1// Copyright 2017 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5// +build 386 amd64 amd64p32
6
7package cpu
8
9const CacheLineSize = 64
10
11// cpuid is implemented in cpu_x86.s.
12func cpuid(eaxArg, ecxArg uint32) (eax, ebx, ecx, edx uint32)
13
14// xgetbv with ecx = 0 is implemented in cpu_x86.s.
15func xgetbv() (eax, edx uint32)
16
17func init() {
18	maxId, _, _, _ := cpuid(0, 0)
19
20	if maxId < 1 {
21		return
22	}
23
24	_, _, ecx1, edx1 := cpuid(1, 0)
25	X86.HasSSE2 = isSet(26, edx1)
26
27	X86.HasSSE3 = isSet(0, ecx1)
28	X86.HasPCLMULQDQ = isSet(1, ecx1)
29	X86.HasSSSE3 = isSet(9, ecx1)
30	X86.HasSSE41 = isSet(19, ecx1)
31	X86.HasSSE42 = isSet(20, ecx1)
32	X86.HasPOPCNT = isSet(23, ecx1)
33	X86.HasAES = isSet(25, ecx1)
34	X86.HasOSXSAVE = isSet(27, ecx1)
35
36	osSupportsAVX := false
37	// For XGETBV, OSXSAVE bit is required and sufficient.
38	if X86.HasOSXSAVE {
39		eax, _ := xgetbv()
40		// Check if XMM and YMM registers have OS support.
41		osSupportsAVX = isSet(1, eax) && isSet(2, eax)
42	}
43
44	X86.HasAVX = isSet(28, ecx1) && osSupportsAVX
45
46	if maxId < 7 {
47		return
48	}
49
50	_, ebx7, _, _ := cpuid(7, 0)
51	X86.HasBMI1 = isSet(3, ebx7)
52	X86.HasAVX2 = isSet(5, ebx7) && osSupportsAVX
53	X86.HasBMI2 = isSet(8, ebx7)
54	X86.HasERMS = isSet(9, ebx7)
55}
56
57func isSet(bitpos uint, value uint32) bool {
58	return value&(1<<bitpos) != 0
59}
60