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math.vectors.simd: Improved documentation

db4
Slava Pestov 2009-09-23 03:14:06 -05:00
parent 43acea72b9
commit f017f8904b
1 changed files with 7 additions and 3 deletions
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basis/math/vectors/simd/simd-docs.factor
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@ -17,13 +17,17 @@ $nl
"There should never be any reason to use " { $link "math.vectors.simd.intrinsics" } " directly, but they too have a straightforward, but lower-level, interface." ;
ARTICLE: "math.vectors.simd.support" "Supported SIMD instruction sets and operations"
"At present, the SIMD support makes use of SSE, SSE2 and a few SSE3 instructions on x86 CPUs."
"At present, the SIMD support makes use of a subset of SSE up to SSE4.1. The subset used depends on the current CPU type."
$nl
"SSE1 only supports single-precision SIMD (" { $snippet "float-4" } " and " { $snippet "float-8" } ")."
$nl
"SSE2 introduces double-precision and integer SIMD."
"SSE2 introduces double-precision SIMD (" { $snippet "double-2" } " and " { $snippet "double-4" } ") and integer SIMD (all types). Integer SIMD in missing a few features, in particular the " { $link vmin } " and " { $link vmax } " operations only work on " { $snippet "uchar-16" } " and " { $snippet "short-8" } "."
$nl
"SSE3 introduces horizontal adds (summing all components of a single vector register), which is useful for computing dot products. Where available, SSE3 operations are used to speed up " { $link sum } ", " { $link v. } ", " { $link norm-sq } ", " { $link norm } ", and " { $link distance } ". If SSE3 is not available, software fallbacks are used for " { $link sum } " and related words."
"SSE3 introduces horizontal adds (summing all components of a single vector register), which is useful for computing dot products. Where available, SSE3 operations are used to speed up " { $link sum } ", " { $link v. } ", " { $link norm-sq } ", " { $link norm } ", and " { $link distance } "."
$nl
"SSSE3 introduces " { $link vabs } " for " { $snippet "char-16" } ", " { $snippet "short-8" } " and " { $snippet "int-4" } "."
$nl
"SSE4.1 introduces " { $link vmin } " and " { $link vmax } " for all remaining integer types."
$nl
"On PowerPC, or older x86 chips without SSE, software fallbacks are used for all high-level vector operations. SIMD code can run with no loss in functionality, just decreased performance."
$nl