RE: [PING] libm functions for x86-64

["Menezes, Evandro" <evandro dot menezes at amd dot com>]

(I apologize for multiple posts, but I'm trying to get all the information out.)

Please, see the files in attach with the accuracy and performance information on both an Opteron (table7o.html) and on a P4 (table7p.html).  Those suffixed routines with "_amd64" are the proposed ones and those suffixed with "_nat64" are the current ones in GLIBC.

As you can see, the proposed routines are generally faster and as or more accurate.  The exceptions being:

- acos, asin, atan2, cos, exp, exp2, hypot, log, pow, sin, tan: slightly less accurate, but better performance over its domain.

- asinh, asinhf, atanf, atan2f, cosf, hypotf, log1p, log1pf, sinf, tanf, tanh: more accurate, but lower performance.

- atan: less accurate and slower; withdrawn.

- fdim, fdimf: as accurate and as fast; withdrawn.

- finite, finitef, modf, modff: as accurate, but slower; withdrawn.

A word on the proposed sin: although the maximum error is much higher than the current one, it is so only at +/- 90Â offset by 1ulp.  This error also shows at the sine as returned by sincos.  You can verify this in the other files in attach (*.summary).  We are working on fixing it.

I'd really appreciate your feedback on this data.  I'll be glad to answer any question you may have.

Thank you,

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Evandro Menezes               AMD            Austin, TX

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Description: libc-fpu-x86_64-data.tgz