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1906 | serge | 1 | /* Software floating-point emulation. |
2 | Basic eight-word fraction declaration and manipulation. |
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3 | Copyright (C) 1997,1998,1999,2006 Free Software Foundation, Inc. |
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4 | This file is part of the GNU C Library. |
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5 | Contributed by Richard Henderson (rth@cygnus.com), |
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6 | Jakub Jelinek (jj@ultra.linux.cz) and |
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7 | Peter Maydell (pmaydell@chiark.greenend.org.uk). |
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8 | |||
9 | The GNU C Library is free software; you can redistribute it and/or |
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10 | modify it under the terms of the GNU Lesser General Public |
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11 | License as published by the Free Software Foundation; either |
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12 | version 2.1 of the License, or (at your option) any later version. |
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13 | |||
14 | In addition to the permissions in the GNU Lesser General Public |
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15 | License, the Free Software Foundation gives you unlimited |
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16 | permission to link the compiled version of this file into |
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17 | combinations with other programs, and to distribute those |
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18 | combinations without any restriction coming from the use of this |
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19 | file. (The Lesser General Public License restrictions do apply in |
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20 | other respects; for example, they cover modification of the file, |
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21 | and distribution when not linked into a combine executable.) |
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22 | |||
23 | The GNU C Library is distributed in the hope that it will be useful, |
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24 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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25 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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26 | Lesser General Public License for more details. |
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27 | |||
28 | You should have received a copy of the GNU Lesser General Public |
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29 | License along with the GNU C Library; if not, write to the Free |
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30 | Software Foundation, 51 Franklin Street, Fifth Floor, Boston, |
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31 | MA 02110-1301, USA. */ |
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32 | |||
33 | /* We need just a few things from here for op-4, if we ever need some |
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34 | other macros, they can be added. */ |
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35 | #define _FP_FRAC_DECL_8(X) _FP_W_TYPE X##_f[8] |
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36 | #define _FP_FRAC_HIGH_8(X) (X##_f[7]) |
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37 | #define _FP_FRAC_LOW_8(X) (X##_f[0]) |
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38 | #define _FP_FRAC_WORD_8(X,w) (X##_f[w]) |
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39 | |||
40 | #define _FP_FRAC_SLL_8(X,N) \ |
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41 | do { \ |
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42 | _FP_I_TYPE _up, _down, _skip, _i; \ |
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43 | _skip = (N) / _FP_W_TYPE_SIZE; \ |
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44 | _up = (N) % _FP_W_TYPE_SIZE; \ |
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45 | _down = _FP_W_TYPE_SIZE - _up; \ |
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46 | if (!_up) \ |
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47 | for (_i = 7; _i >= _skip; --_i) \ |
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48 | X##_f[_i] = X##_f[_i-_skip]; \ |
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49 | else \ |
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50 | { \ |
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51 | for (_i = 7; _i > _skip; --_i) \ |
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52 | X##_f[_i] = X##_f[_i-_skip] << _up \ |
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53 | | X##_f[_i-_skip-1] >> _down; \ |
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54 | X##_f[_i--] = X##_f[0] << _up; \ |
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55 | } \ |
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56 | for (; _i >= 0; --_i) \ |
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57 | X##_f[_i] = 0; \ |
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58 | } while (0) |
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59 | |||
60 | #define _FP_FRAC_SRL_8(X,N) \ |
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61 | do { \ |
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62 | _FP_I_TYPE _up, _down, _skip, _i; \ |
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63 | _skip = (N) / _FP_W_TYPE_SIZE; \ |
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64 | _down = (N) % _FP_W_TYPE_SIZE; \ |
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65 | _up = _FP_W_TYPE_SIZE - _down; \ |
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66 | if (!_down) \ |
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67 | for (_i = 0; _i <= 7-_skip; ++_i) \ |
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68 | X##_f[_i] = X##_f[_i+_skip]; \ |
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69 | else \ |
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70 | { \ |
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71 | for (_i = 0; _i < 7-_skip; ++_i) \ |
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72 | X##_f[_i] = X##_f[_i+_skip] >> _down \ |
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73 | | X##_f[_i+_skip+1] << _up; \ |
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74 | X##_f[_i++] = X##_f[7] >> _down; \ |
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75 | } \ |
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76 | for (; _i < 8; ++_i) \ |
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77 | X##_f[_i] = 0; \ |
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78 | } while (0) |
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79 | |||
80 | |||
81 | /* Right shift with sticky-lsb. |
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82 | * What this actually means is that we do a standard right-shift, |
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83 | * but that if any of the bits that fall off the right hand side |
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84 | * were one then we always set the LSbit. |
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85 | */ |
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86 | #define _FP_FRAC_SRS_8(X,N,size) \ |
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87 | do { \ |
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88 | _FP_I_TYPE _up, _down, _skip, _i; \ |
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89 | _FP_W_TYPE _s; \ |
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90 | _skip = (N) / _FP_W_TYPE_SIZE; \ |
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91 | _down = (N) % _FP_W_TYPE_SIZE; \ |
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92 | _up = _FP_W_TYPE_SIZE - _down; \ |
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93 | for (_s = _i = 0; _i < _skip; ++_i) \ |
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94 | _s |= X##_f[_i]; \ |
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95 | if (!_down) \ |
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96 | for (_i = 0; _i <= 7-_skip; ++_i) \ |
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97 | X##_f[_i] = X##_f[_i+_skip]; \ |
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98 | else \ |
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99 | { \ |
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100 | _s |= X##_f[_i] << _up; \ |
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101 | for (_i = 0; _i < 7-_skip; ++_i) \ |
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102 | X##_f[_i] = X##_f[_i+_skip] >> _down \ |
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103 | | X##_f[_i+_skip+1] << _up; \ |
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104 | X##_f[_i++] = X##_f[7] >> _down; \ |
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105 | } \ |
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106 | for (; _i < 8; ++_i) \ |
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107 | X##_f[_i] = 0; \ |
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108 | /* don't fix the LSB until the very end when we're sure f[0] is stable */ \ |
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109 | X##_f[0] |= (_s != 0); \ |
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110 | } while (0)>><>>><>=>>>><>>=>><>><> |
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111 |