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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 |