1 /* Software floating-point emulation.
2 Copyright (C) 1997-2022 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 In addition to the permissions in the GNU Lesser General Public
11 License, the Free Software Foundation gives you unlimited
12 permission to link the compiled version of this file into
13 combinations with other programs, and to distribute those
14 combinations without any restriction coming from the use of this
15 file. (The Lesser General Public License restrictions do apply in
16 other respects; for example, they cover modification of the file,
17 and distribution when not linked into a combine executable.)
18
19 The GNU C Library is distributed in the hope that it will be useful,
20 but WITHOUT ANY WARRANTY; without even the implied warranty of
21 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
22 Lesser General Public License for more details.
23
24 You should have received a copy of the GNU Lesser General Public
25 License along with the GNU C Library; if not, see
26 <https://www.gnu.org/licenses/>. */
27
28 #ifndef SOFT_FP_H
29 #define SOFT_FP_H 1
30
31 #ifdef _LIBC
32 # include <sfp-machine.h>
33 #elif defined __KERNEL__
34 /* The Linux kernel uses asm/ names for architecture-specific
35 files. */
36 # include <asm/sfp-machine.h>
37 #else
38 # include "sfp-machine.h"
39 #endif
40
41 /* Allow sfp-machine to have its own byte order definitions. */
42 #ifndef __BYTE_ORDER
43 # ifdef _LIBC
44 # include <endian.h>
45 # else
46 # error "endianness not defined by sfp-machine.h"
47 # endif
48 #endif
49
50 /* For unreachable default cases in switch statements over bitwise OR
51 of FP_CLS_* values. */
52 #if (defined __GNUC__ \
53 && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 5)))
54 # define _FP_UNREACHABLE __builtin_unreachable ()
55 #else
56 # define _FP_UNREACHABLE abort ()
57 #endif
58
59 #if ((defined __GNUC__ \
60 && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6))) \
61 || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 201112L))
62 # define _FP_STATIC_ASSERT(expr, msg) \
63 _Static_assert ((expr), msg)
64 #else
65 # define _FP_STATIC_ASSERT(expr, msg) \
66 extern int (*__Static_assert_function (void)) \
67 [!!sizeof (struct { int __error_if_negative: (expr) ? 2 : -1; })]
68 #endif
69
70 /* In the Linux kernel, some architectures have a single function that
71 uses different kinds of unpacking and packing depending on the
72 instruction being emulated, meaning it is not readily visible to
73 the compiler that variables from _FP_DECL and _FP_FRAC_DECL_*
74 macros are only used in cases where they were initialized. */
75 #ifdef __KERNEL__
76 # define _FP_ZERO_INIT = 0
77 #else
78 # define _FP_ZERO_INIT
79 #endif
80
81 #define _FP_WORKBITS 3
82 #define _FP_WORK_LSB ((_FP_W_TYPE) 1 << 3)
83 #define _FP_WORK_ROUND ((_FP_W_TYPE) 1 << 2)
84 #define _FP_WORK_GUARD ((_FP_W_TYPE) 1 << 1)
85 #define _FP_WORK_STICKY ((_FP_W_TYPE) 1 << 0)
86
87 #ifndef FP_RND_NEAREST
88 # define FP_RND_NEAREST 0
89 # define FP_RND_ZERO 1
90 # define FP_RND_PINF 2
91 # define FP_RND_MINF 3
92 #endif
93 #ifndef FP_ROUNDMODE
94 # define FP_ROUNDMODE FP_RND_NEAREST
95 #endif
96
97 /* By default don't care about exceptions. */
98 #ifndef FP_EX_INVALID
99 # define FP_EX_INVALID 0
100 #endif
101 #ifndef FP_EX_OVERFLOW
102 # define FP_EX_OVERFLOW 0
103 #endif
104 #ifndef FP_EX_UNDERFLOW
105 # define FP_EX_UNDERFLOW 0
106 #endif
107 #ifndef FP_EX_DIVZERO
108 # define FP_EX_DIVZERO 0
109 #endif
110 #ifndef FP_EX_INEXACT
111 # define FP_EX_INEXACT 0
112 #endif
113 #ifndef FP_EX_DENORM
114 # define FP_EX_DENORM 0
115 #endif
116
117 /* Sub-exceptions of "invalid". */
118 /* Signaling NaN operand. */
119 #ifndef FP_EX_INVALID_SNAN
120 # define FP_EX_INVALID_SNAN 0
121 #endif
122 /* Inf * 0. */
123 #ifndef FP_EX_INVALID_IMZ
124 # define FP_EX_INVALID_IMZ 0
125 #endif
126 /* fma (Inf, 0, c). */
127 #ifndef FP_EX_INVALID_IMZ_FMA
128 # define FP_EX_INVALID_IMZ_FMA 0
129 #endif
130 /* Inf - Inf. */
131 #ifndef FP_EX_INVALID_ISI
132 # define FP_EX_INVALID_ISI 0
133 #endif
134 /* 0 / 0. */
135 #ifndef FP_EX_INVALID_ZDZ
136 # define FP_EX_INVALID_ZDZ 0
137 #endif
138 /* Inf / Inf. */
139 #ifndef FP_EX_INVALID_IDI
140 # define FP_EX_INVALID_IDI 0
141 #endif
142 /* sqrt (negative). */
143 #ifndef FP_EX_INVALID_SQRT
144 # define FP_EX_INVALID_SQRT 0
145 #endif
146 /* Invalid conversion to integer. */
147 #ifndef FP_EX_INVALID_CVI
148 # define FP_EX_INVALID_CVI 0
149 #endif
150 /* Invalid comparison. */
151 #ifndef FP_EX_INVALID_VC
152 # define FP_EX_INVALID_VC 0
153 #endif
154
155 /* _FP_STRUCT_LAYOUT may be defined as an attribute to determine the
156 struct layout variant used for structures where bit-fields are used
157 to access specific parts of binary floating-point numbers. This is
158 required for systems where the default ABI uses struct layout with
159 differences in how consecutive bit-fields are laid out from the
160 default expected by soft-fp. */
161 #ifndef _FP_STRUCT_LAYOUT
162 # define _FP_STRUCT_LAYOUT
163 #endif
164
165 #ifdef _FP_DECL_EX
166 # define FP_DECL_EX \
167 int _fex = 0; \
168 _FP_DECL_EX
169 #else
170 # define FP_DECL_EX int _fex = 0
171 #endif
172
173 /* Initialize any machine-specific state used in FP_ROUNDMODE,
174 FP_TRAPPING_EXCEPTIONS or FP_HANDLE_EXCEPTIONS. */
175 #ifndef FP_INIT_ROUNDMODE
176 # define FP_INIT_ROUNDMODE do {} while (0)
177 #endif
178
179 /* Initialize any machine-specific state used in
180 FP_TRAPPING_EXCEPTIONS or FP_HANDLE_EXCEPTIONS. */
181 #ifndef FP_INIT_TRAPPING_EXCEPTIONS
182 # define FP_INIT_TRAPPING_EXCEPTIONS FP_INIT_ROUNDMODE
183 #endif
184
185 /* Initialize any machine-specific state used in
186 FP_HANDLE_EXCEPTIONS. */
187 #ifndef FP_INIT_EXCEPTIONS
188 # define FP_INIT_EXCEPTIONS FP_INIT_TRAPPING_EXCEPTIONS
189 #endif
190
191 #ifndef FP_HANDLE_EXCEPTIONS
192 # define FP_HANDLE_EXCEPTIONS do {} while (0)
193 #endif
194
195 /* Whether to flush subnormal inputs to zero with the same sign. */
196 #ifndef FP_DENORM_ZERO
197 # define FP_DENORM_ZERO 0
198 #endif
199
200 #ifndef FP_INHIBIT_RESULTS
201 /* By default we write the results always.
202 sfp-machine may override this and e.g.
203 check if some exceptions are unmasked
204 and inhibit it in such a case. */
205 # define FP_INHIBIT_RESULTS 0
206 #endif
207
208 #define FP_SET_EXCEPTION(ex) \
209 _fex |= (ex)
210
211 #define FP_CUR_EXCEPTIONS \
212 (_fex)
213
214 #ifndef FP_TRAPPING_EXCEPTIONS
215 # define FP_TRAPPING_EXCEPTIONS 0
216 #endif
217
218 /* A file using soft-fp may define FP_NO_EXCEPTIONS before including
219 soft-fp.h to indicate that, although a macro used there could raise
220 exceptions, or do rounding and potentially thereby raise
221 exceptions, for some arguments, for the particular arguments used
222 in that file no exceptions or rounding can occur. Such a file
223 should not itself use macros relating to handling exceptions and
224 rounding modes; this is only for indirect uses (in particular, in
225 _FP_FROM_INT and the macros it calls). */
226 #ifdef FP_NO_EXCEPTIONS
227
228 # undef FP_SET_EXCEPTION
229 # define FP_SET_EXCEPTION(ex) do {} while (0)
230
231 # undef FP_CUR_EXCEPTIONS
232 # define FP_CUR_EXCEPTIONS 0
233
234 # undef FP_TRAPPING_EXCEPTIONS
235 # define FP_TRAPPING_EXCEPTIONS 0
236
237 # undef FP_ROUNDMODE
238 # define FP_ROUNDMODE FP_RND_ZERO
239
240 # undef _FP_TININESS_AFTER_ROUNDING
241 # define _FP_TININESS_AFTER_ROUNDING 0
242
243 #endif
244
245 /* A file using soft-fp may define FP_NO_EXACT_UNDERFLOW before
246 including soft-fp.h to indicate that, although a macro used there
247 could allow for the case of exact underflow requiring the underflow
248 exception to be raised if traps are enabled, for the particular
249 arguments used in that file no exact underflow can occur. */
250 #ifdef FP_NO_EXACT_UNDERFLOW
251 # undef FP_TRAPPING_EXCEPTIONS
252 # define FP_TRAPPING_EXCEPTIONS 0
253 #endif
254
255 #define _FP_ROUND_NEAREST(wc, X) \
256 do \
257 { \
258 if ((_FP_FRAC_LOW_##wc (X) & 15) != _FP_WORK_ROUND) \
259 _FP_FRAC_ADDI_##wc (X, _FP_WORK_ROUND); \
260 } \
261 while (0)
262
263 #define _FP_ROUND_ZERO(wc, X) (void) 0
264
265 #define _FP_ROUND_PINF(wc, X) \
266 do \
267 { \
268 if (!X##_s && (_FP_FRAC_LOW_##wc (X) & 7)) \
269 _FP_FRAC_ADDI_##wc (X, _FP_WORK_LSB); \
270 } \
271 while (0)
272
273 #define _FP_ROUND_MINF(wc, X) \
274 do \
275 { \
276 if (X##_s && (_FP_FRAC_LOW_##wc (X) & 7)) \
277 _FP_FRAC_ADDI_##wc (X, _FP_WORK_LSB); \
278 } \
279 while (0)
280
281 #define _FP_ROUND(wc, X) \
282 do \
283 { \
284 if (_FP_FRAC_LOW_##wc (X) & 7) \
285 { \
286 FP_SET_EXCEPTION (FP_EX_INEXACT); \
287 switch (FP_ROUNDMODE) \
288 { \
289 case FP_RND_NEAREST: \
290 _FP_ROUND_NEAREST (wc, X); \
291 break; \
292 case FP_RND_ZERO: \
293 _FP_ROUND_ZERO (wc, X); \
294 break; \
295 case FP_RND_PINF: \
296 _FP_ROUND_PINF (wc, X); \
297 break; \
298 case FP_RND_MINF: \
299 _FP_ROUND_MINF (wc, X); \
300 break; \
301 } \
302 } \
303 } \
304 while (0)
305
306 #define FP_CLS_NORMAL 0
307 #define FP_CLS_ZERO 1
308 #define FP_CLS_INF 2
309 #define FP_CLS_NAN 3
310
311 #define _FP_CLS_COMBINE(x, y) (((x) << 2) | (y))
312
313 #include "op-1.h"
314 #include "op-2.h"
315 #include "op-4.h"
316 #include "op-8.h"
317 #include "op-common.h"
318
319 /* Sigh. Silly things longlong.h needs. */
320 #define UWtype _FP_W_TYPE
321 #define W_TYPE_SIZE _FP_W_TYPE_SIZE
322
323 typedef int QItype __attribute__ ((mode (QI)));
324 typedef int SItype __attribute__ ((mode (SI)));
325 typedef int DItype __attribute__ ((mode (DI)));
326 typedef unsigned int UQItype __attribute__ ((mode (QI)));
327 typedef unsigned int USItype __attribute__ ((mode (SI)));
328 typedef unsigned int UDItype __attribute__ ((mode (DI)));
329 #if _FP_W_TYPE_SIZE == 32
330 typedef unsigned int UHWtype __attribute__ ((mode (HI)));
331 #elif _FP_W_TYPE_SIZE == 64
332 typedef USItype UHWtype;
333 #endif
334
335 #ifndef CMPtype
336 # define CMPtype int
337 #endif
338
339 #define SI_BITS (__CHAR_BIT__ * (int) sizeof (SItype))
340 #define DI_BITS (__CHAR_BIT__ * (int) sizeof (DItype))
341
342 #ifndef umul_ppmm
343 # ifdef _LIBC
344 # include <stdlib/longlong.h>
345 # else
346 # include "longlong.h"
347 # endif
348 #endif
349
350 #endif /* !SOFT_FP_H */