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6973fc01 | 1 | /* Compute maximum of two numbers, regarding NaN as missing argument. |
2b778ceb | 2 | Copyright (C) 1997-2021 Free Software Foundation, Inc. |
6973fc01 | 3 | This file is part of the GNU C Library. |
6973fc01 UD |
4 | |
5 | The GNU C Library is free software; you can redistribute it and/or | |
41bdb6e2 AJ |
6 | modify it under the terms of the GNU Lesser General Public |
7 | License as published by the Free Software Foundation; either | |
8 | version 2.1 of the License, or (at your option) any later version. | |
6973fc01 UD |
9 | |
10 | The GNU C Library is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
41bdb6e2 | 13 | Lesser General Public License for more details. |
6973fc01 | 14 | |
41bdb6e2 | 15 | You should have received a copy of the GNU Lesser General Public |
59ba27a6 | 16 | License along with the GNU C Library; if not, see |
5a82c748 | 17 | <https://www.gnu.org/licenses/>. */ |
6973fc01 | 18 | |
2ce30701 | 19 | #include <libm-alias-ldouble.h> |
6973fc01 UD |
20 | #include <sysdep.h> |
21 | ||
22 | .text | |
23 | ENTRY(__fmaxl) | |
24 | fldt 16(%esp) // y | |
25 | fxam | |
26 | fnstsw | |
27 | fldt 4(%esp) // y : x | |
28 | ||
29 | andb $0x45, %ah | |
30 | cmpb $0x01, %ah | |
0a2546cd JM |
31 | je 2f // y == NaN |
32 | ||
33 | fxam | |
34 | fnstsw | |
35 | andb $0x45, %ah | |
36 | cmpb $0x01, %ah | |
37 | je 3f // x == NaN | |
6973fc01 UD |
38 | |
39 | fucom %st(1) | |
40 | fnstsw | |
41 | sahf | |
42 | jnc 1f | |
43 | ||
44 | fxch %st(1) | |
45 | 1: fstp %st(1) | |
46 | ||
47 | ret | |
0a2546cd JM |
48 | |
49 | 2: // st(1) is a NaN; st(0) may or may not be. | |
50 | fxam | |
51 | fnstsw | |
52 | andb $0x45, %ah | |
53 | cmpb $0x01, %ah | |
54 | je 4f | |
55 | // st(1) is a NaN; st(0) is not. Test if st(1) is signaling. | |
56 | testb $0x40, 23(%esp) | |
57 | jz 4f | |
58 | fstp %st(1) | |
59 | ret | |
60 | ||
61 | 3: // st(0) is a NaN; st(1) is not. Test if st(0) is signaling. | |
62 | testb $0x40, 11(%esp) | |
63 | jz 4f | |
64 | fstp %st(0) | |
65 | ret | |
66 | ||
67 | 4: // Both arguments are NaNs, or one is a signaling NaN. | |
68 | faddp | |
69 | ret | |
6973fc01 | 70 | END(__fmaxl) |
2ce30701 | 71 | libm_alias_ldouble (__fmax, fmax) |