projects / thirdparty / glibc.git / blame
| Commit | Line | Data |
|---|---|---|
| 559398ab | 1 | /* floor function, sparc32 v9 vis3 version. |
| 568035b7 | 2 | Copyright (C) 2012-2013 Free Software Foundation, Inc. |
| 559398ab DM |
3 | This file is part of the GNU C Library. |
| 4 | Contributed by David S. Miller <davem@davemloft.net>, 2012. | |
| 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, see | |
| 18 | <http://www.gnu.org/licenses/>. */ | |
| 19 | ||
| 20 | #include <sysdep.h> | |
| 21 | ||
| 22 | /* Since changing the rounding mode is extremely expensive, we | |
| 23 | try to round up using a method that is rounding mode | |
| 24 | agnostic. | |
| 25 | ||
| 26 | We add then subtract (or subtract than add if the initial | |
| 27 | value was negative) 2**23 to the value, then subtract it | |
| 28 | back out. | |
| 29 | ||
| 30 | This will clear out the fractional portion of the value. | |
| 31 | One of two things will happen for non-whole initial values. | |
| 32 | Either the rounding mode will round it up, or it will be | |
| 33 | rounded down. If the value started out whole, it will be | |
| 34 | equal after the addition and subtraction. This means we | |
| 35 | can accurately detect with one test whether we need to add | |
| 36 | another 1.0 to round it up properly. | |
| 37 | ||
| 38 | VIS instructions are used to facilitate the formation of | |
| 39 | easier constants, and the propagation of the sign bit. */ | |
| 40 | ||
| 41 | #define TWO_FIFTYTWO 0x43300000 /* 2**52 */ | |
| 42 | #define ONE_DOT_ZERO 0x3ff00000 /* 1.0 */ | |
| 43 | ||
| 44 | #define ZERO %f10 /* 0.0 */ | |
| 45 | #define SIGN_BIT %f12 /* -0.0 */ | |
| 46 | ||
| 47 | ENTRY (__floor_vis3) | |
| 48 | sethi %hi(TWO_FIFTYTWO), %o2 | |
| 49 | sllx %o0, 32, %o0 | |
| 50 | sethi %hi(ONE_DOT_ZERO), %o3 | |
| 51 | or %o0, %o1, %o0 | |
| 52 | movxtod %o0, %f0 | |
| 53 | sllx %o2, 32, %o2 | |
| 54 | fzero ZERO | |
| 55 | sllx %o3, 32, %o3 | |
| 56 | ||
| 57 | fnegd ZERO, SIGN_BIT | |
| 58 | ||
| ee0db190 | 59 | movxtod %o2, %f16 |
| 559398ab DM |
60 | fabsd %f0, %f14 |
| 61 | ||
| 559398ab DM |
62 | fcmpd %fcc3, %f14, %f16 |
| 63 | ||
| 64 | fmovduge %fcc3, ZERO, %f16 | |
| 65 | fand %f0, SIGN_BIT, SIGN_BIT | |
| 66 | ||
| 67 | for %f16, SIGN_BIT, %f16 | |
| 68 | faddd %f0, %f16, %f18 | |
| 69 | fsubd %f18, %f16, %f18 | |
| 70 | fcmpd %fcc2, %f18, %f0 | |
| 71 | movxtod %o3, %f20 | |
| 72 | ||
| 73 | fmovdule %fcc2, ZERO, %f20 | |
| 74 | fsubd %f18, %f20, %f0 | |
| 75 | fabsd %f0, %f0 | |
| 76 | retl | |
| 77 | for %f0, SIGN_BIT, %f0 | |
| 78 | END (__floor_vis3) |