xref: /illumos-gate/usr/src/lib/libm/i386/src/log.S (revision 55fea89dcaa64928bed4327112404dcb3e07b79f)
1*5d9d9091SRichard Lowe/*
2*5d9d9091SRichard Lowe * CDDL HEADER START
3*5d9d9091SRichard Lowe *
4*5d9d9091SRichard Lowe * The contents of this file are subject to the terms of the
5*5d9d9091SRichard Lowe * Common Development and Distribution License (the "License").
6*5d9d9091SRichard Lowe * You may not use this file except in compliance with the License.
7*5d9d9091SRichard Lowe *
8*5d9d9091SRichard Lowe * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9*5d9d9091SRichard Lowe * or http://www.opensolaris.org/os/licensing.
10*5d9d9091SRichard Lowe * See the License for the specific language governing permissions
11*5d9d9091SRichard Lowe * and limitations under the License.
12*5d9d9091SRichard Lowe *
13*5d9d9091SRichard Lowe * When distributing Covered Code, include this CDDL HEADER in each
14*5d9d9091SRichard Lowe * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15*5d9d9091SRichard Lowe * If applicable, add the following below this CDDL HEADER, with the
16*5d9d9091SRichard Lowe * fields enclosed by brackets "[]" replaced with your own identifying
17*5d9d9091SRichard Lowe * information: Portions Copyright [yyyy] [name of copyright owner]
18*5d9d9091SRichard Lowe *
19*5d9d9091SRichard Lowe * CDDL HEADER END
20*5d9d9091SRichard Lowe */
21*5d9d9091SRichard Lowe/*
22*5d9d9091SRichard Lowe * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
23*5d9d9091SRichard Lowe */
24*5d9d9091SRichard Lowe/*
25*5d9d9091SRichard Lowe * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
26*5d9d9091SRichard Lowe * Use is subject to license terms.
27*5d9d9091SRichard Lowe */
28*5d9d9091SRichard Lowe
29*5d9d9091SRichard Lowe	.file "log.s"
30*5d9d9091SRichard Lowe
31*5d9d9091SRichard Lowe#include "libm.h"
32*5d9d9091SRichard LoweLIBM_ANSI_PRAGMA_WEAK(log,function)
33*5d9d9091SRichard Lowe#include "libm_protos.h"
34*5d9d9091SRichard Lowe
35*5d9d9091SRichard Lowe	ENTRY(log)
36*5d9d9091SRichard Lowe	fldln2				/ loge(2)
37*5d9d9091SRichard Lowe	movl	8(%esp),%eax		/ eax <-- hi_32(x)
38*5d9d9091SRichard Lowe	testl	$0x80000000,%eax
39*5d9d9091SRichard Lowe	jnz	.maybe_0_or_less
40*5d9d9091SRichard Lowe	testl	$0x7fffffff,%eax
41*5d9d9091SRichard Lowe	jz	.maybe_0
42*5d9d9091SRichard Lowe	fldl	4(%esp)			/ arg, loge(2)
43*5d9d9091SRichard Lowe	fyl2x				/ loge(2)*log2(arg); ln(arg)
44*5d9d9091SRichard Lowe	ret
45*5d9d9091SRichard Lowe
46*5d9d9091SRichard Lowe.maybe_0:
47*5d9d9091SRichard Lowe	movl	4(%esp),%ecx		/ ecx <-- lo_32(x)
48*5d9d9091SRichard Lowe	cmpl	$0,%ecx
49*5d9d9091SRichard Lowe	je	.zero			/ no branch if x is +denormal
50*5d9d9091SRichard Lowe.neg_nan_reentry:
51*5d9d9091SRichard Lowe	fldl	4(%esp)			/ arg, loge(2)
52*5d9d9091SRichard Lowe	fyl2x				/ loge(2)*log2(arg); ln(arg)
53*5d9d9091SRichard Lowe	ret
54*5d9d9091SRichard Lowe
55*5d9d9091SRichard Lowe.zero_or_less:
56*5d9d9091SRichard Lowe	/ x =< 0
57*5d9d9091SRichard Lowe	testl	$0x7fffffff,%eax
58*5d9d9091SRichard Lowe	jnz	.less_than_0
59*5d9d9091SRichard Lowe	movl	4(%esp),%ecx		/ ecx <-- lo_32(x)
60*5d9d9091SRichard Lowe	cmpl	$0,%ecx
61*5d9d9091SRichard Lowe	jne	.less_than_0		/ branch if x is -denormal
62*5d9d9091SRichard Lowe.zero:
63*5d9d9091SRichard Lowe	/ x = +/-0
64*5d9d9091SRichard Lowe	pushl	%ebp
65*5d9d9091SRichard Lowe	movl	%esp,%ebp
66*5d9d9091SRichard Lowe	PIC_SETUP(1)
67*5d9d9091SRichard Lowe	pushl	$16
68*5d9d9091SRichard Lowe	jmp	.merge
69*5d9d9091SRichard Lowe
70*5d9d9091SRichard Lowe.maybe_0_or_less:
71*5d9d9091SRichard Lowe	cmpl	$0xfff00000,%eax	/ -INF below hi_32(x)?
72*5d9d9091SRichard Lowe	ja	.neg_nan_reentry
73*5d9d9091SRichard Lowe	jb	.zero_or_less
74*5d9d9091SRichard Lowe	movl	4(%esp),%ecx		/ ecx <-- lo_32(x)
75*5d9d9091SRichard Lowe	cmpl	$0,%ecx			/ is x NaN or -INF?
76*5d9d9091SRichard Lowe	jne	.neg_nan_reentry	/ branch if x is NaN with signbit = 1
77*5d9d9091SRichard Lowe	/ x = -INF
78*5d9d9091SRichard Lowe.less_than_0:
79*5d9d9091SRichard Lowe	pushl	%ebp
80*5d9d9091SRichard Lowe	movl	%esp,%ebp
81*5d9d9091SRichard Lowe	PIC_SETUP(2)
82*5d9d9091SRichard Lowe	pushl	$17
83*5d9d9091SRichard Lowe.merge:
84*5d9d9091SRichard Lowe	fstp	%st(0)			/ stack empty
85*5d9d9091SRichard Lowe	pushl	12(%ebp)
86*5d9d9091SRichard Lowe	pushl	8(%ebp)
87*5d9d9091SRichard Lowe	pushl	12(%ebp)
88*5d9d9091SRichard Lowe	pushl	8(%ebp)
89*5d9d9091SRichard Lowe	call	PIC_F(_SVID_libm_err)
90*5d9d9091SRichard Lowe	addl	$20,%esp
91*5d9d9091SRichard Lowe	PIC_WRAPUP
92*5d9d9091SRichard Lowe	leave
93*5d9d9091SRichard Lowe	ret
94*5d9d9091SRichard Lowe	.align	4
95*5d9d9091SRichard Lowe	SET_SIZE(log)
96