5261 libm should stop using synonyms.h
5298 fabs is 0-sized, confuses dis(1) and others
Reviewed by: Josef 'Jeff' Sipek <jeffpc@josefsipek.net>
Approved by: Gordon Ross <gwr@nexenta.com>
1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21 /*
22 * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
23 */
24 /*
25 * Copyright 2005 Sun Microsystems, Inc. All rights reserved.
26 * Use is subject to license terms.
27 */
28
29 .file "exp2l.s"
30
31 #include "libm.h"
32 LIBM_ANSI_PRAGMA_WEAK(exp2l,function)
33 #include "libm_synonyms.h"
34
35 ENTRY(exp2l)
36 movl 16(%rsp),%ecx / cx <--sign&bexp(x)
37 andl $0x7fff,%ecx / ecx <-- zero_xtnd(bexp(x))
38 cmpl $0x3fff,%ecx / Is |x| <= 1?
39 jb .shortcut / If so, take a shortcut.
40 je .check_tail / |x| may be slightly > 1
41 .general_case: / Here, |x| > 1 or x is NaN
42 cmpl $0x7fff,%ecx / bexp(|x|) = bexp(INF)?
43 je .not_finite / if so, x is not finite
44 .finite_non_special: / Here, 1 < |x| < INF
45 fldt 8(%rsp) / push arg
46 fld %st(0) / duplicate stack top
47 frndint / [x],x
48 fucomi %st(1),%st / x integral?
49 je .x_integral / branch if x integral
50 fxch / x, [x]
51 fsub %st(1),%st / x-[x], [x]
52 f2xm1 / 2**(x-[x])-1, [x]
53 fld1 / 1,2**(x-[x])-1, [x]
54 faddp %st,%st(1) / 2**(x-[x]), [x]
55 fscale / 2**x = 2**(arg), [x]
56 fstp %st(1)
57 ret
58
59 .x_integral:
60 fstp %st(0) / ,x
61 fld1 / 1 = 2**0, x
62 fscale / 2**(0 + x) = 2**x, x
63 fstp %st(1) / 2**x
64 ret
65
66 .check_tail:
67 movl 12(%rsp),%ecx / ecx <-- hi_32(sgnfcnd(x))
68 cmpl $0x80000000,%ecx / Is |x| <= 1?
69 ja .finite_non_special
70 movl 8(%rsp),%edx / edx <-- lo_32(sgnfcnd(x))
71 cmpl $0x0,%edx / Is |x| slightly > 1?
72 ja .finite_non_special / branch if |x| slightly > 1
73 .shortcut:
74 / Here, |x| < 1,
75 / whence x is in f2xm1's domain.
76 fldt 8(%rsp) / push x
77 f2xm1 / 2**x - 1
78 fld1 / 1,2**x - 1
79 faddp %st,%st(1) / 2**x
80 ret
81
82 .not_finite:
83 movl 12(%rsp),%ecx / ecx <-- hi_32(sgnfcnd(x))
84 cmpl $0x80000000,%ecx / hi_32(|x|) = hi_32(INF)?
85 jne .NaN_or_pinf / if not, x is NaN
86 movl 8(%rsp),%edx / edx <-- lo_32(x)
87 cmpl $0,%edx / lo_32(x) = 0?
88 jne .NaN_or_pinf / if not, x is NaN
89 movl 16(%rsp),%eax / ax <-- sign&bexp((x))
90 andl $0x8000,%eax / here, x is infinite, but +/-?
91 jz .NaN_or_pinf / branch if x = +INF
92 fldz / Here, x = -inf, so return 0
93 ret
94
95 .NaN_or_pinf:
96 / Here, x = NaN or +inf, so load x and return immediately.
97 fldt 8(%rsp)
98 ret
99 .align 16
100 SET_SIZE(exp2l)
--- EOF ---