Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame^] | 1 | /* Software floating-point emulation. |
| 2 | Basic eight-word fraction declaration and manipulation. |
| 3 | Copyright (C) 1997,1998,1999 Free Software Foundation, Inc. |
| 4 | This file is part of the GNU C Library. |
| 5 | Contributed by Richard Henderson (rth@cygnus.com), |
| 6 | Jakub Jelinek (jj@ultra.linux.cz) and |
| 7 | Peter Maydell (pmaydell@chiark.greenend.org.uk). |
| 8 | |
| 9 | The GNU C Library is free software; you can redistribute it and/or |
| 10 | modify it under the terms of the GNU Library General Public License as |
| 11 | published by the Free Software Foundation; either version 2 of the |
| 12 | License, or (at your option) any later version. |
| 13 | |
| 14 | The GNU C Library is distributed in the hope that it will be useful, |
| 15 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 17 | Library General Public License for more details. |
| 18 | |
| 19 | You should have received a copy of the GNU Library General Public |
| 20 | License along with the GNU C Library; see the file COPYING.LIB. If |
| 21 | not, write to the Free Software Foundation, Inc., |
| 22 | 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ |
| 23 | |
| 24 | #ifndef __MATH_EMU_OP_8_H__ |
| 25 | #define __MATH_EMU_OP_8_H__ |
| 26 | |
| 27 | /* We need just a few things from here for op-4, if we ever need some |
| 28 | other macros, they can be added. */ |
| 29 | #define _FP_FRAC_DECL_8(X) _FP_W_TYPE X##_f[8] |
| 30 | #define _FP_FRAC_HIGH_8(X) (X##_f[7]) |
| 31 | #define _FP_FRAC_LOW_8(X) (X##_f[0]) |
| 32 | #define _FP_FRAC_WORD_8(X,w) (X##_f[w]) |
| 33 | |
| 34 | #define _FP_FRAC_SLL_8(X,N) \ |
| 35 | do { \ |
| 36 | _FP_I_TYPE _up, _down, _skip, _i; \ |
| 37 | _skip = (N) / _FP_W_TYPE_SIZE; \ |
| 38 | _up = (N) % _FP_W_TYPE_SIZE; \ |
| 39 | _down = _FP_W_TYPE_SIZE - _up; \ |
| 40 | if (!_up) \ |
| 41 | for (_i = 7; _i >= _skip; --_i) \ |
| 42 | X##_f[_i] = X##_f[_i-_skip]; \ |
| 43 | else \ |
| 44 | { \ |
| 45 | for (_i = 7; _i > _skip; --_i) \ |
| 46 | X##_f[_i] = X##_f[_i-_skip] << _up \ |
| 47 | | X##_f[_i-_skip-1] >> _down; \ |
| 48 | X##_f[_i--] = X##_f[0] << _up; \ |
| 49 | } \ |
| 50 | for (; _i >= 0; --_i) \ |
| 51 | X##_f[_i] = 0; \ |
| 52 | } while (0) |
| 53 | |
| 54 | #define _FP_FRAC_SRL_8(X,N) \ |
| 55 | do { \ |
| 56 | _FP_I_TYPE _up, _down, _skip, _i; \ |
| 57 | _skip = (N) / _FP_W_TYPE_SIZE; \ |
| 58 | _down = (N) % _FP_W_TYPE_SIZE; \ |
| 59 | _up = _FP_W_TYPE_SIZE - _down; \ |
| 60 | if (!_down) \ |
| 61 | for (_i = 0; _i <= 7-_skip; ++_i) \ |
| 62 | X##_f[_i] = X##_f[_i+_skip]; \ |
| 63 | else \ |
| 64 | { \ |
| 65 | for (_i = 0; _i < 7-_skip; ++_i) \ |
| 66 | X##_f[_i] = X##_f[_i+_skip] >> _down \ |
| 67 | | X##_f[_i+_skip+1] << _up; \ |
| 68 | X##_f[_i++] = X##_f[7] >> _down; \ |
| 69 | } \ |
| 70 | for (; _i < 8; ++_i) \ |
| 71 | X##_f[_i] = 0; \ |
| 72 | } while (0) |
| 73 | |
| 74 | |
| 75 | /* Right shift with sticky-lsb. |
| 76 | * What this actually means is that we do a standard right-shift, |
| 77 | * but that if any of the bits that fall off the right hand side |
| 78 | * were one then we always set the LSbit. |
| 79 | */ |
| 80 | #define _FP_FRAC_SRS_8(X,N,size) \ |
| 81 | do { \ |
| 82 | _FP_I_TYPE _up, _down, _skip, _i; \ |
| 83 | _FP_W_TYPE _s; \ |
| 84 | _skip = (N) / _FP_W_TYPE_SIZE; \ |
| 85 | _down = (N) % _FP_W_TYPE_SIZE; \ |
| 86 | _up = _FP_W_TYPE_SIZE - _down; \ |
| 87 | for (_s = _i = 0; _i < _skip; ++_i) \ |
| 88 | _s |= X##_f[_i]; \ |
| 89 | _s |= X##_f[_i] << _up; \ |
| 90 | /* s is now != 0 if we want to set the LSbit */ \ |
| 91 | if (!_down) \ |
| 92 | for (_i = 0; _i <= 7-_skip; ++_i) \ |
| 93 | X##_f[_i] = X##_f[_i+_skip]; \ |
| 94 | else \ |
| 95 | { \ |
| 96 | for (_i = 0; _i < 7-_skip; ++_i) \ |
| 97 | X##_f[_i] = X##_f[_i+_skip] >> _down \ |
| 98 | | X##_f[_i+_skip+1] << _up; \ |
| 99 | X##_f[_i++] = X##_f[7] >> _down; \ |
| 100 | } \ |
| 101 | for (; _i < 8; ++_i) \ |
| 102 | X##_f[_i] = 0; \ |
| 103 | /* don't fix the LSB until the very end when we're sure f[0] is stable */ \ |
| 104 | X##_f[0] |= (_s != 0); \ |
| 105 | } while (0) |
| 106 | |
| 107 | #endif |