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Re: Sine and Cosine Accuracy
- From: Scott Robert Ladd <scott dot ladd at coyotegulch dot com>
- To: "Menezes, Evandro" <evandro dot menezes at amd dot com>
- Cc: Richard Henderson <rth at redhat dot com>, gcc at gcc dot gnu dot org
- Date: Thu, 26 May 2005 20:42:25 -0400
- Subject: Re: Sine and Cosine Accuracy
- References: <84EA05E2CA77634C82730353CBE3A843028F45C1@SAUSEXMB1.amd.com>
Menezes, Evandro wrote:
> Besides, you're also comparing 80-bit calculations with 64-bit
> calculations, not only the accuracy of sin and cos. Try using
> -ffloat-store along with -mfpmath=387 and see yet another set of
> results. At the end of the day, which one do you trust? I wouldn't
> trust my check balance to x87 microcode... ;-)
I wouldn;t trust my bank accounts to the x87 under any circumstances;
anyone doing exact math should be using fixed-point.
Different programs have different requirements. I don't understand why
GCC needs to be one-size fits all, when it could be *better* than the
competition by taking a broader and more flexible view.
..Scott