1 /* Software floating-point emulation.
2 Basic one-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),
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
11 modify it under the terms of the GNU Library General Public License as
12 published by the Free Software Foundation; either version 2 of the
13 License, or (at your option) any later version.
14
15 The GNU C Library is distributed in the hope that it will be useful,
16 but WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 Library General Public License for more details.
19
20 You should have received a copy of the GNU Library General Public
21 License along with the GNU C Library; see the file COPYING.LIB. If
22 not, write to the Free Software Foundation, Inc.,
23 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
24
25 #ifndef __MATH_EMU_OP_1_H__
26 #define __MATH_EMU_OP_1_H__
27
28 #define _FP_FRAC_DECL_1(X) _FP_W_TYPE X##_f=0
29 #define _FP_FRAC_COPY_1(D,S) (D##_f = S##_f)
30 #define _FP_FRAC_SET_1(X,I) (X##_f = I)
31 #define _FP_FRAC_HIGH_1(X) (X##_f)
32 #define _FP_FRAC_LOW_1(X) (X##_f)
33 #define _FP_FRAC_WORD_1(X,w) (X##_f)
34
35 #define _FP_FRAC_ADDI_1(X,I) (X##_f += I)
36 #define _FP_FRAC_SLL_1(X,N) \
37 do { \
38 if (__builtin_constant_p(N) && (N) == 1) \
39 X##_f += X##_f; \
40 else \
41 X##_f <<= (N); \
42 } while (0)
43 #define _FP_FRAC_SRL_1(X,N) (X##_f >>= N)
44
45 /* Right shift with sticky-lsb. */
46 #define _FP_FRAC_SRS_1(X,N,sz) __FP_FRAC_SRS_1(X##_f, N, sz)
47
48 #define __FP_FRAC_SRS_1(X,N,sz) \
49 (X = (X >> (N) | (__builtin_constant_p(N) && (N) == 1 \
50 ? X & 1 : (X << (_FP_W_TYPE_SIZE - (N))) != 0)))
51
52 #define _FP_FRAC_ADD_1(R,X,Y) (R##_f = X##_f + Y##_f)
53 #define _FP_FRAC_SUB_1(R,X,Y) (R##_f = X##_f - Y##_f)
54 #define _FP_FRAC_DEC_1(X,Y) (X##_f -= Y##_f)
55 #define _FP_FRAC_CLZ_1(z, X) __FP_CLZ(z, X##_f)
56
57 /* Predicates */
58 #define _FP_FRAC_NEGP_1(X) ((_FP_WS_TYPE)X##_f < 0)
59 #define _FP_FRAC_ZEROP_1(X) (X##_f == 0)
60 #define _FP_FRAC_OVERP_1(fs,X) (X##_f & _FP_OVERFLOW_##fs)
61 #define _FP_FRAC_CLEAR_OVERP_1(fs,X) (X##_f &= ~_FP_OVERFLOW_##fs)
62 #define _FP_FRAC_EQ_1(X, Y) (X##_f == Y##_f)
63 #define _FP_FRAC_GE_1(X, Y) (X##_f >= Y##_f)
64 #define _FP_FRAC_GT_1(X, Y) (X##_f > Y##_f)
65
66 #define _FP_ZEROFRAC_1 0
67 #define _FP_MINFRAC_1 1
68 #define _FP_MAXFRAC_1 (~(_FP_WS_TYPE)0)
69
70 /*
71 * Unpack the raw bits of a native fp value. Do not classify or
72 * normalize the data.
73 */
74
75 #define _FP_UNPACK_RAW_1(fs, X, val) \
76 do { \
77 union _FP_UNION_##fs _flo; _flo.flt = (val); \
78 \
79 X##_f = _flo.bits.frac; \
80 X##_e = _flo.bits.exp; \
81 X##_s = _flo.bits.sign; \
82 } while (0)
83
84 #define _FP_UNPACK_RAW_1_P(fs, X, val) \
85 do { \
86 union _FP_UNION_##fs *_flo = \
87 (union _FP_UNION_##fs *)(val); \
88 \
89 X##_f = _flo->bits.frac; \
90 X##_e = _flo->bits.exp; \
91 X##_s = _flo->bits.sign; \
92 } while (0)
93
94 /*
95 * Repack the raw bits of a native fp value.
96 */
97
98 #define _FP_PACK_RAW_1(fs, val, X) \
99 do { \
100 union _FP_UNION_##fs _flo; \
101 \
102 _flo.bits.frac = X##_f; \
103 _flo.bits.exp = X##_e; \
104 _flo.bits.sign = X##_s; \
105 \
106 (val) = _flo.flt; \
107 } while (0)
108
109 #define _FP_PACK_RAW_1_P(fs, val, X) \
110 do { \
111 union _FP_UNION_##fs *_flo = \
112 (union _FP_UNION_##fs *)(val); \
113 \
114 _flo->bits.frac = X##_f; \
115 _flo->bits.exp = X##_e; \
116 _flo->bits.sign = X##_s; \
117 } while (0)
118
119
120 /*
121 * Multiplication algorithms:
122 */
123
124 /* Basic. Assuming the host word size is >= 2*FRACBITS, we can do the
125 multiplication immediately. */
126
127 #define _FP_MUL_MEAT_1_imm(wfracbits, R, X, Y) \
128 do { \
129 R##_f = X##_f * Y##_f; \
130 /* Normalize since we know where the msb of the multiplicands \
131 were (bit B), we know that the msb of the of the product is \
132 at either 2B or 2B-1. */ \
133 _FP_FRAC_SRS_1(R, wfracbits-1, 2*wfracbits); \
134 } while (0)
135
136 /* Given a 1W * 1W => 2W primitive, do the extended multiplication. */
137
138 #define _FP_MUL_MEAT_1_wide(wfracbits, R, X, Y, doit) \
139 do { \
140 _FP_W_TYPE _Z_f0, _Z_f1; \
141 doit(_Z_f1, _Z_f0, X##_f, Y##_f); \
142 /* Normalize since we know where the msb of the multiplicands \
143 were (bit B), we know that the msb of the of the product is \
144 at either 2B or 2B-1. */ \
145 _FP_FRAC_SRS_2(_Z, wfracbits-1, 2*wfracbits); \
146 R##_f = _Z_f0; \
147 } while (0)
148
149 /* Finally, a simple widening multiply algorithm. What fun! */
150
151 #define _FP_MUL_MEAT_1_hard(wfracbits, R, X, Y) \
152 do { \
153 _FP_W_TYPE _xh, _xl, _yh, _yl, _z_f0, _z_f1, _a_f0, _a_f1; \
154 \
155 /* split the words in half */ \
156 _xh = X##_f >> (_FP_W_TYPE_SIZE/2); \
157 _xl = X##_f & (((_FP_W_TYPE)1 << (_FP_W_TYPE_SIZE/2)) - 1); \
158 _yh = Y##_f >> (_FP_W_TYPE_SIZE/2); \
159 _yl = Y##_f & (((_FP_W_TYPE)1 << (_FP_W_TYPE_SIZE/2)) - 1); \
160 \
161 /* multiply the pieces */ \
162 _z_f0 = _xl * _yl; \
163 _a_f0 = _xh * _yl; \
164 _a_f1 = _xl * _yh; \
165 _z_f1 = _xh * _yh; \
166 \
167 /* reassemble into two full words */ \
168 if ((_a_f0 += _a_f1) < _a_f1) \
169 _z_f1 += (_FP_W_TYPE)1 << (_FP_W_TYPE_SIZE/2); \
170 _a_f1 = _a_f0 >> (_FP_W_TYPE_SIZE/2); \
171 _a_f0 = _a_f0 << (_FP_W_TYPE_SIZE/2); \
172 _FP_FRAC_ADD_2(_z, _z, _a); \
173 \
174 /* normalize */ \
175 _FP_FRAC_SRS_2(_z, wfracbits - 1, 2*wfracbits); \
176 R##_f = _z_f0; \
177 } while (0)
178
179
180 /*
181 * Division algorithms:
182 */
183
184 /* Basic. Assuming the host word size is >= 2*FRACBITS, we can do the
185 division immediately. Give this macro either _FP_DIV_HELP_imm for
186 C primitives or _FP_DIV_HELP_ldiv for the ISO function. Which you
187 choose will depend on what the compiler does with divrem4. */
188
189 #define _FP_DIV_MEAT_1_imm(fs, R, X, Y, doit) \
190 do { \
191 _FP_W_TYPE _q, _r; \
192 X##_f <<= (X##_f < Y##_f \
193 ? R##_e--, _FP_WFRACBITS_##fs \
194 : _FP_WFRACBITS_##fs - 1); \
195 doit(_q, _r, X##_f, Y##_f); \
196 R##_f = _q | (_r != 0); \
197 } while (0)
198
199 /* GCC's longlong.h defines a 2W / 1W => (1W,1W) primitive udiv_qrnnd
200 that may be useful in this situation. This first is for a primitive
201 that requires normalization, the second for one that does not. Look
202 for UDIV_NEEDS_NORMALIZATION to tell which your machine needs. */
203
204 #define _FP_DIV_MEAT_1_udiv_norm(fs, R, X, Y) \
205 do { \
206 _FP_W_TYPE _nh, _nl, _q, _r, _y; \
207 \
208 /* Normalize Y -- i.e. make the most significant bit set. */ \
209 _y = Y##_f << _FP_WFRACXBITS_##fs; \
210 \
211 /* Shift X op correspondingly high, that is, up one full word. */ \
212 if (X##_f < Y##_f) \
213 { \
214 R##_e--; \
215 _nl = 0; \
216 _nh = X##_f; \
217 } \
218 else \
219 { \
220 _nl = X##_f << (_FP_W_TYPE_SIZE - 1); \
221 _nh = X##_f >> 1; \
222 } \
223 \
224 udiv_qrnnd(_q, _r, _nh, _nl, _y); \
225 R##_f = _q | (_r != 0); \
226 } while (0)
227
228 #define _FP_DIV_MEAT_1_udiv(fs, R, X, Y) \
229 do { \
230 _FP_W_TYPE _nh, _nl, _q, _r; \
231 if (X##_f < Y##_f) \
232 { \
233 R##_e--; \
234 _nl = X##_f << _FP_WFRACBITS_##fs; \
235 _nh = X##_f >> _FP_WFRACXBITS_##fs; \
236 } \
237 else \
238 { \
239 _nl = X##_f << (_FP_WFRACBITS_##fs - 1); \
240 _nh = X##_f >> (_FP_WFRACXBITS_##fs + 1); \
241 } \
242 udiv_qrnnd(_q, _r, _nh, _nl, Y##_f); \
243 R##_f = _q | (_r != 0); \
244 } while (0)
245
246
247 /*
248 * Square root algorithms:
249 * We have just one right now, maybe Newton approximation
250 * should be added for those machines where division is fast.
251 */
252
253 #define _FP_SQRT_MEAT_1(R, S, T, X, q) \
254 do { \
255 while (q != _FP_WORK_ROUND) \
256 { \
257 T##_f = S##_f + q; \
258 if (T##_f <= X##_f) \
259 { \
260 S##_f = T##_f + q; \
261 X##_f -= T##_f; \
262 R##_f += q; \
263 } \
264 _FP_FRAC_SLL_1(X, 1); \
265 q >>= 1; \
266 } \
267 if (X##_f) \
268 { \
269 if (S##_f < X##_f) \
270 R##_f |= _FP_WORK_ROUND; \
271 R##_f |= _FP_WORK_STICKY; \
272 } \
273 } while (0)
274
275 /*
276 * Assembly/disassembly for converting to/from integral types.
277 * No shifting or overflow handled here.
278 */
279
280 #define _FP_FRAC_ASSEMBLE_1(r, X, rsize) (r = X##_f)
281 #define _FP_FRAC_DISASSEMBLE_1(X, r, rsize) (X##_f = r)
282
283
284 /*
285 * Convert FP values between word sizes
286 */
287
288 #define _FP_FRAC_CONV_1_1(dfs, sfs, D, S) \
289 do { \
290 D##_f = S##_f; \
291 if (_FP_WFRACBITS_##sfs > _FP_WFRACBITS_##dfs) \
292 { \
293 if (S##_c != FP_CLS_NAN) \
294 _FP_FRAC_SRS_1(D, (_FP_WFRACBITS_##sfs-_FP_WFRACBITS_##dfs), \
295 _FP_WFRACBITS_##sfs); \
296 else \
297 _FP_FRAC_SRL_1(D, (_FP_WFRACBITS_##sfs-_FP_WFRACBITS_##dfs)); \
298 } \
299 else \
300 D##_f <<= _FP_WFRACBITS_##dfs - _FP_WFRACBITS_##sfs; \
301 } while (0)
302
303 #endif /* __MATH_EMU_OP_1_H__ */