tzhash/tz/cpuid_x86.go
Evgenii Stratonikov f613ab2c25 Implement matrix multiplication with pure Go
Set suitable backend for GF127 arithmetic for Concat(), Sum() etc.
2019-10-09 12:31:47 +03:00

69 lines
2.2 KiB
Go

// Copyright (c) 2009 The Go Authors. All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
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//
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// distribution.
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// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// +build 386 amd64 amd64p32
package tz
const (
bitOSXSAVE = 1 << 27
bitAVX = 1 << 28
bitAVX2 = 1 << 5
)
func setFeatures() {
maxID, _, _, _ := cpuid(0, 0)
if maxID < 1 {
return
}
_, _, ecx1, _ := cpuid(1, 0)
hasOSXSAVE = isSet(ecx1, bitOSXSAVE)
osSupportsAVX := false
if hasOSXSAVE {
eax, _ := xgetbv()
osSupportsAVX = isSet(eax, 1<<1) && isSet(eax, 1<<2)
}
hasAVX = isSet(ecx1, bitAVX) && osSupportsAVX
if maxID < 7 {
return
}
_, ebx7, _, _ := cpuid(7, 0)
hasAVX2 = isSet(ebx7, bitAVX2) && osSupportsAVX
}
func isSet(hwc uint32, value uint32) bool {
return hwc&value != 0
}
func cpuid(eaxArg, ecxArg uint32) (eax, ebx, ecx, edx uint32)
func xgetbv() (eax, edx uint32)