39 lines
1.2 KiB
Go
39 lines
1.2 KiB
Go
// Copyright 2014 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 runtime
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import _ "unsafe"
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//go:linkname fastrand C.rand
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func fastrand() uint32
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/* TODO(xsw):
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func fastrand() uint32 {
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mp := getg().m
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// Implement wyrand: https://github.com/wangyi-fudan/wyhash
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// Only the platform that math.Mul64 can be lowered
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// by the compiler should be in this list.
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if goarch.IsAmd64|goarch.IsArm64|goarch.IsPpc64|
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goarch.IsPpc64le|goarch.IsMips64|goarch.IsMips64le|
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goarch.IsS390x|goarch.IsRiscv64|goarch.IsLoong64 == 1 {
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mp.fastrand += 0xa0761d6478bd642f
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hi, lo := math.Mul64(mp.fastrand, mp.fastrand^0xe7037ed1a0b428db)
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return uint32(hi ^ lo)
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}
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// Implement xorshift64+: 2 32-bit xorshift sequences added together.
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// Shift triplet [17,7,16] was calculated as indicated in Marsaglia's
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// Xorshift paper: https://www.jstatsoft.org/article/view/v008i14/xorshift.pdf
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// This generator passes the SmallCrush suite, part of TestU01 framework:
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// http://simul.iro.umontreal.ca/testu01/tu01.html
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t := (*[2]uint32)(unsafe.Pointer(&mp.fastrand))
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s1, s0 := t[0], t[1]
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s1 ^= s1 << 17
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s1 = s1 ^ s0 ^ s1>>7 ^ s0>>16
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t[0], t[1] = s0, s1
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return s0 + s1
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}
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*/
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