14 lines
245 B
ArmAsm
14 lines
245 B
ArmAsm
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// +build amd64,!appengine
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// func Clz(x uint64) uint64
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TEXT ·Clz(SB),4,$0-16
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BSRQ x+0(FP), AX
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JZ zero
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SUBQ $63, AX
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NEGQ AX
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MOVQ AX, ret+8(FP)
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RET
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zero:
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MOVQ $64, ret+8(FP)
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RET
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