602bb5197c
The Context.Label method and LABEL global function did not agree. Also breaks the convention I'd like to set that capitalized functions must agree with existing Go assembly syntax. To help avoid a conflict with `avo.Label`, attributes were moved to their own package. Fixes #35
40 lines
717 B
Markdown
40 lines
717 B
Markdown
# fnv1a
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[FNV-1a](https://en.wikipedia.org/wiki/Fowler%E2%80%93Noll%E2%80%93Vo_hash_function#FNV-1a_hash) in `avo`.
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[embedmd]:# (asm.go /const/ $)
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```go
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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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Doc("Hash64 computes the FNV-1a hash of data.")
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ptr := Load(Param("data").Base(), GP64())
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n := Load(Param("data").Len(), GP64())
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h := RAX
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MOVQ(Imm(OffsetBasis), h)
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p := GP64()
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MOVQ(Imm(Prime), p)
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Label("loop")
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CMPQ(n, Imm(0))
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JE(LabelRef("done"))
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b := GP64()
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MOVBQZX(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(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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```
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