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#ifdef PIC
24# define MO(op) op##@GOTOFF(%edx)
25#else
26# define MO(op) op
27#endif
28
29/*
30 * Use the fyl2xp1 function when the argument is in the range -0.29 to 0.29,
31 * otherwise fyl2x with the needed extra computation.
32 */
33	.text
34ENTRY(__log1pl)
35	fldln2
36
37	fldt	4(%esp)
38
39#ifdef PIC
40	LOAD_PIC_REG (dx)
41#endif
42
43	fxam
44	fnstsw
45	fld	%st
46	sahf
47	jc	3f		// in case x is NaN or �Inf
484:
49	fabs
50	fldt	MO(limit)
51	fcompp
52	fnstsw
53	sahf
54	jnc	2f
55
56	movzwl	4+8(%esp), %eax
57	xorb	$0x80, %ah
58	cmpl	$0xc040, %eax
59	jae	5f
60
61	faddl	MO(one)
625:	fyl2x
63	ret
64
652:	fyl2xp1
66	ret
67
683:	jp	4b		// in case x is �Inf
69	fstp	%st(1)
70	fstp	%st(1)
71	fadd	%st(0)
72	ret
73
74END (__log1pl)
75