Message-ID: <32E2D80E.7760@gbrmpa.gov.au>
Date: Mon, 20 Jan 1997 10:27:26 +0800
From: Leath Muller <leathm AT gbrmpa DOT gov DOT au>
Reply-To: leathm AT gbrmpa DOT gov DOT au
Organization: Great Barrier Reef Marine Park Authority
MIME-Version: 1.0
To: "G.P. Tootell" <gpt20 AT thor DOT cam DOT ac DOT uk>
CC: djgpp AT delorie DOT com
Subject: Re: floating point is... fast???
References: <5brd2e$dap AT lyra DOT csx DOT cam DOT ac DOT uk>
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> while using the profiler on some code i had written i noticed that changing a
> floating point multiply to an unsigned multiply of 2 longs turned out to be
> slower. in fact floating point multiply appears to be faster than ordinary
> integer multiply for any case. is this actually true? and if so is there any
> reason i shouldn't just change every multiply in my code to make sure it's
> floating point?

Yes, floating point is faster because imul and idiv use the floating
point unit to do the operations - thus an integer mul/divide has the
overhead of converting the int -> float, div/mul, then float -> int.
Whereas the floating point calculations just do the div/mul...

Leathal.