shithub: snippets

ref: f5ad0ff02ba05f2f5e0926b85668968fbebeb721
dir: /c_builtins_amd64.s/

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TEXT __builtin_ctz(SB),1,$0
	BYTE $0x0F; BYTE $0xBC; BYTE $0xC5 /* BSFL RARG, AX */
	RET

TEXT __builtin_clz(SB),1,$0
	BYTE $0x0F; BYTE $0xBD; BYTE $0xC5 /* BSRL RARG, AX */
	XORL $31, AX
	RET

TEXT __builtin_clzll(SB),1,$0
	BYTE $0x48; BYTE $0x0F; BYTE $0xBD; BYTE $0xC5 /* BSRQ RARG, AX */
	XORL $63, AX
	RET