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65 lines
1.4 KiB
65 lines
1.4 KiB
5 years ago
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//
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// hamming distance calculations in Go
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//
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// https://github.com/steakknife/hamming
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//
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// Copyright © 2014, 2015, 2016 Barry Allard
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//
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// MIT license
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//
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#include "textflag.h"
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TEXT ·CountBitsInt8PopCnt(SB),NOSPLIT,$0
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JMP ·CountBitsBytePopCnt(SB)
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TEXT ·CountBitsInt16PopCnt(SB),NOSPLIT,$0
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JMP ·CountBitsUint16PopCnt(SB)
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TEXT ·CountBitsInt32PopCnt(SB),NOSPLIT,$0
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JMP ·CountBitsUint32PopCnt(SB)
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TEXT ·CountBitsInt64PopCnt(SB),NOSPLIT,$0
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JMP ·CountBitsUint64PopCnt(SB)
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TEXT ·CountBitsBytePopCnt(SB),NOSPLIT,$0
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JMP ·CountBitsUint8PopCnt(SB)
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TEXT ·CountBitsRunePopCnt(SB),NOSPLIT,$0
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JMP ·CountBitsUint32PopCnt(SB)
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TEXT ·CountBitsUint8PopCnt(SB),NOSPLIT,$0
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XORQ AX, AX
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MOVB x+0(FP), AX
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POPCNTQ AX, AX
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MOVQ AX, ret+8(FP)
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RET
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TEXT ·CountBitsUint16PopCnt(SB),NOSPLIT,$0
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XORQ AX, AX
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MOVW x+0(FP), AX
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POPCNTQ AX, AX
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MOVQ AX, ret+8(FP)
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RET
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TEXT ·CountBitsUint32PopCnt(SB),NOSPLIT,$0
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XORQ AX, AX
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MOVL x+0(FP), AX
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POPCNTQ AX, AX
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MOVQ AX, ret+8(FP)
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RET
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TEXT ·CountBitsUint64PopCnt(SB),NOSPLIT,$0
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POPCNTQ x+0(FP), AX
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MOVQ AX, ret+8(FP)
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RET
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// func hasPopCnt() (ret bool)
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TEXT ·HasPopCnt(SB),NOSPLIT,$0
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MOVL $1, AX
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CPUID
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SHRL $23, CX // bit 23: Advanced Bit Manipulation Bit (ABM) -> POPCNTQ
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ANDL $1, CX
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MOVB CX, ret+0(FP)
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RET
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