| 1 | /* Compute maximum of two numbers, regarding NaN as missing argument. |
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| 2 | Copyright (C) 1997-2022 Free Software Foundation, Inc. |
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| 3 | This file is part of the GNU C Library. |
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| 4 | |
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| 5 | The GNU C Library is free software; you can redistribute it and/or |
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| 6 | modify it under the terms of the GNU Lesser General Public |
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| 7 | License as published by the Free Software Foundation; either |
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| 8 | version 2.1 of the License, or (at your option) any later version. |
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| 9 | |
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| 10 | The GNU C Library is distributed in the hope that it will be useful, |
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| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 13 | Lesser General Public License for more details. |
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| 14 | |
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| 15 | You should have received a copy of the GNU Lesser General Public |
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| 16 | License along with the GNU C Library; if not, see |
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| 17 | <https://www.gnu.org/licenses/>. */ |
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| 18 | |
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| 19 | #include <libm-alias-ldouble.h> |
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| 20 | #include <sysdep.h> |
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| 21 | |
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| 22 | .text |
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| 23 | ENTRY(__fmaxl) |
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| 24 | fldt 16(%esp) // y |
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| 25 | fxam |
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| 26 | fnstsw |
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| 27 | fldt 4(%esp) // y : x |
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| 28 | |
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| 29 | andb $0x45, %ah |
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| 30 | cmpb $0x01, %ah |
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| 31 | je 2f // y == NaN |
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| 32 | |
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| 33 | fxam |
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| 34 | fnstsw |
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| 35 | andb $0x45, %ah |
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| 36 | cmpb $0x01, %ah |
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| 37 | je 3f // x == NaN |
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| 38 | |
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| 39 | fucom %st(1) |
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| 40 | fnstsw |
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| 41 | sahf |
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| 42 | jnc 1f |
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| 43 | |
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| 44 | fxch %st(1) |
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| 45 | 1: fstp %st(1) |
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| 46 | |
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| 47 | ret |
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| 48 | |
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| 49 | 2: // st(1) is a NaN; st(0) may or may not be. |
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| 50 | fxam |
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| 51 | fnstsw |
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| 52 | andb $0x45, %ah |
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| 53 | cmpb $0x01, %ah |
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| 54 | je 4f |
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| 55 | // st(1) is a NaN; st(0) is not. Test if st(1) is signaling. |
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| 56 | testb $0x40, 23(%esp) |
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| 57 | jz 4f |
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| 58 | fstp %st(1) |
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| 59 | ret |
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| 60 | |
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| 61 | 3: // st(0) is a NaN; st(1) is not. Test if st(0) is signaling. |
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| 62 | testb $0x40, 11(%esp) |
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| 63 | jz 4f |
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| 64 | fstp %st(0) |
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| 65 | ret |
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| 66 | |
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| 67 | 4: // Both arguments are NaNs, or one is a signaling NaN. |
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| 68 | faddp |
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| 69 | ret |
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| 70 | END(__fmaxl) |
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| 71 | libm_alias_ldouble (__fmax, fmax) |
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| 72 | |
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