| |
| /*============================================================================ |
| |
| This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic |
| Package, Release 3, by John R. Hauser. |
| |
| Copyright 2011, 2012, 2013, 2014 The Regents of the University of California |
| (Regents). All Rights Reserved. Redistribution and use in source and binary |
| forms, with or without modification, are permitted provided that the following |
| conditions are met: |
| |
| Redistributions of source code must retain the above copyright notice, |
| this list of conditions, and the following two paragraphs of disclaimer. |
| Redistributions in binary form must reproduce the above copyright notice, |
| this list of conditions, and the following two paragraphs of disclaimer in the |
| documentation and/or other materials provided with the distribution. Neither |
| the name of the Regents nor the names of its contributors may be used to |
| endorse or promote products derived from this software without specific prior |
| written permission. |
| |
| IN NO EVENT SHALL REGENTS BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT, |
| SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING LOST PROFITS, ARISING |
| OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF REGENTS HAS |
| BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| |
| REGENTS SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT LIMITED |
| TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
| PURPOSE. THE SOFTWARE AND ACCOMPANYING DOCUMENTATION, IF ANY, PROVIDED |
| HEREUNDER IS PROVIDED "AS IS". REGENTS HAS NO OBLIGATION TO PROVIDE |
| MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS. |
| |
| =============================================================================*/ |
| |
| #include <stdint.h> |
| #include "platform.h" |
| #include "primitives.h" |
| |
| #ifndef softfloat_approxRecip32_1 |
| |
| uint32_t softfloat_approxRecip32_1( uint32_t a ) |
| { |
| int index; |
| uint16_t eps; |
| static const uint16_t k0s[] = { |
| 0xFFC4, 0xF0BE, 0xE363, 0xD76F, 0xCCAD, 0xC2F0, 0xBA16, 0xB201, |
| 0xAA97, 0xA3C6, 0x9D7A, 0x97A6, 0x923C, 0x8D32, 0x887E, 0x8417 |
| }; |
| static const uint16_t k1s[] = { |
| 0xF0F1, 0xD62C, 0xBFA1, 0xAC77, 0x9C0A, 0x8DDB, 0x8185, 0x76BA, |
| 0x6D3B, 0x64D4, 0x5D5C, 0x56B1, 0x50B6, 0x4B55, 0x4679, 0x4211 |
| }; |
| uint16_t r0; |
| uint32_t delta0; |
| uint_fast32_t r; |
| uint32_t sqrDelta0; |
| |
| index = a>>27 & 0xF; |
| eps = (uint16_t) (a>>11); |
| r0 = k0s[index] - ((k1s[index] * (uint_fast32_t) eps)>>20); |
| delta0 = ~(uint_fast32_t) ((r0 * (uint_fast64_t) a)>>7); |
| r = ((uint_fast32_t) r0<<16) + ((r0 * (uint_fast64_t) delta0)>>24); |
| sqrDelta0 = ((uint_fast64_t) delta0 * delta0)>>32; |
| r += ((uint32_t) r * (uint_fast64_t) sqrDelta0)>>48; |
| return r; |
| |
| } |
| |
| #endif |
| |