package cpu

Import Path
	internal/cpu (on go.dev)

Dependency Relation
	imports 0 packages, and imported by 11 packages

Involved Source Files

	  d cpu.go
		Package cpu implements processor feature detection
		used by the Go standard library.

	    cpu_x86.go
	    cpu.s
	    cpu_x86.s
Package-Level Type Names (total 2, in which 1 is exported)

	/* sort exporteds by: alphabet | popularity */
	 type CacheLinePad (struct)
		CacheLinePad is used to pad structs to avoid false sharing.

	/* one unexported ... *//* one unexported: */
	 type option (struct)
		Option names should be lower case. e.g. avx instead of AVX.

		Fields (total 4, all are exported)
			Enable bool
				// whether feature should be enabled

			Feature *bool
			Name string
			Specified bool
				// whether feature value was specified in GODEBUG



Package-Level Functions (total 10, in which 2 are exported)

	 func Initialize(env string)
		Initialize examines the processor and sets the relevant variables above.
		This is called by the runtime package early in program initialization,
		before normal init functions are run. env is set by runtime if the OS supports
		cpu feature options in GODEBUG.

	 func Name() string
		Name returns the CPU name given by the vendor.
		If the CPU name can not be determined an
		empty string is returned.

	/* 8 unexporteds ... *//* 8 unexporteds: */
	 func appendBytes(b []byte, args ...uint32) []byte
	 func cpuid(eaxArg, ecxArg uint32) (eax, ebx, ecx, edx uint32)
		cpuid is implemented in cpu_x86.s.

	 func doinit()
	 func getGOAMD64level() int32
		getGOAMD64level is implemented in cpu_x86.s. Returns number in [1,4].

	 func indexByte(s string, c byte) int
		indexByte returns the index of the first instance of c in s,
		or -1 if c is not present in s.

	 func isSet(hwc uint32, value uint32) bool
	 func processOptions(env string)
		processOptions enables or disables CPU feature values based on the parsed env string.
		The env string is expected to be of the form cpu.feature1=value1,cpu.feature2=value2...
		where feature names is one of the architecture specific list stored in the
		cpu packages options variable and values are either 'on' or 'off'.
		If env contains cpu.all=off then all cpu features referenced through the options
		variable are disabled. Other feature names and values result in warning messages.

	 func xgetbv() (eax, edx uint32)
		xgetbv with ecx = 0 is implemented in cpu_x86.s.


Package-Level Variables (total 10, in which 8 are exported)

	  var ARM struct{_ CacheLinePad; HasVFPv4 bool; HasIDIVA bool; _ CacheLinePad}
		The booleans in ARM contain the correspondingly named cpu feature bit.
		The struct is padded to avoid false sharing.

	  var ARM64 struct{_ CacheLinePad; HasAES bool; HasPMULL bool; HasSHA1 bool; HasSHA2 bool; HasSHA512 bool; HasCRC32 bool; HasATOMICS bool; HasCPUID bool; IsNeoverse bool; _ CacheLinePad}
		The booleans in ARM64 contain the correspondingly named cpu feature bit.
		The struct is padded to avoid false sharing.

	  var CacheLineSize uintptr
		CacheLineSize is the CPU's assumed cache line size.
		There is currently no runtime detection of the real cache line size
		so we use the constant per GOARCH CacheLinePadSize as an approximation.

	  var DebugOptions bool
		DebugOptions is set to true by the runtime if the OS supports reading
		GODEBUG early in runtime startup.
		This should not be changed after it is initialized.

	  var MIPS64X struct{_ CacheLinePad; HasMSA bool; _ CacheLinePad}
	  var PPC64 struct{_ CacheLinePad; HasDARN bool; HasSCV bool; IsPOWER8 bool; IsPOWER9 bool; IsPOWER10 bool; _ CacheLinePad}
		For ppc64(le), it is safe to check only for ISA level starting on ISA v3.00,
		since there are no optional categories. There are some exceptions that also
		require kernel support to work (darn, scv), so there are feature bits for
		those as well. The minimum processor requirement is POWER8 (ISA 2.07).
		The struct is padded to avoid false sharing.

	  var S390X struct{_ CacheLinePad; HasZARCH bool; HasSTFLE bool; HasLDISP bool; HasEIMM bool; HasDFP bool; HasETF3EH bool; HasMSA bool; HasAES bool; HasAESCBC bool; HasAESCTR bool; HasAESGCM bool; HasGHASH bool; HasSHA1 bool; HasSHA256 bool; HasSHA512 bool; HasSHA3 bool; HasVX bool; HasVXE bool; HasKDSA bool; HasECDSA bool; HasEDDSA bool; _ CacheLinePad}
	  var X86 struct{_ CacheLinePad; HasAES bool; HasADX bool; HasAVX bool; HasAVX2 bool; HasBMI1 bool; HasBMI2 bool; HasERMS bool; HasFMA bool; HasOSXSAVE bool; HasPCLMULQDQ bool; HasPOPCNT bool; HasRDTSCP bool; HasSHA bool; HasSSE3 bool; HasSSSE3 bool; HasSSE41 bool; HasSSE42 bool; _ CacheLinePad}
		The booleans in X86 contain the correspondingly named cpuid feature bit.
		HasAVX and HasAVX2 are only set if the OS does support XMM and YMM registers
		in addition to the cpuid feature bit being set.
		The struct is padded to avoid false sharing.

	/* 2 unexporteds ... *//* 2 unexporteds: */
	  var maxExtendedFunctionInformation uint32
	  var options []option
		options contains the cpu debug options that can be used in GODEBUG.
		Options are arch dependent and are added by the arch specific doinit functions.
		Features that are mandatory for the specific GOARCH should not be added to options
		(e.g. SSE2 on amd64).


Package-Level Constants (total 19, in which 1 is exported)

	const CacheLinePadSize = 64
	/* 18 unexporteds ... *//* 18 unexporteds: */
	const cpuid_ADX = 524288
	const cpuid_AES = 33554432
	const cpuid_AVX = 268435456
	const cpuid_AVX2 = 32
	const cpuid_BMI1 = 8
		ebx bits

	const cpuid_BMI2 = 256
	const cpuid_ERMS = 512
	const cpuid_FMA = 4096
	const cpuid_OSXSAVE = 134217728
	const cpuid_PCLMULQDQ = 2
	const cpuid_POPCNT = 8388608
	const cpuid_RDTSCP = 134217728
		edx bits for CPUID 0x80000001

	const cpuid_SHA = 536870912
	const cpuid_SSE2 = 67108864
		edx bits

	const cpuid_SSE3 = 1
		ecx bits

	const cpuid_SSE41 = 524288
	const cpuid_SSE42 = 1048576
	const cpuid_SSSE3 = 512

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