diff options
Diffstat (limited to 'src/runtime/stubs.go')
| -rw-r--r-- | src/runtime/stubs.go | 43 |
1 files changed, 41 insertions, 2 deletions
diff --git a/src/runtime/stubs.go b/src/runtime/stubs.go index 8c4ab3ed4e..929f8fadca 100644 --- a/src/runtime/stubs.go +++ b/src/runtime/stubs.go @@ -157,11 +157,50 @@ func fastrandn(n uint32) uint32 { return uint32(uint64(fastrand()) * uint64(n) >> 32) } +func fastrand64() uint64 { + mp := getg().m + // Implement wyrand: https://github.com/wangyi-fudan/wyhash + // Only the platform that math.Mul64 can be lowered + // by the compiler should be in this list. + if goarch.IsAmd64|goarch.IsArm64|goarch.IsPpc64| + goarch.IsPpc64le|goarch.IsMips64|goarch.IsMips64le| + goarch.IsS390x|goarch.IsRiscv64 == 1 { + mp.fastrand += 0xa0761d6478bd642f + hi, lo := math.Mul64(mp.fastrand, mp.fastrand^0xe7037ed1a0b428db) + return hi ^ lo + } + + // Implement xorshift64+: 2 32-bit xorshift sequences added together. + // Xorshift paper: https://www.jstatsoft.org/article/view/v008i14/xorshift.pdf + // This generator passes the SmallCrush suite, part of TestU01 framework: + // http://simul.iro.umontreal.ca/testu01/tu01.html + t := (*[2]uint32)(unsafe.Pointer(&mp.fastrand)) + s1, s0 := t[0], t[1] + s1 ^= s1 << 17 + s1 = s1 ^ s0 ^ s1>>7 ^ s0>>16 + r := uint64(s0 + s1) + + s0, s1 = s1, s0 + s1 ^= s1 << 17 + s1 = s1 ^ s0 ^ s1>>7 ^ s0>>16 + r += uint64(s0+s1) << 32 + + t[0], t[1] = s0, s1 + return r +} + +func fastrandu() uint { + if goarch.PtrSize == 4 { + return uint(fastrand()) + } + return uint(fastrand64()) +} + //go:linkname sync_fastrandn sync.fastrandn func sync_fastrandn(n uint32) uint32 { return fastrandn(n) } -//go:linkname net_fastrand net.fastrand -func net_fastrand() uint32 { return fastrand() } +//go:linkname net_fastrandu net.fastrandu +func net_fastrandu() uint { return fastrandu() } //go:linkname os_fastrand os.fastrand func os_fastrand() uint32 { return fastrand() } |