shithub: snippets

ref: 930433a467b174dd86081fbec4079805f31cb388
dir: /c_builtins_amd64.s/

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TEXT __builtin_ctz(SB),1,$0
	BSFL RARG, AX
	RET

TEXT __builtin_clz(SB),1,$0
	BSRL RARG, AX
	XORL $31, AX
	RET

TEXT __builtin_clzll(SB),1,$0
	BSRQ RARG, AX
	XORL $63, AX
	RET