| lh | 9ed821d | 2023-04-07 01:36:19 -0700 | [diff] [blame^] | 1 | /* Set current rounding direction. |
| 2 | Copyright (C) 1997, 2003, 2004, 2005 Free Software Foundation, Inc. |
| 3 | This file is part of the GNU C Library. |
| 4 | Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997. |
| 5 | |
| 6 | The GNU C Library is free software; you can redistribute it and/or |
| 7 | modify it under the terms of the GNU Lesser General Public |
| 8 | License as published by the Free Software Foundation; either |
| 9 | version 2.1 of the License, or (at your option) any later version. |
| 10 | |
| 11 | The GNU C Library is distributed in the hope that it will be useful, |
| 12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 14 | Lesser General Public License for more details. |
| 15 | |
| 16 | You should have received a copy of the GNU Lesser General Public |
| 17 | License along with the GNU C Library; if not, write to the Free |
| 18 | Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
| 19 | 02111-1307 USA. */ |
| 20 | |
| 21 | #include <fenv.h> |
| 22 | #include <unistd.h> |
| 23 | |
| 24 | int |
| 25 | fesetround (int round) |
| 26 | { |
| 27 | unsigned short int cw; |
| 28 | |
| 29 | if ((round & ~0xc00) != 0) |
| 30 | /* ROUND is no valid rounding mode. */ |
| 31 | return 1; |
| 32 | |
| 33 | __asm__ ("fnstcw %0" : "=m" (*&cw)); |
| 34 | cw &= ~0xc00; |
| 35 | cw |= round; |
| 36 | __asm__ ("fldcw %0" : : "m" (*&cw)); |
| 37 | |
| 38 | #if 0 |
| 39 | /* If the CPU supports SSE we set the MXCSR as well. */ |
| 40 | if ((GLRO(dl_hwcap) & HWCAP_I386_XMM) != 0) |
| 41 | { |
| 42 | unsigned int xcw; |
| 43 | |
| 44 | __asm__ ("stmxcsr %0" : "=m" (*&xcw)); |
| 45 | xcw &= ~0x6000; |
| 46 | xcw |= round << 3; |
| 47 | __asm__ ("ldmxcsr %0" : : "m" (*&xcw)); |
| 48 | } |
| 49 | #endif |
| 50 | |
| 51 | return 0; |
| 52 | } |