1 files changed, 62 insertions, 0 deletions
diff --git a/src/runtime/hash32.go b/src/runtime/hash32.go
new file mode 100644
index 0000000..0616c7d
--- /dev/null
+++ b/src/runtime/hash32.go
@@ -0,0 +1,62 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Hashing algorithm inspired by
+// wyhash: https://github.com/wangyi-fudan/wyhash/blob/ceb019b530e2c1c14d70b79bfa2bc49de7d95bc1/Modern%20Non-Cryptographic%20Hash%20Function%20and%20Pseudorandom%20Number%20Generator.pdf
+
+//go:build 386 || arm || mips || mipsle
+
+package runtime
+
+import "unsafe"
+
+func memhash32Fallback(p unsafe.Pointer, seed uintptr) uintptr {
+	a, b := mix32(uint32(seed), uint32(4^hashkey[0]))
+	t := readUnaligned32(p)
+	a ^= t
+	b ^= t
+	a, b = mix32(a, b)
+	a, b = mix32(a, b)
+	return uintptr(a ^ b)
+}
+
+func memhash64Fallback(p unsafe.Pointer, seed uintptr) uintptr {
+	a, b := mix32(uint32(seed), uint32(8^hashkey[0]))
+	a ^= readUnaligned32(p)
+	b ^= readUnaligned32(add(p, 4))
+	a, b = mix32(a, b)
+	a, b = mix32(a, b)
+	return uintptr(a ^ b)
+}
+
+func memhashFallback(p unsafe.Pointer, seed, s uintptr) uintptr {
+
+	a, b := mix32(uint32(seed), uint32(s^hashkey[0]))
+	if s == 0 {
+		return uintptr(a ^ b)
+	}
+	for ; s > 8; s -= 8 {
+		a ^= readUnaligned32(p)
+		b ^= readUnaligned32(add(p, 4))
+		a, b = mix32(a, b)
+		p = add(p, 8)
+	}
+	if s >= 4 {
+		a ^= readUnaligned32(p)
+		b ^= readUnaligned32(add(p, s-4))
+	} else {
+		t := uint32(*(*byte)(p))
+		t |= uint32(*(*byte)(add(p, s>>1))) << 8
+		t |= uint32(*(*byte)(add(p, s-1))) << 16
+		b ^= t
+	}
+	a, b = mix32(a, b)
+	a, b = mix32(a, b)
+	return uintptr(a ^ b)
+}
+
+func mix32(a, b uint32) (uint32, uint32) {
+	c := uint64(a^uint32(hashkey[1])) * uint64(b^uint32(hashkey[2]))
+	return uint32(c), uint32(c >> 32)
+}