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Diffstat (limited to 'src/internal/cpu/cpu_x86.go')
| -rw-r--r-- | src/internal/cpu/cpu_x86.go | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/src/internal/cpu/cpu_x86.go b/src/internal/cpu/cpu_x86.go new file mode 100644 index 0000000..ba6bf69 --- /dev/null +++ b/src/internal/cpu/cpu_x86.go @@ -0,0 +1,163 @@ +// 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 + +package cpu + +const CacheLinePadSize = 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) + +const ( + // edx bits + cpuid_SSE2 = 1 << 26 + + // ecx bits + cpuid_SSE3 = 1 << 0 + cpuid_PCLMULQDQ = 1 << 1 + cpuid_SSSE3 = 1 << 9 + cpuid_FMA = 1 << 12 + cpuid_SSE41 = 1 << 19 + cpuid_SSE42 = 1 << 20 + cpuid_POPCNT = 1 << 23 + cpuid_AES = 1 << 25 + cpuid_OSXSAVE = 1 << 27 + cpuid_AVX = 1 << 28 + + // ebx bits + cpuid_BMI1 = 1 << 3 + cpuid_AVX2 = 1 << 5 + cpuid_BMI2 = 1 << 8 + cpuid_ERMS = 1 << 9 + cpuid_ADX = 1 << 19 +) + +var maxExtendedFunctionInformation uint32 + +func doinit() { + options = []option{ + {Name: "adx", Feature: &X86.HasADX}, + {Name: "aes", Feature: &X86.HasAES}, + {Name: "avx", Feature: &X86.HasAVX}, + {Name: "avx2", Feature: &X86.HasAVX2}, + {Name: "bmi1", Feature: &X86.HasBMI1}, + {Name: "bmi2", Feature: &X86.HasBMI2}, + {Name: "erms", Feature: &X86.HasERMS}, + {Name: "fma", Feature: &X86.HasFMA}, + {Name: "pclmulqdq", Feature: &X86.HasPCLMULQDQ}, + {Name: "popcnt", Feature: &X86.HasPOPCNT}, + {Name: "sse3", Feature: &X86.HasSSE3}, + {Name: "sse41", Feature: &X86.HasSSE41}, + {Name: "sse42", Feature: &X86.HasSSE42}, + {Name: "ssse3", Feature: &X86.HasSSSE3}, + + // These capabilities should always be enabled on amd64: + {Name: "sse2", Feature: &X86.HasSSE2, Required: GOARCH == "amd64"}, + } + + maxID, _, _, _ := cpuid(0, 0) + + if maxID < 1 { + return + } + + maxExtendedFunctionInformation, _, _, _ = cpuid(0x80000000, 0) + + _, _, ecx1, edx1 := cpuid(1, 0) + X86.HasSSE2 = isSet(edx1, cpuid_SSE2) + + X86.HasSSE3 = isSet(ecx1, cpuid_SSE3) + X86.HasPCLMULQDQ = isSet(ecx1, cpuid_PCLMULQDQ) + X86.HasSSSE3 = isSet(ecx1, cpuid_SSSE3) + X86.HasSSE41 = isSet(ecx1, cpuid_SSE41) + X86.HasSSE42 = isSet(ecx1, cpuid_SSE42) + X86.HasPOPCNT = isSet(ecx1, cpuid_POPCNT) + X86.HasAES = isSet(ecx1, cpuid_AES) + + // OSXSAVE can be false when using older Operating Systems + // or when explicitly disabled on newer Operating Systems by + // e.g. setting the xsavedisable boot option on Windows 10. + X86.HasOSXSAVE = isSet(ecx1, cpuid_OSXSAVE) + + // The FMA instruction set extension only has VEX prefixed instructions. + // VEX prefixed instructions require OSXSAVE to be enabled. + // See Intel 64 and IA-32 Architecture Software Developer’s Manual Volume 2 + // Section 2.4 "AVX and SSE Instruction Exception Specification" + X86.HasFMA = isSet(ecx1, cpuid_FMA) && X86.HasOSXSAVE + + 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(eax, 1<<1) && isSet(eax, 1<<2) + } + + X86.HasAVX = isSet(ecx1, cpuid_AVX) && osSupportsAVX + + if maxID < 7 { + return + } + + _, ebx7, _, _ := cpuid(7, 0) + X86.HasBMI1 = isSet(ebx7, cpuid_BMI1) + X86.HasAVX2 = isSet(ebx7, cpuid_AVX2) && osSupportsAVX + X86.HasBMI2 = isSet(ebx7, cpuid_BMI2) + X86.HasERMS = isSet(ebx7, cpuid_ERMS) + X86.HasADX = isSet(ebx7, cpuid_ADX) +} + +func isSet(hwc uint32, value uint32) bool { + return hwc&value != 0 +} + +// Name returns the CPU name given by the vendor. +// If the CPU name can not be determined an +// empty string is returned. +func Name() string { + if maxExtendedFunctionInformation < 0x80000004 { + return "" + } + + data := make([]byte, 0, 3*4*4) + + var eax, ebx, ecx, edx uint32 + eax, ebx, ecx, edx = cpuid(0x80000002, 0) + data = appendBytes(data, eax, ebx, ecx, edx) + eax, ebx, ecx, edx = cpuid(0x80000003, 0) + data = appendBytes(data, eax, ebx, ecx, edx) + eax, ebx, ecx, edx = cpuid(0x80000004, 0) + data = appendBytes(data, eax, ebx, ecx, edx) + + // Trim leading spaces. + for len(data) > 0 && data[0] == ' ' { + data = data[1:] + } + + // Trim tail after and including the first null byte. + for i, c := range data { + if c == '\x00' { + data = data[:i] + break + } + } + + return string(data) +} + +func appendBytes(b []byte, args ...uint32) []byte { + for _, arg := range args { + b = append(b, + byte((arg >> 0)), + byte((arg >> 8)), + byte((arg >> 16)), + byte((arg >> 24))) + } + return b +} |