| // Copyright 2017 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| // +build 386 amd64 amd64p32 |
| |
| package cpu |
| |
| const CacheLineSize = 64 |
| |
| // cpuid is implemented in cpu_x86.s. |
| func cpuid(eaxArg, ecxArg uint32) (eax, ebx, ecx, edx uint32) |
| |
| // xgetbv with ecx = 0 is implemented in cpu_x86.s. |
| func xgetbv() (eax, edx uint32) |
| |
| func init() { |
| maxId, _, _, _ := cpuid(0, 0) |
| |
| if maxId < 1 { |
| return |
| } |
| |
| _, _, ecx1, edx1 := cpuid(1, 0) |
| X86.HasSSE2 = isSet(26, edx1) |
| |
| X86.HasSSE3 = isSet(0, ecx1) |
| X86.HasPCLMULQDQ = isSet(1, ecx1) |
| X86.HasSSSE3 = isSet(9, ecx1) |
| X86.HasSSE41 = isSet(19, ecx1) |
| X86.HasSSE42 = isSet(20, ecx1) |
| X86.HasPOPCNT = isSet(23, ecx1) |
| X86.HasAES = isSet(25, ecx1) |
| X86.HasOSXSAVE = isSet(27, ecx1) |
| |
| osSupportsAVX := false |
| // For XGETBV, OSXSAVE bit is required and sufficient. |
| if X86.HasOSXSAVE { |
| eax, _ := xgetbv() |
| // Check if XMM and YMM registers have OS support. |
| osSupportsAVX = isSet(1, eax) && isSet(2, eax) |
| } |
| |
| X86.HasAVX = isSet(28, ecx1) && osSupportsAVX |
| |
| if maxId < 7 { |
| return |
| } |
| |
| _, ebx7, _, _ := cpuid(7, 0) |
| X86.HasBMI1 = isSet(3, ebx7) |
| X86.HasAVX2 = isSet(5, ebx7) && osSupportsAVX |
| X86.HasBMI2 = isSet(8, ebx7) |
| X86.HasERMS = isSet(9, ebx7) |
| } |
| |
| func isSet(bitpos uint, value uint32) bool { |
| return value&(1<<bitpos) != 0 |
| } |
