xref: /titanic_44/usr/src/lib/libm/amd64/src/expm1l.s (revision ddc0e0b53c661f6e439e3b7072b3ef353eadb4af)
1*25c28e83SPiotr Jasiukajtis/*
2*25c28e83SPiotr Jasiukajtis * CDDL HEADER START
3*25c28e83SPiotr Jasiukajtis *
4*25c28e83SPiotr Jasiukajtis * The contents of this file are subject to the terms of the
5*25c28e83SPiotr Jasiukajtis * Common Development and Distribution License (the "License").
6*25c28e83SPiotr Jasiukajtis * You may not use this file except in compliance with the License.
7*25c28e83SPiotr Jasiukajtis *
8*25c28e83SPiotr Jasiukajtis * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9*25c28e83SPiotr Jasiukajtis * or http://www.opensolaris.org/os/licensing.
10*25c28e83SPiotr Jasiukajtis * See the License for the specific language governing permissions
11*25c28e83SPiotr Jasiukajtis * and limitations under the License.
12*25c28e83SPiotr Jasiukajtis *
13*25c28e83SPiotr Jasiukajtis * When distributing Covered Code, include this CDDL HEADER in each
14*25c28e83SPiotr Jasiukajtis * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15*25c28e83SPiotr Jasiukajtis * If applicable, add the following below this CDDL HEADER, with the
16*25c28e83SPiotr Jasiukajtis * fields enclosed by brackets "[]" replaced with your own identifying
17*25c28e83SPiotr Jasiukajtis * information: Portions Copyright [yyyy] [name of copyright owner]
18*25c28e83SPiotr Jasiukajtis *
19*25c28e83SPiotr Jasiukajtis * CDDL HEADER END
20*25c28e83SPiotr Jasiukajtis */
21*25c28e83SPiotr Jasiukajtis/*
22*25c28e83SPiotr Jasiukajtis * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
23*25c28e83SPiotr Jasiukajtis */
24*25c28e83SPiotr Jasiukajtis/*
25*25c28e83SPiotr Jasiukajtis * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
26*25c28e83SPiotr Jasiukajtis * Use is subject to license terms.
27*25c28e83SPiotr Jasiukajtis */
28*25c28e83SPiotr Jasiukajtis
29*25c28e83SPiotr Jasiukajtis        .file "expm1l.s"
30*25c28e83SPiotr Jasiukajtis
31*25c28e83SPiotr Jasiukajtis#include "libm.h"
32*25c28e83SPiotr JasiukajtisLIBM_ANSI_PRAGMA_WEAK(expm1l,function)
33*25c28e83SPiotr Jasiukajtis
34*25c28e83SPiotr Jasiukajtis	.data
35*25c28e83SPiotr Jasiukajtis	.align	16
36*25c28e83SPiotr Jasiukajtisln2_hi:	.4byte	0xd1d00000, 0xb17217f7, 0x3ffe, 0x0
37*25c28e83SPiotr Jasiukajtisln2_lo:	.4byte	0x4c67fc0d, 0x8654361c, 0xbfce, 0x0
38*25c28e83SPiotr Jasiukajtis
39*25c28e83SPiotr Jasiukajtis	ENTRY(expm1l)
40*25c28e83SPiotr Jasiukajtis	movl	16(%rsp),%ecx		/ cx <--sign&bexp(x)
41*25c28e83SPiotr Jasiukajtis	movl	%ecx,%eax		/ ax <--sign&bexp(x)
42*25c28e83SPiotr Jasiukajtis	andl	$0x7fff,%ecx		/ ecx <-- zero_xtnd(bexp(x))
43*25c28e83SPiotr Jasiukajtis	cmpl	$0x3ffe,%ecx		/ Is |x| < ln(2)?
44*25c28e83SPiotr Jasiukajtis	jb	.shortcut		/ If so, take a shortcut.
45*25c28e83SPiotr Jasiukajtis	je	.check_tail		/ |x| may be only slightly < ln(2)
46*25c28e83SPiotr Jasiukajtis.general_case:				/ Here, |x| > ln(2) or x is NaN
47*25c28e83SPiotr Jasiukajtis	cmpl	$0x7fff,%ecx		/ bexp(|x|) = bexp(INF)?
48*25c28e83SPiotr Jasiukajtis	je	.not_finite		/ if so, x is not finite
49*25c28e83SPiotr Jasiukajtis	andl	$0xffff,%eax		/ eax <-- sign&bexp(x)
50*25c28e83SPiotr Jasiukajtis	cmpl	$0xc006,%eax		/ x <= -128?
51*25c28e83SPiotr Jasiukajtis	jae	1f			/ if so, simply return -1
52*25c28e83SPiotr Jasiukajtis	cmpl	$0x400d,%ecx		/ |x| < 16384 = 2^14?
53*25c28e83SPiotr Jasiukajtis	jb	.finite_non_special	/ if so, proceed with argument reduction
54*25c28e83SPiotr Jasiukajtis	fldt	8(%rsp)			/ x >= 16384; x
55*25c28e83SPiotr Jasiukajtis	fld1				/ 1, x
56*25c28e83SPiotr Jasiukajtis	fscale				/ +Inf, x
57*25c28e83SPiotr Jasiukajtis	fstp	%st(1)			/ +Inf
58*25c28e83SPiotr Jasiukajtis	ret
59*25c28e83SPiotr Jasiukajtis
60*25c28e83SPiotr Jasiukajtis.finite_non_special:			/ -128 < x < -ln(2) || ln(2) < x < 2^14
61*25c28e83SPiotr Jasiukajtis	fldt	8(%rsp)			/ x
62*25c28e83SPiotr Jasiukajtis	fld	%st(0)			/ x, x
63*25c28e83SPiotr Jasiukajtis	fldl2e				/ log2(e), x, x
64*25c28e83SPiotr Jasiukajtis	fmulp				/ z := x*log2(e), x
65*25c28e83SPiotr Jasiukajtis	frndint				/ [z], x
66*25c28e83SPiotr Jasiukajtis	fst	%st(2)			/ [z], x, [z]
67*25c28e83SPiotr Jasiukajtis	PIC_SETUP(1)
68*25c28e83SPiotr Jasiukajtis	fldt	PIC_L(ln2_hi)		/ ln2_hi, [z], x, [z]
69*25c28e83SPiotr Jasiukajtis	fmulp				/ [z]*ln2_hi, x, [z]
70*25c28e83SPiotr Jasiukajtis	fsubrp	%st,%st(1)		/ x-[z]*ln2_hi, [z]
71*25c28e83SPiotr Jasiukajtis	fldt	PIC_L(ln2_lo)		/ ln2_lo, x-[z]*ln2_hi, [z]
72*25c28e83SPiotr Jasiukajtis	PIC_WRAPUP
73*25c28e83SPiotr Jasiukajtis	fmul	%st(2),%st		/ [z]*ln2_lo, x-[z]*ln2_hi, [z]
74*25c28e83SPiotr Jasiukajtis	fsubrp	%st,%st(1)		/ r := x-[z]*ln(2), [z]
75*25c28e83SPiotr Jasiukajtis	fldl2e				/ log2(e), r, [z]
76*25c28e83SPiotr Jasiukajtis	fmulp				/ f := r*log2(e), [z]
77*25c28e83SPiotr Jasiukajtis	f2xm1				/ 2^f-1,[z]
78*25c28e83SPiotr Jasiukajtis	fld1				/ 1, 2^f-1, [z]
79*25c28e83SPiotr Jasiukajtis	faddp	%st,%st(1)		/ 2^f, [z]
80*25c28e83SPiotr Jasiukajtis	fscale				/ e^x, [z]
81*25c28e83SPiotr Jasiukajtis	fstp	%st(1)			/ e^x
82*25c28e83SPiotr Jasiukajtis	fld1				/ 1, e^x
83*25c28e83SPiotr Jasiukajtis	fsubrp	%st,%st(1)		/ e^x-1
84*25c28e83SPiotr Jasiukajtis	ret
85*25c28e83SPiotr Jasiukajtis
86*25c28e83SPiotr Jasiukajtis.check_tail:
87*25c28e83SPiotr Jasiukajtis	movl	12(%rsp),%ecx		/ ecx <-- hi_32(sgnfcnd(x))
88*25c28e83SPiotr Jasiukajtis	cmpl	$0xb17217f7,%ecx	/ Is |x| < ln(2)?
89*25c28e83SPiotr Jasiukajtis	ja	.finite_non_special
90*25c28e83SPiotr Jasiukajtis	jb	.shortcut
91*25c28e83SPiotr Jasiukajtis	movl	8(%rsp),%edx		/ edx <-- lo_32(x)
92*25c28e83SPiotr Jasiukajtis	cmpl	$0xd1cf79ab,%edx	/ Is |x| slightly < ln(2)?
93*25c28e83SPiotr Jasiukajtis	ja	.finite_non_special	/ branch if |x| slightly > ln(2)
94*25c28e83SPiotr Jasiukajtis.shortcut:
95*25c28e83SPiotr Jasiukajtis	/ Here, |x| < ln(2), so |z| = |x/ln(2)| < 1,
96*25c28e83SPiotr Jasiukajtis	/ whence z is in f2xm1's domain.
97*25c28e83SPiotr Jasiukajtis	fldt	8(%rsp)			/ x
98*25c28e83SPiotr Jasiukajtis	fldl2e				/ log2(e), x
99*25c28e83SPiotr Jasiukajtis	fmulp				/ z := x*log2(e)
100*25c28e83SPiotr Jasiukajtis	f2xm1				/ 2^(x*log2(e))-1 = e^x-1
101*25c28e83SPiotr Jasiukajtis	ret
102*25c28e83SPiotr Jasiukajtis
103*25c28e83SPiotr Jasiukajtis.not_finite:
104*25c28e83SPiotr Jasiukajtis	movl	12(%rsp),%ecx		/ ecx <-- hi_32(sgnfcnd(x))
105*25c28e83SPiotr Jasiukajtis	cmpl	$0x80000000,%ecx	/ hi_32(|x|) = hi_32(INF)?
106*25c28e83SPiotr Jasiukajtis	jne	.NaN_or_pinf		/ if not, x is NaN
107*25c28e83SPiotr Jasiukajtis	movl	8(%rsp),%edx		/ edx <-- lo_32(x)
108*25c28e83SPiotr Jasiukajtis	cmpl	$0,%edx			/ lo_32(x) = 0?
109*25c28e83SPiotr Jasiukajtis	jne	.NaN_or_pinf		/ if not, x is NaN
110*25c28e83SPiotr Jasiukajtis	movl	16(%rsp),%eax		/ ax <-- sign&bexp((x))
111*25c28e83SPiotr Jasiukajtis	andl	$0x8000,%eax		/ here, x is infinite, but +/-?
112*25c28e83SPiotr Jasiukajtis	jz	.NaN_or_pinf		/ branch if x = +INF
113*25c28e83SPiotr Jasiukajtis1:
114*25c28e83SPiotr Jasiukajtis	fld1				/ Here, x = -inf, so return -1
115*25c28e83SPiotr Jasiukajtis	fchs
116*25c28e83SPiotr Jasiukajtis	ret
117*25c28e83SPiotr Jasiukajtis
118*25c28e83SPiotr Jasiukajtis.NaN_or_pinf:
119*25c28e83SPiotr Jasiukajtis	/ Here, x = NaN or +inf, so load x and return immediately.
120*25c28e83SPiotr Jasiukajtis	fldt	8(%rsp)
121*25c28e83SPiotr Jasiukajtis	ret
122*25c28e83SPiotr Jasiukajtis	.align	16
123*25c28e83SPiotr Jasiukajtis	SET_SIZE(expm1l)
124