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1 /* Software floating-point emulation.
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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
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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
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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
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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
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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
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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
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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
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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
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80
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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
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