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9dc874df | 1 | /* Copyright (C) 1998, 1999, 2000 Free Software Foundation, Inc. |
d7bb0de1 RH |
2 | This file is part of the GNU C Library. |
3 | Contributed by Richard Henderson. | |
4 | ||
5 | The GNU C Library is free software; you can redistribute it and/or | |
6 | modify it under the terms of the GNU Library General Public License as | |
7 | published by the Free Software Foundation; either version 2 of the | |
8 | License, or (at your option) any later version. | |
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 | |
13 | Library General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU Library General Public | |
16 | License along with the GNU C Library; see the file COPYING.LIB. If not, | |
17 | write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
18 | Boston, MA 02111-1307, USA. */ | |
19 | ||
d7bb0de1 RH |
20 | #include <math.h> |
21 | ||
92a38c35 UD |
22 | |
23 | /* Use the -inf rounding mode conversion instructions to implement | |
24 | floor. We note when the exponent is large enough that the value | |
25 | must be integral, as this avoids unpleasant integer overflows. */ | |
d7bb0de1 RH |
26 | |
27 | double | |
28 | __floor (double x) | |
29 | { | |
9dc874df | 30 | if (isless (fabs (x), 9007199254740992.0)) /* 1 << DBL_MANT_DIG */ |
f8aa4987 | 31 | { |
9dc874df RH |
32 | double tmp1, new_x; |
33 | ||
f8aa4987 UD |
34 | __asm ( |
35 | #ifdef _IEEE_FP_INEXACT | |
36 | "cvttq/svim %2,%1\n\t" | |
37 | #else | |
38 | "cvttq/svm %2,%1\n\t" | |
39 | #endif | |
40 | "cvtqt/m %1,%0\n\t" | |
9dc874df | 41 | : "=f"(new_x), "=&f"(tmp1) |
f8aa4987 | 42 | : "f"(x)); |
9dc874df RH |
43 | |
44 | /* floor(-0) == -0, and in general we'll always have the same | |
45 | sign as our input. */ | |
46 | x = copysign(new_x, x); | |
f8aa4987 UD |
47 | } |
48 | return x; | |
d7bb0de1 RH |
49 | } |
50 | ||
51 | weak_alias (__floor, floor) | |
52 | #ifdef NO_LONG_DOUBLE | |
53 | strong_alias (__floor, __floorl) | |
54 | weak_alias (__floor, floorl) | |
55 | #endif |