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.HasFMA = isSet(12, ecx1)
31	X86.HasSSE41 = isSet(19, ecx1)
32	X86.HasSSE42 = isSet(20, ecx1)
33	X86.HasPOPCNT = isSet(23, ecx1)
34	X86.HasAES = isSet(25, ecx1)
35	X86.HasOSXSAVE = isSet(27, ecx1)
36
37	osSupportsAVX := false
38	// For XGETBV, OSXSAVE bit is required and sufficient.
39	if X86.HasOSXSAVE {
40		eax, _ := xgetbv()
41		// Check if XMM and YMM registers have OS support.
42		osSupportsAVX = isSet(1, eax) && isSet(2, eax)
43	}
44
45	X86.HasAVX = isSet(28, ecx1) && osSupportsAVX
46
47	if maxID < 7 {
48		return
49	}
50
51	_, ebx7, _, _ := cpuid(7, 0)
52	X86.HasBMI1 = isSet(3, ebx7)
53	X86.HasAVX2 = isSet(5, ebx7) && osSupportsAVX
54	X86.HasBMI2 = isSet(8, ebx7)
55	X86.HasERMS = isSet(9, ebx7)
56	X86.HasADX = isSet(19, ebx7)
57}
58
59func isSet(bitpos uint, value uint32) bool {
60	return value&(1<<bitpos) != 0
61}
62