1169689Skan/* Software floating-point emulation. 2169689Skan Basic eight-word fraction declaration and manipulation. 3169689Skan Copyright (C) 1997,1998,1999,2006 Free Software Foundation, Inc. 4169689Skan This file is part of the GNU C Library. 5169689Skan Contributed by Richard Henderson (rth@cygnus.com), 6169689Skan Jakub Jelinek (jj@ultra.linux.cz) and 7169689Skan Peter Maydell (pmaydell@chiark.greenend.org.uk). 8169689Skan 9169689Skan The GNU C Library is free software; you can redistribute it and/or 10169689Skan modify it under the terms of the GNU Lesser General Public 11169689Skan License as published by the Free Software Foundation; either 12169689Skan version 2.1 of the License, or (at your option) any later version. 13169689Skan 14169689Skan In addition to the permissions in the GNU Lesser General Public 15169689Skan License, the Free Software Foundation gives you unlimited 16169689Skan permission to link the compiled version of this file into 17169689Skan combinations with other programs, and to distribute those 18169689Skan combinations without any restriction coming from the use of this 19169689Skan file. (The Lesser General Public License restrictions do apply in 20169689Skan other respects; for example, they cover modification of the file, 21169689Skan and distribution when not linked into a combine executable.) 22169689Skan 23169689Skan The GNU C Library is distributed in the hope that it will be useful, 24169689Skan but WITHOUT ANY WARRANTY; without even the implied warranty of 25169689Skan MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 26169689Skan Lesser General Public License for more details. 27169689Skan 28169689Skan You should have received a copy of the GNU Lesser General Public 29169689Skan License along with the GNU C Library; if not, write to the Free 30169689Skan Software Foundation, 51 Franklin Street, Fifth Floor, Boston, 31169689Skan MA 02110-1301, USA. */ 32169689Skan 33169689Skan/* We need just a few things from here for op-4, if we ever need some 34169689Skan other macros, they can be added. */ 35169689Skan#define _FP_FRAC_DECL_8(X) _FP_W_TYPE X##_f[8] 36169689Skan#define _FP_FRAC_HIGH_8(X) (X##_f[7]) 37169689Skan#define _FP_FRAC_LOW_8(X) (X##_f[0]) 38169689Skan#define _FP_FRAC_WORD_8(X,w) (X##_f[w]) 39169689Skan 40169689Skan#define _FP_FRAC_SLL_8(X,N) \ 41169689Skan do { \ 42169689Skan _FP_I_TYPE _up, _down, _skip, _i; \ 43169689Skan _skip = (N) / _FP_W_TYPE_SIZE; \ 44169689Skan _up = (N) % _FP_W_TYPE_SIZE; \ 45169689Skan _down = _FP_W_TYPE_SIZE - _up; \ 46169689Skan if (!_up) \ 47169689Skan for (_i = 7; _i >= _skip; --_i) \ 48169689Skan X##_f[_i] = X##_f[_i-_skip]; \ 49169689Skan else \ 50169689Skan { \ 51169689Skan for (_i = 7; _i > _skip; --_i) \ 52169689Skan X##_f[_i] = X##_f[_i-_skip] << _up \ 53169689Skan | X##_f[_i-_skip-1] >> _down; \ 54169689Skan X##_f[_i--] = X##_f[0] << _up; \ 55169689Skan } \ 56169689Skan for (; _i >= 0; --_i) \ 57169689Skan X##_f[_i] = 0; \ 58169689Skan } while (0) 59169689Skan 60169689Skan#define _FP_FRAC_SRL_8(X,N) \ 61169689Skan do { \ 62169689Skan _FP_I_TYPE _up, _down, _skip, _i; \ 63169689Skan _skip = (N) / _FP_W_TYPE_SIZE; \ 64169689Skan _down = (N) % _FP_W_TYPE_SIZE; \ 65169689Skan _up = _FP_W_TYPE_SIZE - _down; \ 66169689Skan if (!_down) \ 67169689Skan for (_i = 0; _i <= 7-_skip; ++_i) \ 68169689Skan X##_f[_i] = X##_f[_i+_skip]; \ 69169689Skan else \ 70169689Skan { \ 71169689Skan for (_i = 0; _i < 7-_skip; ++_i) \ 72169689Skan X##_f[_i] = X##_f[_i+_skip] >> _down \ 73169689Skan | X##_f[_i+_skip+1] << _up; \ 74169689Skan X##_f[_i++] = X##_f[7] >> _down; \ 75169689Skan } \ 76169689Skan for (; _i < 8; ++_i) \ 77169689Skan X##_f[_i] = 0; \ 78169689Skan } while (0) 79169689Skan 80169689Skan 81169689Skan/* Right shift with sticky-lsb. 82169689Skan * What this actually means is that we do a standard right-shift, 83169689Skan * but that if any of the bits that fall off the right hand side 84169689Skan * were one then we always set the LSbit. 85169689Skan */ 86169689Skan#define _FP_FRAC_SRS_8(X,N,size) \ 87169689Skan do { \ 88169689Skan _FP_I_TYPE _up, _down, _skip, _i; \ 89169689Skan _FP_W_TYPE _s; \ 90169689Skan _skip = (N) / _FP_W_TYPE_SIZE; \ 91169689Skan _down = (N) % _FP_W_TYPE_SIZE; \ 92169689Skan _up = _FP_W_TYPE_SIZE - _down; \ 93169689Skan for (_s = _i = 0; _i < _skip; ++_i) \ 94169689Skan _s |= X##_f[_i]; \ 95169689Skan if (!_down) \ 96169689Skan for (_i = 0; _i <= 7-_skip; ++_i) \ 97169689Skan X##_f[_i] = X##_f[_i+_skip]; \ 98169689Skan else \ 99169689Skan { \ 100169689Skan _s |= X##_f[_i] << _up; \ 101169689Skan for (_i = 0; _i < 7-_skip; ++_i) \ 102169689Skan X##_f[_i] = X##_f[_i+_skip] >> _down \ 103169689Skan | X##_f[_i+_skip+1] << _up; \ 104169689Skan X##_f[_i++] = X##_f[7] >> _down; \ 105169689Skan } \ 106169689Skan for (; _i < 8; ++_i) \ 107169689Skan X##_f[_i] = 0; \ 108169689Skan /* don't fix the LSB until the very end when we're sure f[0] is stable */ \ 109169689Skan X##_f[0] |= (_s != 0); \ 110169689Skan } while (0) 111169689Skan 112