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d876f532 UD |
1 | /* Software floating-point emulation. |
2 | Basic one-word fraction declaration and manipulation. | |
fe0b1e85 | 3 | Copyright (C) 1997,1998,1999,2006 Free Software Foundation, Inc. |
d876f532 UD |
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), | |
7 | David S. Miller (davem@redhat.com) and | |
8 | Peter Maydell (pmaydell@chiark.greenend.org.uk). | |
9 | ||
10 | The GNU C Library is free software; you can redistribute it and/or | |
41bdb6e2 AJ |
11 | modify it under the terms of the GNU Lesser General Public |
12 | License as published by the Free Software Foundation; either | |
13 | version 2.1 of the License, or (at your option) any later version. | |
d876f532 | 14 | |
638a783c RM |
15 | In addition to the permissions in the GNU Lesser General Public |
16 | License, the Free Software Foundation gives you unlimited | |
17 | permission to link the compiled version of this file into | |
18 | combinations with other programs, and to distribute those | |
19 | combinations without any restriction coming from the use of this | |
20 | file. (The Lesser General Public License restrictions do apply in | |
21 | other respects; for example, they cover modification of the file, | |
22 | and distribution when not linked into a combine executable.) | |
23 | ||
d876f532 UD |
24 | The GNU C Library is distributed in the hope that it will be useful, |
25 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
26 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
41bdb6e2 | 27 | Lesser General Public License for more details. |
d876f532 | 28 | |
41bdb6e2 AJ |
29 | You should have received a copy of the GNU Lesser General Public |
30 | License along with the GNU C Library; if not, write to the Free | |
638a783c RM |
31 | Software Foundation, 51 Franklin Street, Fifth Floor, Boston, |
32 | MA 02110-1301, USA. */ | |
d876f532 UD |
33 | |
34 | #define _FP_FRAC_DECL_1(X) _FP_W_TYPE X##_f | |
35 | #define _FP_FRAC_COPY_1(D,S) (D##_f = S##_f) | |
36 | #define _FP_FRAC_SET_1(X,I) (X##_f = I) | |
37 | #define _FP_FRAC_HIGH_1(X) (X##_f) | |
38 | #define _FP_FRAC_LOW_1(X) (X##_f) | |
39 | #define _FP_FRAC_WORD_1(X,w) (X##_f) | |
40 | ||
41 | #define _FP_FRAC_ADDI_1(X,I) (X##_f += I) | |
42 | #define _FP_FRAC_SLL_1(X,N) \ | |
43 | do { \ | |
44 | if (__builtin_constant_p(N) && (N) == 1) \ | |
45 | X##_f += X##_f; \ | |
46 | else \ | |
47 | X##_f <<= (N); \ | |
48 | } while (0) | |
49 | #define _FP_FRAC_SRL_1(X,N) (X##_f >>= N) | |
50 | ||
51 | /* Right shift with sticky-lsb. */ | |
fe0b1e85 | 52 | #define _FP_FRAC_SRST_1(X,S,N,sz) __FP_FRAC_SRST_1(X##_f, S, N, sz) |
d876f532 UD |
53 | #define _FP_FRAC_SRS_1(X,N,sz) __FP_FRAC_SRS_1(X##_f, N, sz) |
54 | ||
fe0b1e85 RM |
55 | #define __FP_FRAC_SRST_1(X,S,N,sz) \ |
56 | do { \ | |
57 | S = (__builtin_constant_p(N) && (N) == 1 \ | |
58 | ? X & 1 : (X << (_FP_W_TYPE_SIZE - (N))) != 0); \ | |
59 | X = X >> (N); \ | |
60 | } while (0) | |
61 | ||
d876f532 UD |
62 | #define __FP_FRAC_SRS_1(X,N,sz) \ |
63 | (X = (X >> (N) | (__builtin_constant_p(N) && (N) == 1 \ | |
64 | ? X & 1 : (X << (_FP_W_TYPE_SIZE - (N))) != 0))) | |
65 | ||
66 | #define _FP_FRAC_ADD_1(R,X,Y) (R##_f = X##_f + Y##_f) | |
67 | #define _FP_FRAC_SUB_1(R,X,Y) (R##_f = X##_f - Y##_f) | |
68 | #define _FP_FRAC_DEC_1(X,Y) (X##_f -= Y##_f) | |
69 | #define _FP_FRAC_CLZ_1(z, X) __FP_CLZ(z, X##_f) | |
70 | ||
71 | /* Predicates */ | |
72 | #define _FP_FRAC_NEGP_1(X) ((_FP_WS_TYPE)X##_f < 0) | |
73 | #define _FP_FRAC_ZEROP_1(X) (X##_f == 0) | |
74 | #define _FP_FRAC_OVERP_1(fs,X) (X##_f & _FP_OVERFLOW_##fs) | |
cf299341 | 75 | #define _FP_FRAC_CLEAR_OVERP_1(fs,X) (X##_f &= ~_FP_OVERFLOW_##fs) |
d876f532 UD |
76 | #define _FP_FRAC_EQ_1(X, Y) (X##_f == Y##_f) |
77 | #define _FP_FRAC_GE_1(X, Y) (X##_f >= Y##_f) | |
78 | #define _FP_FRAC_GT_1(X, Y) (X##_f > Y##_f) | |
79 | ||
80 | #define _FP_ZEROFRAC_1 0 | |
81 | #define _FP_MINFRAC_1 1 | |
82 | #define _FP_MAXFRAC_1 (~(_FP_WS_TYPE)0) | |
83 | ||
84 | /* | |
85 | * Unpack the raw bits of a native fp value. Do not classify or | |
86 | * normalize the data. | |
87 | */ | |
88 | ||
89 | #define _FP_UNPACK_RAW_1(fs, X, val) \ | |
90 | do { \ | |
91 | union _FP_UNION_##fs _flo; _flo.flt = (val); \ | |
92 | \ | |
93 | X##_f = _flo.bits.frac; \ | |
94 | X##_e = _flo.bits.exp; \ | |
95 | X##_s = _flo.bits.sign; \ | |
96 | } while (0) | |
97 | ||
98 | #define _FP_UNPACK_RAW_1_P(fs, X, val) \ | |
99 | do { \ | |
100 | union _FP_UNION_##fs *_flo = \ | |
101 | (union _FP_UNION_##fs *)(val); \ | |
102 | \ | |
103 | X##_f = _flo->bits.frac; \ | |
104 | X##_e = _flo->bits.exp; \ | |
105 | X##_s = _flo->bits.sign; \ | |
106 | } while (0) | |
107 | ||
108 | /* | |
109 | * Repack the raw bits of a native fp value. | |
110 | */ | |
111 | ||
112 | #define _FP_PACK_RAW_1(fs, val, X) \ | |
113 | do { \ | |
114 | union _FP_UNION_##fs _flo; \ | |
115 | \ | |
116 | _flo.bits.frac = X##_f; \ | |
117 | _flo.bits.exp = X##_e; \ | |
118 | _flo.bits.sign = X##_s; \ | |
119 | \ | |
120 | (val) = _flo.flt; \ | |
121 | } while (0) | |
122 | ||
123 | #define _FP_PACK_RAW_1_P(fs, val, X) \ | |
124 | do { \ | |
125 | union _FP_UNION_##fs *_flo = \ | |
126 | (union _FP_UNION_##fs *)(val); \ | |
127 | \ | |
128 | _flo->bits.frac = X##_f; \ | |
129 | _flo->bits.exp = X##_e; \ | |
130 | _flo->bits.sign = X##_s; \ | |
131 | } while (0) | |
132 | ||
133 | ||
134 | /* | |
135 | * Multiplication algorithms: | |
136 | */ | |
137 | ||
138 | /* Basic. Assuming the host word size is >= 2*FRACBITS, we can do the | |
139 | multiplication immediately. */ | |
140 | ||
141 | #define _FP_MUL_MEAT_1_imm(wfracbits, R, X, Y) \ | |
142 | do { \ | |
143 | R##_f = X##_f * Y##_f; \ | |
144 | /* Normalize since we know where the msb of the multiplicands \ | |
145 | were (bit B), we know that the msb of the of the product is \ | |
146 | at either 2B or 2B-1. */ \ | |
147 | _FP_FRAC_SRS_1(R, wfracbits-1, 2*wfracbits); \ | |
148 | } while (0) | |
149 | ||
150 | /* Given a 1W * 1W => 2W primitive, do the extended multiplication. */ | |
151 | ||
152 | #define _FP_MUL_MEAT_1_wide(wfracbits, R, X, Y, doit) \ | |
153 | do { \ | |
154 | _FP_W_TYPE _Z_f0, _Z_f1; \ | |
155 | doit(_Z_f1, _Z_f0, X##_f, Y##_f); \ | |
156 | /* Normalize since we know where the msb of the multiplicands \ | |
157 | were (bit B), we know that the msb of the of the product is \ | |
158 | at either 2B or 2B-1. */ \ | |
159 | _FP_FRAC_SRS_2(_Z, wfracbits-1, 2*wfracbits); \ | |
160 | R##_f = _Z_f0; \ | |
161 | } while (0) | |
162 | ||
163 | /* Finally, a simple widening multiply algorithm. What fun! */ | |
164 | ||
165 | #define _FP_MUL_MEAT_1_hard(wfracbits, R, X, Y) \ | |
166 | do { \ | |
167 | _FP_W_TYPE _xh, _xl, _yh, _yl, _z_f0, _z_f1, _a_f0, _a_f1; \ | |
168 | \ | |
169 | /* split the words in half */ \ | |
170 | _xh = X##_f >> (_FP_W_TYPE_SIZE/2); \ | |
171 | _xl = X##_f & (((_FP_W_TYPE)1 << (_FP_W_TYPE_SIZE/2)) - 1); \ | |
172 | _yh = Y##_f >> (_FP_W_TYPE_SIZE/2); \ | |
173 | _yl = Y##_f & (((_FP_W_TYPE)1 << (_FP_W_TYPE_SIZE/2)) - 1); \ | |
174 | \ | |
175 | /* multiply the pieces */ \ | |
176 | _z_f0 = _xl * _yl; \ | |
177 | _a_f0 = _xh * _yl; \ | |
178 | _a_f1 = _xl * _yh; \ | |
179 | _z_f1 = _xh * _yh; \ | |
180 | \ | |
181 | /* reassemble into two full words */ \ | |
182 | if ((_a_f0 += _a_f1) < _a_f1) \ | |
183 | _z_f1 += (_FP_W_TYPE)1 << (_FP_W_TYPE_SIZE/2); \ | |
184 | _a_f1 = _a_f0 >> (_FP_W_TYPE_SIZE/2); \ | |
185 | _a_f0 = _a_f0 << (_FP_W_TYPE_SIZE/2); \ | |
186 | _FP_FRAC_ADD_2(_z, _z, _a); \ | |
187 | \ | |
188 | /* normalize */ \ | |
189 | _FP_FRAC_SRS_2(_z, wfracbits - 1, 2*wfracbits); \ | |
190 | R##_f = _z_f0; \ | |
191 | } while (0) | |
192 | ||
193 | ||
194 | /* | |
195 | * Division algorithms: | |
196 | */ | |
197 | ||
198 | /* Basic. Assuming the host word size is >= 2*FRACBITS, we can do the | |
199 | division immediately. Give this macro either _FP_DIV_HELP_imm for | |
200 | C primitives or _FP_DIV_HELP_ldiv for the ISO function. Which you | |
201 | choose will depend on what the compiler does with divrem4. */ | |
202 | ||
203 | #define _FP_DIV_MEAT_1_imm(fs, R, X, Y, doit) \ | |
204 | do { \ | |
205 | _FP_W_TYPE _q, _r; \ | |
206 | X##_f <<= (X##_f < Y##_f \ | |
207 | ? R##_e--, _FP_WFRACBITS_##fs \ | |
208 | : _FP_WFRACBITS_##fs - 1); \ | |
209 | doit(_q, _r, X##_f, Y##_f); \ | |
210 | R##_f = _q | (_r != 0); \ | |
211 | } while (0) | |
212 | ||
213 | /* GCC's longlong.h defines a 2W / 1W => (1W,1W) primitive udiv_qrnnd | |
214 | that may be useful in this situation. This first is for a primitive | |
215 | that requires normalization, the second for one that does not. Look | |
216 | for UDIV_NEEDS_NORMALIZATION to tell which your machine needs. */ | |
217 | ||
218 | #define _FP_DIV_MEAT_1_udiv_norm(fs, R, X, Y) \ | |
219 | do { \ | |
cbc85992 | 220 | _FP_W_TYPE _nh, _nl, _q, _r, _y; \ |
d876f532 UD |
221 | \ |
222 | /* Normalize Y -- i.e. make the most significant bit set. */ \ | |
cbc85992 | 223 | _y = Y##_f << _FP_WFRACXBITS_##fs; \ |
d876f532 UD |
224 | \ |
225 | /* Shift X op correspondingly high, that is, up one full word. */ \ | |
cbc85992 | 226 | if (X##_f < Y##_f) \ |
d876f532 | 227 | { \ |
cbc85992 | 228 | R##_e--; \ |
d876f532 UD |
229 | _nl = 0; \ |
230 | _nh = X##_f; \ | |
231 | } \ | |
232 | else \ | |
233 | { \ | |
cbc85992 | 234 | _nl = X##_f << (_FP_W_TYPE_SIZE - 1); \ |
d876f532 UD |
235 | _nh = X##_f >> 1; \ |
236 | } \ | |
237 | \ | |
cbc85992 | 238 | udiv_qrnnd(_q, _r, _nh, _nl, _y); \ |
d876f532 UD |
239 | R##_f = _q | (_r != 0); \ |
240 | } while (0) | |
241 | ||
242 | #define _FP_DIV_MEAT_1_udiv(fs, R, X, Y) \ | |
243 | do { \ | |
244 | _FP_W_TYPE _nh, _nl, _q, _r; \ | |
245 | if (X##_f < Y##_f) \ | |
246 | { \ | |
247 | R##_e--; \ | |
248 | _nl = X##_f << _FP_WFRACBITS_##fs; \ | |
249 | _nh = X##_f >> _FP_WFRACXBITS_##fs; \ | |
250 | } \ | |
251 | else \ | |
252 | { \ | |
253 | _nl = X##_f << (_FP_WFRACBITS_##fs - 1); \ | |
254 | _nh = X##_f >> (_FP_WFRACXBITS_##fs + 1); \ | |
255 | } \ | |
256 | udiv_qrnnd(_q, _r, _nh, _nl, Y##_f); \ | |
257 | R##_f = _q | (_r != 0); \ | |
258 | } while (0) | |
259 | ||
260 | ||
261 | /* | |
262 | * Square root algorithms: | |
263 | * We have just one right now, maybe Newton approximation | |
264 | * should be added for those machines where division is fast. | |
265 | */ | |
266 | ||
267 | #define _FP_SQRT_MEAT_1(R, S, T, X, q) \ | |
268 | do { \ | |
269 | while (q != _FP_WORK_ROUND) \ | |
270 | { \ | |
271 | T##_f = S##_f + q; \ | |
272 | if (T##_f <= X##_f) \ | |
273 | { \ | |
274 | S##_f = T##_f + q; \ | |
275 | X##_f -= T##_f; \ | |
276 | R##_f += q; \ | |
277 | } \ | |
278 | _FP_FRAC_SLL_1(X, 1); \ | |
279 | q >>= 1; \ | |
280 | } \ | |
281 | if (X##_f) \ | |
282 | { \ | |
283 | if (S##_f < X##_f) \ | |
284 | R##_f |= _FP_WORK_ROUND; \ | |
285 | R##_f |= _FP_WORK_STICKY; \ | |
286 | } \ | |
287 | } while (0) | |
288 | ||
289 | /* | |
290 | * Assembly/disassembly for converting to/from integral types. | |
291 | * No shifting or overflow handled here. | |
292 | */ | |
293 | ||
294 | #define _FP_FRAC_ASSEMBLE_1(r, X, rsize) (r = X##_f) | |
295 | #define _FP_FRAC_DISASSEMBLE_1(X, r, rsize) (X##_f = r) | |
296 | ||
297 | ||
298 | /* | |
299 | * Convert FP values between word sizes | |
300 | */ | |
301 | ||
fe0b1e85 | 302 | #define _FP_FRAC_COPY_1_1(D, S) (D##_f = S##_f) |