summaryrefslogtreecommitdiff
path: root/Zend/zend_float.h
blob: d0258e4c1a86b0c48f43102c4ad65db0f30ef164 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
/*
   +----------------------------------------------------------------------+
   | Zend Engine                                                          |
   +----------------------------------------------------------------------+
   | Copyright (c) 1998-2017 Zend Technologies Ltd. (http://www.zend.com) |
   +----------------------------------------------------------------------+
   | This source file is subject to version 2.00 of the Zend license,     |
   | that is bundled with this package in the file LICENSE, and is        |
   | available through the world-wide-web at the following url:           |
   | http://www.zend.com/license/2_00.txt.                                |
   | If you did not receive a copy of the Zend license and are unable to  |
   | obtain it through the world-wide-web, please send a note to          |
   | license@zend.com so we can mail you a copy immediately.              |
   +----------------------------------------------------------------------+
   | Authors: Christian Seiler <chris_se@gmx.net>                         |
   +----------------------------------------------------------------------+
*/

/* $Id$ */

#ifndef ZEND_FLOAT_H
#define ZEND_FLOAT_H

BEGIN_EXTERN_C()

/*
  Define functions for FP initialization and de-initialization.
*/
extern ZEND_API void zend_init_fpu(void);
extern ZEND_API void zend_shutdown_fpu(void);
extern ZEND_API void zend_ensure_fpu_mode(void);

END_EXTERN_C()

/* Copy of the contents of xpfpa.h (which is under public domain)
   See http://wiki.php.net/rfc/rounding for details.

   Cross Platform Floating Point Arithmetics

   This header file defines several platform-dependent macros that ensure
   equal and deterministic floating point behaviour across several platforms,
   compilers and architectures.

   The current macros are currently only used on x86 and x86_64 architectures,
   on every other architecture, these macros expand to NOPs. This assumes that
   other architectures do not have an internal precision and the operhand types
   define the computational precision of floating point operations. This
   assumption may be false, in that case, the author is interested in further
   details on the other platform.

   For further details, please visit:
   http://www.christian-seiler.de/projekte/fpmath/

   Version: 20090317 */

/*
 Implementation notes:

 x86_64:
  - Since all x86_64 compilers use SSE by default, it is probably unnecessary
    to use these macros there. We define them anyway since we are too lazy
    to differentiate the architecture. Also, the compiler option -mfpmath=i387
    justifies this decision.

 General:
  - It would be nice if one could detect whether SSE if used for math via some
    funky compiler defines and if so, make the macros go to NOPs. Any ideas
    on how to do that?

 MS Visual C:
  - Since MSVC users tipically don't use autoconf or CMake, we will detect
    MSVC via compile time define. Floating point precision change isn't
    supported on 64 bit platforms, so it's NOP. See
    http://msdn.microsoft.com/en-us/library/c9676k6h(v=vs.110).aspx
*/

/* MSVC detection (MSVC people usually don't use autoconf) */
#if defined(_MSC_VER) && !defined(_WIN64)
#  define HAVE__CONTROLFP_S
#endif /* _MSC_VER */

#ifdef HAVE__CONTROLFP_S

/* float.h defines _controlfp_s */
# include <float.h>

# define XPFPA_HAVE_CW 1
# define XPFPA_CW_DATATYPE \
            unsigned int

# define XPFPA_STORE_CW(vptr) do { \
            _controlfp_s((unsigned int *)(vptr), 0, 0); \
        } while (0)

# define XPFPA_RESTORE_CW(vptr) do { \
            unsigned int _xpfpa_fpu_cw; \
            _controlfp_s(&_xpfpa_fpu_cw, *((unsigned int *)(vptr)), _MCW_PC); \
        } while (0)

# define XPFPA_DECLARE \
            unsigned int _xpfpa_fpu_oldcw, _xpfpa_fpu_cw;

# define XPFPA_SWITCH_DOUBLE() do { \
            _controlfp_s(&_xpfpa_fpu_cw, 0, 0); \
            _xpfpa_fpu_oldcw = _xpfpa_fpu_cw; \
            _controlfp_s(&_xpfpa_fpu_cw, _PC_53, _MCW_PC); \
        } while (0)
# define XPFPA_SWITCH_SINGLE() do { \
            _controlfp_s(&_xpfpa_fpu_cw, 0, 0); \
            _xpfpa_fpu_oldcw = _xpfpa_fpu_cw; \
            _controlfp_s(&_xpfpa_fpu_cw, _PC_24, _MCW_PC); \
        } while (0)
/* NOTE: This only sets internal precision. MSVC does NOT support double-
   extended precision! */
# define XPFPA_SWITCH_DOUBLE_EXTENDED() do { \
            _controlfp_s(&_xpfpa_fpu_cw, 0, 0); \
            _xpfpa_fpu_oldcw = _xpfpa_fpu_cw; \
            _controlfp_s(&_xpfpa_fpu_cw, _PC_64, _MCW_PC); \
        } while (0)
# define XPFPA_RESTORE() \
            _controlfp_s(&_xpfpa_fpu_cw, _xpfpa_fpu_oldcw, _MCW_PC)
/* We do NOT use the volatile return trick since _controlfp_s is a function
   call and thus FP registers are saved in memory anyway. However, we do use
   a variable to ensure that the expression passed into val will be evaluated
   *before* switching back contexts. */
# define XPFPA_RETURN_DOUBLE(val) \
            do { \
                double _xpfpa_result = (val); \
                XPFPA_RESTORE(); \
                return _xpfpa_result; \
            } while (0)
# define XPFPA_RETURN_SINGLE(val) \
            do { \
                float _xpfpa_result = (val); \
                XPFPA_RESTORE(); \
                return _xpfpa_result; \
            } while (0)
/* This won't work, but we add a macro for it anyway. */
# define XPFPA_RETURN_DOUBLE_EXTENDED(val) \
            do { \
                long double _xpfpa_result = (val); \
                XPFPA_RESTORE(); \
                return _xpfpa_result; \
            } while (0)

#elif defined(HAVE__CONTROLFP)

/* float.h defines _controlfp */
# include <float.h>

# define XPFPA_DECLARE \
            unsigned int _xpfpa_fpu_oldcw;

# define XPFPA_HAVE_CW 1
# define XPFPA_CW_DATATYPE \
            unsigned int

# define XPFPA_STORE_CW(vptr) do { \
            *((unsigned int *)(vptr)) = _controlfp(0, 0); \
        } while (0)

# define XPFPA_RESTORE_CW(vptr) do { \
            _controlfp(*((unsigned int *)(vptr)), _MCW_PC); \
        } while (0)

# define XPFPA_SWITCH_DOUBLE() do { \
            _xpfpa_fpu_oldcw = _controlfp(0, 0); \
            _controlfp(_PC_53, _MCW_PC); \
        } while (0)
# define XPFPA_SWITCH_SINGLE() do { \
            _xpfpa_fpu_oldcw = _controlfp(0, 0); \
            _controlfp(_PC_24, _MCW_PC); \
        } while (0)
/* NOTE: This will only work as expected on MinGW. */
# define XPFPA_SWITCH_DOUBLE_EXTENDED() do { \
            _xpfpa_fpu_oldcw = _controlfp(0, 0); \
            _controlfp(_PC_64, _MCW_PC); \
        } while (0)
# define XPFPA_RESTORE() \
            _controlfp(_xpfpa_fpu_oldcw, _MCW_PC)
/* We do NOT use the volatile return trick since _controlfp is a function
   call and thus FP registers are saved in memory anyway. However, we do use
   a variable to ensure that the expression passed into val will be evaluated
   *before* switching back contexts. */
# define XPFPA_RETURN_DOUBLE(val) \
            do { \
                double _xpfpa_result = (val); \
                XPFPA_RESTORE(); \
                return _xpfpa_result; \
            } while (0)
# define XPFPA_RETURN_SINGLE(val) \
            do { \
                float _xpfpa_result = (val); \
                XPFPA_RESTORE(); \
                return _xpfpa_result; \
            } while (0)
/* This will only work on MinGW */
# define XPFPA_RETURN_DOUBLE_EXTENDED(val) \
            do { \
                long double _xpfpa_result = (val); \
                XPFPA_RESTORE(); \
                return _xpfpa_result; \
            } while (0)

#elif defined(HAVE__FPU_SETCW) /* glibc systems */

/* fpu_control.h defines _FPU_[GS]ETCW */
# include <fpu_control.h>

# define XPFPA_DECLARE \
            fpu_control_t _xpfpa_fpu_oldcw, _xpfpa_fpu_cw;

# define XPFPA_HAVE_CW 1
# define XPFPA_CW_DATATYPE \
            fpu_control_t

# define XPFPA_STORE_CW(vptr) do { \
            _FPU_GETCW((*((fpu_control_t *)(vptr)))); \
        } while (0)

# define XPFPA_RESTORE_CW(vptr) do { \
            _FPU_SETCW((*((fpu_control_t *)(vptr)))); \
        } while (0)

# define XPFPA_SWITCH_DOUBLE() do { \
            _FPU_GETCW(_xpfpa_fpu_oldcw); \
            _xpfpa_fpu_cw = (_xpfpa_fpu_oldcw & ~_FPU_EXTENDED & ~_FPU_SINGLE) | _FPU_DOUBLE; \
            _FPU_SETCW(_xpfpa_fpu_cw); \
        } while (0)
# define XPFPA_SWITCH_SINGLE() do { \
            _FPU_GETCW(_xpfpa_fpu_oldcw); \
            _xpfpa_fpu_cw = (_xpfpa_fpu_oldcw & ~_FPU_EXTENDED & ~_FPU_DOUBLE) | _FPU_SINGLE; \
            _FPU_SETCW(_xpfpa_fpu_cw); \
        } while (0)
# define XPFPA_SWITCH_DOUBLE_EXTENDED()  do { \
            _FPU_GETCW(_xpfpa_fpu_oldcw); \
            _xpfpa_fpu_cw = (_xpfpa_fpu_oldcw & ~_FPU_SINGLE & ~_FPU_DOUBLE) | _FPU_EXTENDED; \
            _FPU_SETCW(_xpfpa_fpu_cw); \
        } while (0)
# define XPFPA_RESTORE() \
            _FPU_SETCW(_xpfpa_fpu_oldcw)
/* We use a temporary volatile variable (in a new block) in order to ensure
   that the optimizer does not mis-optimize the instructions. Also, a volatile
   variable ensures truncation to correct precision. */
# define XPFPA_RETURN_DOUBLE(val) \
            do { \
                volatile double _xpfpa_result = (val); \
                XPFPA_RESTORE(); \
                return _xpfpa_result; \
            } while (0)
# define XPFPA_RETURN_SINGLE(val) \
            do { \
                volatile float _xpfpa_result = (val); \
                XPFPA_RESTORE(); \
                return _xpfpa_result; \
            } while (0)
# define XPFPA_RETURN_DOUBLE_EXTENDED(val) \
            do { \
                volatile long double _xpfpa_result = (val); \
                XPFPA_RESTORE(); \
                return _xpfpa_result; \
            } while (0)

#elif defined(HAVE_FPSETPREC) /* FreeBSD */

/* fpu_control.h defines _FPU_[GS]ETCW */
# include <machine/ieeefp.h>

# define XPFPA_DECLARE \
            fp_prec_t _xpfpa_fpu_oldprec;

# define XPFPA_HAVE_CW 1
# define XPFPA_CW_DATATYPE \
            fp_prec_t

# define XPFPA_STORE_CW(vptr) do { \
            *((fp_prec_t *)(vptr)) = fpgetprec(); \
        } while (0)

# define XPFPA_RESTORE_CW(vptr) do { \
            fpsetprec(*((fp_prec_t *)(vptr))); \
        } while (0)

# define XPFPA_SWITCH_DOUBLE() do { \
            _xpfpa_fpu_oldprec = fpgetprec(); \
            fpsetprec(FP_PD); \
        } while (0)
# define XPFPA_SWITCH_SINGLE() do { \
            _xpfpa_fpu_oldprec = fpgetprec(); \
            fpsetprec(FP_PS); \
        } while (0)
# define XPFPA_SWITCH_DOUBLE_EXTENDED() do { \
            _xpfpa_fpu_oldprec = fpgetprec(); \
            fpsetprec(FP_PE); \
        } while (0)
# define XPFPA_RESTORE() \
            fpsetprec(_xpfpa_fpu_oldprec)
/* We use a temporary volatile variable (in a new block) in order to ensure
   that the optimizer does not mis-optimize the instructions. Also, a volatile
   variable ensures truncation to correct precision. */
# define XPFPA_RETURN_DOUBLE(val) \
            do { \
                volatile double _xpfpa_result = (val); \
                XPFPA_RESTORE(); \
                return _xpfpa_result; \
            } while (0)
# define XPFPA_RETURN_SINGLE(val) \
            do { \
                volatile float _xpfpa_result = (val); \
                XPFPA_RESTORE(); \
                return _xpfpa_result; \
            } while (0)
# define XPFPA_RETURN_DOUBLE_EXTENDED(val) \
            do { \
                volatile long double _xpfpa_result = (val); \
                XPFPA_RESTORE(); \
                return _xpfpa_result; \
            } while (0)

#elif defined(HAVE_FPU_INLINE_ASM_X86)

/*
  Custom x86 inline assembler implementation.

  This implementation does not use predefined wrappers of the OS / compiler
  but rather uses x86/x87 inline assembler directly. Basic instructions:

  fnstcw - Store the FPU control word in a variable
  fldcw  - Load the FPU control word from a variable

  Bits (only bits 8 and 9 are relevant, bits 0 to 7 are for other things):
     0x0yy: Single precision
     0x1yy: Reserved
     0x2yy: Double precision
     0x3yy: Double-extended precision

  We use an unsigned int for the datatype. glibc sources add __mode__ (__HI__)
  attribute to it (HI stands for half-integer according to docs). It is unclear
  what the does exactly and how portable it is.

  The assembly syntax works with GNU CC, Intel CC and Sun CC.
*/

# define XPFPA_DECLARE \
            unsigned int _xpfpa_fpu_oldcw, _xpfpa_fpu_cw;

# define XPFPA_HAVE_CW 1
# define XPFPA_CW_DATATYPE \
            unsigned int

# define XPFPA_STORE_CW(vptr) do { \
            __asm__ __volatile__ ("fnstcw %0" : "=m" (*((unsigned int *)(vptr)))); \
        } while (0)

# define XPFPA_RESTORE_CW(vptr) do { \
            __asm__ __volatile__ ("fldcw %0" : : "m" (*((unsigned int *)(vptr)))); \
        } while (0)

# define XPFPA_SWITCH_DOUBLE() do { \
            __asm__ __volatile__ ("fnstcw %0" : "=m" (*&_xpfpa_fpu_oldcw)); \
            _xpfpa_fpu_cw = (_xpfpa_fpu_oldcw & ~0x100) | 0x200; \
            __asm__ __volatile__ ("fldcw %0" : : "m" (*&_xpfpa_fpu_cw)); \
        } while (0)
# define XPFPA_SWITCH_SINGLE() do { \
            __asm__ __volatile__ ("fnstcw %0" : "=m" (*&_xpfpa_fpu_oldcw)); \
            _xpfpa_fpu_cw = (_xpfpa_fpu_oldcw & ~0x300); \
            __asm__ __volatile__ ("fldcw %0" : : "m" (*&_xpfpa_fpu_cw)); \
        } while (0)
# define XPFPA_SWITCH_DOUBLE_EXTENDED() do { \
            __asm__ __volatile__ ("fnstcw %0" : "=m" (*&_xpfpa_fpu_oldcw)); \
            _xpfpa_fpu_cw = _xpfpa_fpu_oldcw | 0x300; \
            __asm__ __volatile__ ("fldcw %0" : : "m" (*&_xpfpa_fpu_cw)); \
        } while (0)
# define XPFPA_RESTORE() \
            __asm__ __volatile__ ("fldcw %0" : : "m" (*&_xpfpa_fpu_oldcw))
/* We use a temporary volatile variable (in a new block) in order to ensure
   that the optimizer does not mis-optimize the instructions. Also, a volatile
   variable ensures truncation to correct precision. */
# define XPFPA_RETURN_DOUBLE(val) \
            do { \
                volatile double _xpfpa_result = (val); \
                XPFPA_RESTORE(); \
                return _xpfpa_result; \
            } while (0)
# define XPFPA_RETURN_SINGLE(val) \
            do { \
                volatile float _xpfpa_result = (val); \
                XPFPA_RESTORE(); \
                return _xpfpa_result; \
            } while (0)
# define XPFPA_RETURN_DOUBLE_EXTENDED(val) \
            do { \
                volatile long double _xpfpa_result = (val); \
                XPFPA_RESTORE(); \
                return _xpfpa_result; \
            } while (0)

#else /* FPU CONTROL */

/*
  This is either not an x87 FPU or the inline assembly syntax was not
  recognized. In any case, default to NOPs for the macros and hope the
  generated code will behave as planned.
*/
# define XPFPA_DECLARE                      /* NOP */
# define XPFPA_HAVE_CW                      0
# define XPFPA_CW_DATATYPE                  unsigned int
# define XPFPA_STORE_CW(variable)           /* NOP */
# define XPFPA_RESTORE_CW(variable)         /* NOP */
# define XPFPA_SWITCH_DOUBLE()              /* NOP */
# define XPFPA_SWITCH_SINGLE()              /* NOP */
# define XPFPA_SWITCH_DOUBLE_EXTENDED()     /* NOP */
# define XPFPA_RESTORE()                    /* NOP */
# define XPFPA_RETURN_DOUBLE(val)           return (val)
# define XPFPA_RETURN_SINGLE(val)           return (val)
# define XPFPA_RETURN_DOUBLE_EXTENDED(val)  return (val)

#endif /* FPU CONTROL */

#endif

/*
 * Local variables:
 * tab-width: 4
 * c-basic-offset: 4
 * indent-tabs-mode: t
 * End:
 * vim600: sw=4 ts=4 fdm=marker
 * vim<600: sw=4 ts=4
 */