package sys

import "runtime/internal/sys"

package sys contains system- and configuration- and architecture-specific constants used by the runtime.

Index ¶

• Constants
• func Bswap32(x uint32) uint32
• func Bswap64(x uint64) uint64
• func Ctz32(x uint32) int
• func Ctz64(x uint64) int
• func Ctz8(x uint8) int
• func LeadingZeros64(x uint64) int
• func LeadingZeros8(x uint8) int
• func Len64(x uint64) (n int)
• func Len8(x uint8) int
• func OnesCount64(x uint64) int
• func Prefetch(addr uintptr)
• func PrefetchStreamed(addr uintptr)
• func TrailingZeros64(x uint64) int
• func TrailingZeros8(x uint8) int

Constants ¶

const DefaultPhysPageSize = goarch.DefaultPhysPageSize

DefaultPhysPageSize is the default physical page size.

const Int64Align = goarch.PtrSize

Int64Align is the required alignment for a 64-bit integer (4 on 32-bit systems, 8 on 64-bit).

const MinFrameSize = goarch.MinFrameSize

MinFrameSize is the size of the system-reserved words at the bottom of a frame (just above the architectural stack pointer). It is zero on x86 and PtrSize on most non-x86 (LR-based) systems. On PowerPC it is larger, to cover three more reserved words: the compiler word, the link editor word, and the TOC save word.

const PCQuantum = goarch.PCQuantum

PCQuantum is the minimal unit for a program counter (1 on x86, 4 on most other systems). The various PC tables record PC deltas pre-divided by PCQuantum.

const StackAlign = goarch.StackAlign

StackAlign is the required alignment of the SP register. The stack must be at least word aligned, but some architectures require more.

const StackGuardMultiplier = StackGuardMultiplierDefault*(1-goos.IsAix) + 2*goos.IsAix

AIX requires a larger stack for syscalls.

const StackGuardMultiplierDefault = 1

Functions ¶

func Bswap32 ¶

func Bswap32(x uint32) uint32

Bswap32 returns its input with byte order reversed 0x01020304 -> 0x04030201

func Bswap64 ¶

func Bswap64(x uint64) uint64

Bswap64 returns its input with byte order reversed 0x0102030405060708 -> 0x0807060504030201

func Ctz32 ¶

func Ctz32(x uint32) int

Ctz32 counts trailing (low-order) zeroes, and if all are zero, then 32.

func Ctz64 ¶

func Ctz64(x uint64) int

Ctz64 counts trailing (low-order) zeroes, and if all are zero, then 64.

func Ctz8 ¶

func Ctz8(x uint8) int

Ctz8 returns the number of trailing zero bits in x; the result is 8 for x == 0.

func LeadingZeros64 ¶

func LeadingZeros64(x uint64) int

LeadingZeros64 returns the number of leading zero bits in x; the result is 64 for x == 0.

func LeadingZeros8 ¶

func LeadingZeros8(x uint8) int

LeadingZeros8 returns the number of leading zero bits in x; the result is 8 for x == 0.

func Len64 ¶

func Len64(x uint64) (n int)

len64 returns the minimum number of bits required to represent x; the result is 0 for x == 0.

func Len8 ¶

func Len8(x uint8) int

Len8 returns the minimum number of bits required to represent x; the result is 0 for x == 0.

func OnesCount64 ¶

func OnesCount64(x uint64) int

OnesCount64 returns the number of one bits ("population count") in x.

func Prefetch ¶

func Prefetch(addr uintptr)

Prefetch prefetches data from memory addr to cache

AMD64: Produce PREFETCHT0 instruction

ARM64: Produce PRFM instruction with PLDL1KEEP option

func PrefetchStreamed ¶

func PrefetchStreamed(addr uintptr)

PrefetchStreamed prefetches data from memory addr, with a hint that this data is being streamed. That is, it is likely to be accessed very soon, but only once. If possible, this will avoid polluting the cache.

AMD64: Produce PREFETCHNTA instruction

ARM64: Produce PRFM instruction with PLDL1STRM option

func TrailingZeros64 ¶

func TrailingZeros64(x uint64) int

TrailingZeros64 returns the number of trailing zero bits in x; the result is 64 for x == 0.

func TrailingZeros8 ¶

func TrailingZeros8(x uint8) int

TrailingZeros8 returns the number of trailing zero bits in x; the result is 8 for x == 0.

Source Files ¶

consts.go intrinsics.go intrinsics_common.go sys.go zversion.go