log.s

来自「著名操作系统Plan 9的第三版的部分核心源代码。现在很难找到了。Plan 9是」· S 代码 · 共 32 行

TEXT	log(SB), $0
	FMOVD	$0.69314718055994530941, F0
	FMOVD	a+0(FP), F0

	FTST
	WAIT
	FSTSW	AX
	SAHF
	JLO	bad

	FYL2X
	RET

TEXT	log10(SB), $0
	FMOVD	$0.30102999566398119521, F0
	FMOVD	a+0(FP), F0

	FTST
	WAIT
	FSTSW	AX
	SAHF
	JLO	bad

	FYL2X
	RET

bad:
	FMOVDP	F0, F0
	FMOVDP	F0, F0
	CALL	NaN(SB)
	RET