna AT engin DOT umich DOT edu (Jimmy Wan) writes:
>In article <54t1pb$77r AT news DOT service DOT uci DOT edu>,
>   beppu AT rigel DOT oac DOT uci DOT edu (John Beppu) wrote:
>>In article <199610211814 DOT OAA10948 AT delorie DOT com>,
>>Troy D. Van Horn <trvanhor AT UCollege DOT edu> wrote:
>>>Aren't loop unrolling and strenth reducing two different
>>>optimizations?
>>
>>  What is __strength reduction__?  I've never heard of
>>  this optimzation technique before.
>
>Strength reduction is the use of simpler and less complex instructions
>to do the same thing.  For example, instead of multiplying an integer
>by 2, left shift it by 1.  Much much faster.  Personally, I explicitly
>use the shifts in my code anyway.  BTW, anyone have a clock cycle
>listing for 486's, P5's and P6's?  Or know where I can get one?  I 
>have
>one for the 8086 and the 80186 and those really aren't going to do me
>any good...
>
>Jimmy Wan               University of Michigan-Computer Engineering
>Turtle Beach Maui Page  http://www-personal.umich.edu/~vecna/maui.html
>Device Driver
Page	http://www-personal.umich.edu/~vecna/drivers.html
>
the pcgpe has a listing of clock cycles of the 8086-80486.
ftp://ftp.netcom.com/pub/profile/game-dev/tools should have it.