288 lines
12 KiB
Go
288 lines
12 KiB
Go
// Copyright 2018 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Package cpu implements processor feature detection for
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// various CPU architectures.
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package cpu
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import (
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"os"
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"strings"
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)
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// Initialized reports whether the CPU features were initialized.
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//
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// For some GOOS/GOARCH combinations initialization of the CPU features depends
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// on reading an operating specific file, e.g. /proc/self/auxv on linux/arm
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// Initialized will report false if reading the file fails.
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var Initialized bool
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// CacheLinePad is used to pad structs to avoid false sharing.
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type CacheLinePad struct{ _ [cacheLineSize]byte }
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// X86 contains the supported CPU features of the
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// current X86/AMD64 platform. If the current platform
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// is not X86/AMD64 then all feature flags are false.
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//
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// X86 is padded to avoid false sharing. Further the HasAVX
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// and HasAVX2 are only set if the OS supports XMM and YMM
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// registers in addition to the CPUID feature bit being set.
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var X86 struct {
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_ CacheLinePad
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HasAES bool // AES hardware implementation (AES NI)
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HasADX bool // Multi-precision add-carry instruction extensions
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HasAVX bool // Advanced vector extension
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HasAVX2 bool // Advanced vector extension 2
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HasAVX512 bool // Advanced vector extension 512
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HasAVX512F bool // Advanced vector extension 512 Foundation Instructions
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HasAVX512CD bool // Advanced vector extension 512 Conflict Detection Instructions
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HasAVX512ER bool // Advanced vector extension 512 Exponential and Reciprocal Instructions
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HasAVX512PF bool // Advanced vector extension 512 Prefetch Instructions Instructions
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HasAVX512VL bool // Advanced vector extension 512 Vector Length Extensions
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HasAVX512BW bool // Advanced vector extension 512 Byte and Word Instructions
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HasAVX512DQ bool // Advanced vector extension 512 Doubleword and Quadword Instructions
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HasAVX512IFMA bool // Advanced vector extension 512 Integer Fused Multiply Add
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HasAVX512VBMI bool // Advanced vector extension 512 Vector Byte Manipulation Instructions
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HasAVX5124VNNIW bool // Advanced vector extension 512 Vector Neural Network Instructions Word variable precision
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HasAVX5124FMAPS bool // Advanced vector extension 512 Fused Multiply Accumulation Packed Single precision
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HasAVX512VPOPCNTDQ bool // Advanced vector extension 512 Double and quad word population count instructions
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HasAVX512VPCLMULQDQ bool // Advanced vector extension 512 Vector carry-less multiply operations
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HasAVX512VNNI bool // Advanced vector extension 512 Vector Neural Network Instructions
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HasAVX512GFNI bool // Advanced vector extension 512 Galois field New Instructions
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HasAVX512VAES bool // Advanced vector extension 512 Vector AES instructions
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HasAVX512VBMI2 bool // Advanced vector extension 512 Vector Byte Manipulation Instructions 2
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HasAVX512BITALG bool // Advanced vector extension 512 Bit Algorithms
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HasAVX512BF16 bool // Advanced vector extension 512 BFloat16 Instructions
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HasBMI1 bool // Bit manipulation instruction set 1
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HasBMI2 bool // Bit manipulation instruction set 2
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HasCX16 bool // Compare and exchange 16 Bytes
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HasERMS bool // Enhanced REP for MOVSB and STOSB
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HasFMA bool // Fused-multiply-add instructions
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HasOSXSAVE bool // OS supports XSAVE/XRESTOR for saving/restoring XMM registers.
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HasPCLMULQDQ bool // PCLMULQDQ instruction - most often used for AES-GCM
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HasPOPCNT bool // Hamming weight instruction POPCNT.
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HasRDRAND bool // RDRAND instruction (on-chip random number generator)
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HasRDSEED bool // RDSEED instruction (on-chip random number generator)
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HasSSE2 bool // Streaming SIMD extension 2 (always available on amd64)
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HasSSE3 bool // Streaming SIMD extension 3
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HasSSSE3 bool // Supplemental streaming SIMD extension 3
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HasSSE41 bool // Streaming SIMD extension 4 and 4.1
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HasSSE42 bool // Streaming SIMD extension 4 and 4.2
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_ CacheLinePad
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}
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// ARM64 contains the supported CPU features of the
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// current ARMv8(aarch64) platform. If the current platform
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// is not arm64 then all feature flags are false.
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var ARM64 struct {
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_ CacheLinePad
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HasFP bool // Floating-point instruction set (always available)
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HasASIMD bool // Advanced SIMD (always available)
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HasEVTSTRM bool // Event stream support
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HasAES bool // AES hardware implementation
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HasPMULL bool // Polynomial multiplication instruction set
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HasSHA1 bool // SHA1 hardware implementation
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HasSHA2 bool // SHA2 hardware implementation
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HasCRC32 bool // CRC32 hardware implementation
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HasATOMICS bool // Atomic memory operation instruction set
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HasFPHP bool // Half precision floating-point instruction set
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HasASIMDHP bool // Advanced SIMD half precision instruction set
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HasCPUID bool // CPUID identification scheme registers
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HasASIMDRDM bool // Rounding double multiply add/subtract instruction set
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HasJSCVT bool // Javascript conversion from floating-point to integer
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HasFCMA bool // Floating-point multiplication and addition of complex numbers
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HasLRCPC bool // Release Consistent processor consistent support
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HasDCPOP bool // Persistent memory support
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HasSHA3 bool // SHA3 hardware implementation
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HasSM3 bool // SM3 hardware implementation
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HasSM4 bool // SM4 hardware implementation
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HasASIMDDP bool // Advanced SIMD double precision instruction set
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HasSHA512 bool // SHA512 hardware implementation
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HasSVE bool // Scalable Vector Extensions
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HasASIMDFHM bool // Advanced SIMD multiplication FP16 to FP32
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_ CacheLinePad
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}
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// ARM contains the supported CPU features of the current ARM (32-bit) platform.
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// All feature flags are false if:
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// 1. the current platform is not arm, or
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// 2. the current operating system is not Linux.
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var ARM struct {
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_ CacheLinePad
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HasSWP bool // SWP instruction support
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HasHALF bool // Half-word load and store support
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HasTHUMB bool // ARM Thumb instruction set
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Has26BIT bool // Address space limited to 26-bits
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HasFASTMUL bool // 32-bit operand, 64-bit result multiplication support
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HasFPA bool // Floating point arithmetic support
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HasVFP bool // Vector floating point support
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HasEDSP bool // DSP Extensions support
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HasJAVA bool // Java instruction set
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HasIWMMXT bool // Intel Wireless MMX technology support
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HasCRUNCH bool // MaverickCrunch context switching and handling
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HasTHUMBEE bool // Thumb EE instruction set
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HasNEON bool // NEON instruction set
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HasVFPv3 bool // Vector floating point version 3 support
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HasVFPv3D16 bool // Vector floating point version 3 D8-D15
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HasTLS bool // Thread local storage support
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HasVFPv4 bool // Vector floating point version 4 support
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HasIDIVA bool // Integer divide instruction support in ARM mode
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HasIDIVT bool // Integer divide instruction support in Thumb mode
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HasVFPD32 bool // Vector floating point version 3 D15-D31
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HasLPAE bool // Large Physical Address Extensions
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HasEVTSTRM bool // Event stream support
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HasAES bool // AES hardware implementation
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HasPMULL bool // Polynomial multiplication instruction set
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HasSHA1 bool // SHA1 hardware implementation
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HasSHA2 bool // SHA2 hardware implementation
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HasCRC32 bool // CRC32 hardware implementation
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_ CacheLinePad
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}
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// MIPS64X contains the supported CPU features of the current mips64/mips64le
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// platforms. If the current platform is not mips64/mips64le or the current
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// operating system is not Linux then all feature flags are false.
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var MIPS64X struct {
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_ CacheLinePad
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HasMSA bool // MIPS SIMD architecture
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_ CacheLinePad
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}
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// PPC64 contains the supported CPU features of the current ppc64/ppc64le platforms.
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// If the current platform is not ppc64/ppc64le then all feature flags are false.
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//
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// For ppc64/ppc64le, it is safe to check only for ISA level starting on ISA v3.00,
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// since there are no optional categories. There are some exceptions that also
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// require kernel support to work (DARN, SCV), so there are feature bits for
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// those as well. The struct is padded to avoid false sharing.
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var PPC64 struct {
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_ CacheLinePad
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HasDARN bool // Hardware random number generator (requires kernel enablement)
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HasSCV bool // Syscall vectored (requires kernel enablement)
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IsPOWER8 bool // ISA v2.07 (POWER8)
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IsPOWER9 bool // ISA v3.00 (POWER9), implies IsPOWER8
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_ CacheLinePad
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}
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// S390X contains the supported CPU features of the current IBM Z
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// (s390x) platform. If the current platform is not IBM Z then all
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// feature flags are false.
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//
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// S390X is padded to avoid false sharing. Further HasVX is only set
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// if the OS supports vector registers in addition to the STFLE
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// feature bit being set.
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var S390X struct {
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_ CacheLinePad
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HasZARCH bool // z/Architecture mode is active [mandatory]
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HasSTFLE bool // store facility list extended
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HasLDISP bool // long (20-bit) displacements
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HasEIMM bool // 32-bit immediates
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HasDFP bool // decimal floating point
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HasETF3EH bool // ETF-3 enhanced
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HasMSA bool // message security assist (CPACF)
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HasAES bool // KM-AES{128,192,256} functions
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HasAESCBC bool // KMC-AES{128,192,256} functions
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HasAESCTR bool // KMCTR-AES{128,192,256} functions
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HasAESGCM bool // KMA-GCM-AES{128,192,256} functions
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HasGHASH bool // KIMD-GHASH function
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HasSHA1 bool // K{I,L}MD-SHA-1 functions
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HasSHA256 bool // K{I,L}MD-SHA-256 functions
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HasSHA512 bool // K{I,L}MD-SHA-512 functions
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HasSHA3 bool // K{I,L}MD-SHA3-{224,256,384,512} and K{I,L}MD-SHAKE-{128,256} functions
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HasVX bool // vector facility
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HasVXE bool // vector-enhancements facility 1
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_ CacheLinePad
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}
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func init() {
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archInit()
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initOptions()
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processOptions()
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}
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// options contains the cpu debug options that can be used in GODEBUG.
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// Options are arch dependent and are added by the arch specific initOptions functions.
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// Features that are mandatory for the specific GOARCH should have the Required field set
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// (e.g. SSE2 on amd64).
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var options []option
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// Option names should be lower case. e.g. avx instead of AVX.
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type option struct {
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Name string
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Feature *bool
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Specified bool // whether feature value was specified in GODEBUG
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Enable bool // whether feature should be enabled
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Required bool // whether feature is mandatory and can not be disabled
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}
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func processOptions() {
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env := os.Getenv("GODEBUG")
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field:
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for env != "" {
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field := ""
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i := strings.IndexByte(env, ',')
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if i < 0 {
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field, env = env, ""
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} else {
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field, env = env[:i], env[i+1:]
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}
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if len(field) < 4 || field[:4] != "cpu." {
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continue
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}
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i = strings.IndexByte(field, '=')
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if i < 0 {
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print("GODEBUG sys/cpu: no value specified for \"", field, "\"\n")
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continue
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}
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key, value := field[4:i], field[i+1:] // e.g. "SSE2", "on"
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var enable bool
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switch value {
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case "on":
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enable = true
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case "off":
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enable = false
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default:
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print("GODEBUG sys/cpu: value \"", value, "\" not supported for cpu option \"", key, "\"\n")
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continue field
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}
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if key == "all" {
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for i := range options {
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options[i].Specified = true
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options[i].Enable = enable || options[i].Required
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}
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continue field
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}
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for i := range options {
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if options[i].Name == key {
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options[i].Specified = true
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options[i].Enable = enable
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continue field
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}
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}
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print("GODEBUG sys/cpu: unknown cpu feature \"", key, "\"\n")
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}
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for _, o := range options {
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if !o.Specified {
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continue
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}
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if o.Enable && !*o.Feature {
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print("GODEBUG sys/cpu: can not enable \"", o.Name, "\", missing CPU support\n")
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continue
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}
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if !o.Enable && o.Required {
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print("GODEBUG sys/cpu: can not disable \"", o.Name, "\", required CPU feature\n")
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continue
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}
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*o.Feature = o.Enable
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}
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}
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