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From: | Nathan Hurst |
Subject: | Re: [Devel] Question about optimizing FT_MulFix. |
Date: | Tue, 1 May 2001 00:48:59 +1000 (EST) |
As a followup: I'm surprised about the slowness of version 5 - the powerpc compiler writer's manual makes a big deal about avoiding branches when possible using the condition code registers(which aren't used by gcc) and the select instructions(a machine code equivalent of c=(condition register)?a:b). If I knew how to compile ppc asm under gcc I would implement 5 using these tools and see how it fares. Also worth trying would be to run the test on MacOS using the FixMul routine provided in the std libs which is presumably fairly carefully optimised as it is used lots in the quickdraw routines. It's of course questionable whether there is much point in spending any more time on this. njh
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