2018-12-13 00:18:44 -08:00
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// +build ignore
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package main
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import (
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. "github.com/mmcloughlin/avo/build"
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"github.com/mmcloughlin/avo/operand"
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"github.com/mmcloughlin/avo/reg"
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)
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const (
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OffsetBasis = 0xcbf29ce484222325
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Prime = 0x100000001b3
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)
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func main() {
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TEXT("Hash64", "func(data []byte) uint64")
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2018-12-27 23:09:44 -08:00
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Doc("Hash64 computes the FNV-1a hash of data.")
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2018-12-13 00:18:44 -08:00
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ptr := Load(Param("data").Base(), GP64v())
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n := Load(Param("data").Len(), GP64v())
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h := reg.RAX
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MOVQ(operand.Imm(OffsetBasis), h)
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p := GP64v()
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MOVQ(operand.Imm(Prime), p)
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LABEL("loop")
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CMPQ(n, operand.Imm(0))
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JE(operand.LabelRef("done"))
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b := GP64v()
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MOVBQZX(operand.Mem{Base: ptr}, b)
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XORQ(b, h)
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MULQ(p)
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INCQ(ptr)
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DECQ(n)
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JMP(operand.LabelRef("loop"))
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LABEL("done")
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Store(h, ReturnIndex(0))
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RET()
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Generate()
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}
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