1/*
2 * Public domain.
3 *
4 */
5
6#include <machine/asm.h>
7
8RCSID("$NetBSD: s_log1p.S,v 1.7 1995/05/09 00:10:58 jtc Exp $")
9
10	.section .rodata
11
12	.align ALIGNARG(4)
13	/* The fyl2xp1 can only be used for values in
14		-1 + sqrt(2) / 2 <= x <= 1 - sqrt(2) / 2
15	   0.29 is a safe value.
16	*/
17limit:	.tfloat 0.29
18	/* Please note:	 we use a double value here.  Since 1.0 has
19	   an exact representation this does not effect the accuracy
20	   but it helps to optimize the code.  */
21one:	.double 1.0
22
23/*
24 * Use the fyl2xp1 function when the argument is in the range -0.29 to 0.29,
25 * otherwise fyl2x with the needed extra computation.
26 */
27#ifdef PIC
28#define MO(op) op##(%rip)
29#else
30#define MO(op) op
31#endif
32
33	.text
34ENTRY(__log1pl)
35	fldln2
36
37	fldt	8(%rsp)
38
39	fxam
40	fnstsw
41	fld	%st
42	testb	$1, %ah
43	jnz	3f		// in case x is NaN or �Inf
444:
45	fabs
46	fldt	MO(limit)
47	fcompp
48	fnstsw
49	andb	$1,%ah
50	jz	2f
51
52	movzwl	8+8(%rsp), %eax
53	xorb	$0x80, %ah
54	cmpl	$0xc040, %eax
55	jae	5f
56
57	faddl	MO(one)
585:	fyl2x
59	ret
60
612:	fyl2xp1
62	ret
63
643:	testb	$4, %ah
65	jnz	4b		// in case x is �Inf
66	fstp	%st(1)
67	fstp	%st(1)
68	fadd	%st(0)
69	ret
70
71END (__log1pl)
72