Article View: comp.sys.amiga.tech
Article #10376Re: Aztec compiler ineffeciencies
From: Rod Dorman
Date: Sat, 26 Nov 1988 04:33
Date: Sat, 26 Nov 1988 04:33
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In article <3013@sugar.uu.net> karl@sugar.uu.net (Karl Lehenbauer) writes:
>I've been examining the output of Aztec 3.6a and have discovered that it does
>no optimization on divides, such as turning divides by constants into shifts
> asr.l #1,d4
As many compiler writers have found in the past and I'm sure many will
rediscover in the future, this only works for positive values. Try
shifting -1 and you'll get -1 as a result, *not* zero as one would expect.
-- Rod --
Rod Dorman {sun!hoptoad,cmcl2!phri}!dasys1!rodd
Big Electric Cat Public Unix
"The ships hung in the sky in much the same way that bricks don't"
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!watmath!clyde!att!rutgers!mcnc!xanth!hoptoad!dasys1!rodd From: rodd@dasys1.UUCP (Rod Dorman) Newsgroups: comp.sys.amiga.tech Subject: Re: Aztec compiler ineffeciencies Summary: shifts only work for positive values Message-ID: <7949@dasys1.UUCP> Date: 26 Nov 88 04:33:46 GMT References: <3013@sugar.uu.net> Reply-To: rodd@dasys1.UUCP (Rod Dorman) Organization: What me organized ?! Lines: 13