1/* Definitions of floating-point access for GNU compiler.
2   Copyright (C) 1989-2013 Free Software Foundation, Inc.
3
4   This file is part of GCC.
5
6   GCC is free software; you can redistribute it and/or modify it under
7   the terms of the GNU General Public License as published by the Free
8   Software Foundation; either version 3, or (at your option) any later
9   version.
10
11   GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12   WARRANTY; without even the implied warranty of MERCHANTABILITY or
13   FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14   for more details.
15
16   You should have received a copy of the GNU General Public License
17   along with GCC; see the file COPYING3.  If not see
18   <http://www.gnu.org/licenses/>.  */
19
20#ifndef GCC_REAL_H
21#define GCC_REAL_H
22
23#include "machmode.h"
24
25/* An expanded form of the represented number.  */
26
27/* Enumerate the special cases of numbers that we encounter.  */
28enum real_value_class {
29  rvc_zero,
30  rvc_normal,
31  rvc_inf,
32  rvc_nan
33};
34
35#define SIGNIFICAND_BITS	(128 + HOST_BITS_PER_LONG)
36#define EXP_BITS		(32 - 6)
37#define MAX_EXP			((1 << (EXP_BITS - 1)) - 1)
38#define SIGSZ			(SIGNIFICAND_BITS / HOST_BITS_PER_LONG)
39#define SIG_MSB			((unsigned long)1 << (HOST_BITS_PER_LONG - 1))
40
41struct GTY(()) real_value {
42  /* Use the same underlying type for all bit-fields, so as to make
43     sure they're packed together, otherwise REAL_VALUE_TYPE_SIZE will
44     be miscomputed.  */
45  unsigned int /* ENUM_BITFIELD (real_value_class) */ cl : 2;
46  unsigned int decimal : 1;
47  unsigned int sign : 1;
48  unsigned int signalling : 1;
49  unsigned int canonical : 1;
50  unsigned int uexp : EXP_BITS;
51  unsigned long sig[SIGSZ];
52};
53
54#define REAL_EXP(REAL) \
55  ((int)((REAL)->uexp ^ (unsigned int)(1 << (EXP_BITS - 1))) \
56   - (1 << (EXP_BITS - 1)))
57#define SET_REAL_EXP(REAL, EXP) \
58  ((REAL)->uexp = ((unsigned int)(EXP) & (unsigned int)((1 << EXP_BITS) - 1)))
59
60/* Various headers condition prototypes on #ifdef REAL_VALUE_TYPE, so it
61   needs to be a macro.  We do need to continue to have a structure tag
62   so that other headers can forward declare it.  */
63#define REAL_VALUE_TYPE struct real_value
64
65/* We store a REAL_VALUE_TYPE into an rtx, and we do this by putting it in
66   consecutive "w" slots.  Moreover, we've got to compute the number of "w"
67   slots at preprocessor time, which means we can't use sizeof.  Guess.  */
68
69#define REAL_VALUE_TYPE_SIZE (SIGNIFICAND_BITS + 32)
70#define REAL_WIDTH \
71  (REAL_VALUE_TYPE_SIZE/HOST_BITS_PER_WIDE_INT \
72   + (REAL_VALUE_TYPE_SIZE%HOST_BITS_PER_WIDE_INT ? 1 : 0)) /* round up */
73
74/* Verify the guess.  */
75extern char test_real_width
76  [sizeof(REAL_VALUE_TYPE) <= REAL_WIDTH*sizeof(HOST_WIDE_INT) ? 1 : -1];
77
78/* Calculate the format for CONST_DOUBLE.  We need as many slots as
79   are necessary to overlay a REAL_VALUE_TYPE on them.  This could be
80   as many as four (32-bit HOST_WIDE_INT, 128-bit REAL_VALUE_TYPE).
81
82   A number of places assume that there are always at least two 'w'
83   slots in a CONST_DOUBLE, so we provide them even if one would suffice.  */
84
85#if REAL_WIDTH == 1
86# define CONST_DOUBLE_FORMAT	 "ww"
87#else
88# if REAL_WIDTH == 2
89#  define CONST_DOUBLE_FORMAT	 "ww"
90# else
91#  if REAL_WIDTH == 3
92#   define CONST_DOUBLE_FORMAT	 "www"
93#  else
94#   if REAL_WIDTH == 4
95#    define CONST_DOUBLE_FORMAT	 "wwww"
96#   else
97#    if REAL_WIDTH == 5
98#     define CONST_DOUBLE_FORMAT "wwwww"
99#    else
100#     if REAL_WIDTH == 6
101#      define CONST_DOUBLE_FORMAT "wwwwww"
102#     else
103       #error "REAL_WIDTH > 6 not supported"
104#     endif
105#    endif
106#   endif
107#  endif
108# endif
109#endif
110
111
112/* Describes the properties of the specific target format in use.  */
113struct real_format
114{
115  /* Move to and from the target bytes.  */
116  void (*encode) (const struct real_format *, long *,
117		  const REAL_VALUE_TYPE *);
118  void (*decode) (const struct real_format *, REAL_VALUE_TYPE *,
119		  const long *);
120
121  /* The radix of the exponent and digits of the significand.  */
122  int b;
123
124  /* Size of the significand in digits of radix B.  */
125  int p;
126
127  /* Size of the significant of a NaN, in digits of radix B.  */
128  int pnan;
129
130  /* The minimum negative integer, x, such that b**(x-1) is normalized.  */
131  int emin;
132
133  /* The maximum integer, x, such that b**(x-1) is representable.  */
134  int emax;
135
136  /* The bit position of the sign bit, for determining whether a value
137     is positive/negative, or -1 for a complex encoding.  */
138  int signbit_ro;
139
140  /* The bit position of the sign bit, for changing the sign of a number,
141     or -1 for a complex encoding.  */
142  int signbit_rw;
143
144  /* Default rounding mode for operations on this format.  */
145  bool round_towards_zero;
146  bool has_sign_dependent_rounding;
147
148  /* Properties of the format.  */
149  bool has_nans;
150  bool has_inf;
151  bool has_denorm;
152  bool has_signed_zero;
153  bool qnan_msb_set;
154  bool canonical_nan_lsbs_set;
155};
156
157
158/* The target format used for each floating point mode.
159   Float modes are followed by decimal float modes, with entries for
160   float modes indexed by (MODE - first float mode), and entries for
161   decimal float modes indexed by (MODE - first decimal float mode) +
162   the number of float modes.  */
163extern const struct real_format *
164  real_format_for_mode[MAX_MODE_FLOAT - MIN_MODE_FLOAT + 1
165		       + MAX_MODE_DECIMAL_FLOAT - MIN_MODE_DECIMAL_FLOAT + 1];
166
167#define REAL_MODE_FORMAT(MODE)						\
168  (real_format_for_mode[DECIMAL_FLOAT_MODE_P (MODE)			\
169			? (((MODE) - MIN_MODE_DECIMAL_FLOAT)		\
170			   + (MAX_MODE_FLOAT - MIN_MODE_FLOAT + 1))	\
171			: ((MODE) - MIN_MODE_FLOAT)])
172
173#define FLOAT_MODE_FORMAT(MODE) \
174  (REAL_MODE_FORMAT (SCALAR_FLOAT_MODE_P (MODE)? (MODE) \
175					       : GET_MODE_INNER (MODE)))
176
177/* The following macro determines whether the floating point format is
178   composite, i.e. may contain non-consecutive mantissa bits, in which
179   case compile-time FP overflow may not model run-time overflow.  */
180#define MODE_COMPOSITE_P(MODE) \
181  (FLOAT_MODE_P (MODE) \
182   && FLOAT_MODE_FORMAT (MODE)->pnan < FLOAT_MODE_FORMAT (MODE)->p)
183
184/* Accessor macros for format properties.  */
185#define MODE_HAS_NANS(MODE) \
186  (FLOAT_MODE_P (MODE) && FLOAT_MODE_FORMAT (MODE)->has_nans)
187#define MODE_HAS_INFINITIES(MODE) \
188  (FLOAT_MODE_P (MODE) && FLOAT_MODE_FORMAT (MODE)->has_inf)
189#define MODE_HAS_SIGNED_ZEROS(MODE) \
190  (FLOAT_MODE_P (MODE) && FLOAT_MODE_FORMAT (MODE)->has_signed_zero)
191#define MODE_HAS_SIGN_DEPENDENT_ROUNDING(MODE) \
192  (FLOAT_MODE_P (MODE) \
193   && FLOAT_MODE_FORMAT (MODE)->has_sign_dependent_rounding)
194
195/* True if the given mode has a NaN representation and the treatment of
196   NaN operands is important.  Certain optimizations, such as folding
197   x * 0 into 0, are not correct for NaN operands, and are normally
198   disabled for modes with NaNs.  The user can ask for them to be
199   done anyway using the -funsafe-math-optimizations switch.  */
200#define HONOR_NANS(MODE) \
201  (MODE_HAS_NANS (MODE) && !flag_finite_math_only)
202
203/* Like HONOR_NANs, but true if we honor signaling NaNs (or sNaNs).  */
204#define HONOR_SNANS(MODE) (flag_signaling_nans && HONOR_NANS (MODE))
205
206/* As for HONOR_NANS, but true if the mode can represent infinity and
207   the treatment of infinite values is important.  */
208#define HONOR_INFINITIES(MODE) \
209  (MODE_HAS_INFINITIES (MODE) && !flag_finite_math_only)
210
211/* Like HONOR_NANS, but true if the given mode distinguishes between
212   positive and negative zero, and the sign of zero is important.  */
213#define HONOR_SIGNED_ZEROS(MODE) \
214  (MODE_HAS_SIGNED_ZEROS (MODE) && flag_signed_zeros)
215
216/* Like HONOR_NANS, but true if given mode supports sign-dependent rounding,
217   and the rounding mode is important.  */
218#define HONOR_SIGN_DEPENDENT_ROUNDING(MODE) \
219  (MODE_HAS_SIGN_DEPENDENT_ROUNDING (MODE) && flag_rounding_math)
220
221/* Declare functions in real.c.  */
222
223/* Binary or unary arithmetic on tree_code.  */
224extern bool real_arithmetic (REAL_VALUE_TYPE *, int, const REAL_VALUE_TYPE *,
225			     const REAL_VALUE_TYPE *);
226
227/* Compare reals by tree_code.  */
228extern bool real_compare (int, const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
229
230/* Determine whether a floating-point value X is infinite.  */
231extern bool real_isinf (const REAL_VALUE_TYPE *);
232
233/* Determine whether a floating-point value X is a NaN.  */
234extern bool real_isnan (const REAL_VALUE_TYPE *);
235
236/* Determine whether a floating-point value X is finite.  */
237extern bool real_isfinite (const REAL_VALUE_TYPE *);
238
239/* Determine whether a floating-point value X is negative.  */
240extern bool real_isneg (const REAL_VALUE_TYPE *);
241
242/* Determine whether a floating-point value X is minus zero.  */
243extern bool real_isnegzero (const REAL_VALUE_TYPE *);
244
245/* Compare two floating-point objects for bitwise identity.  */
246extern bool real_identical (const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
247
248/* Extend or truncate to a new mode.  */
249extern void real_convert (REAL_VALUE_TYPE *, enum machine_mode,
250			  const REAL_VALUE_TYPE *);
251
252/* Return true if truncating to NEW is exact.  */
253extern bool exact_real_truncate (enum machine_mode, const REAL_VALUE_TYPE *);
254
255/* Render R as a decimal floating point constant.  */
256extern void real_to_decimal (char *, const REAL_VALUE_TYPE *, size_t,
257			     size_t, int);
258
259/* Render R as a decimal floating point constant, rounded so as to be
260   parsed back to the same value when interpreted in mode MODE.  */
261extern void real_to_decimal_for_mode (char *, const REAL_VALUE_TYPE *, size_t,
262				      size_t, int, enum machine_mode);
263
264/* Render R as a hexadecimal floating point constant.  */
265extern void real_to_hexadecimal (char *, const REAL_VALUE_TYPE *,
266				 size_t, size_t, int);
267
268/* Render R as an integer.  */
269extern HOST_WIDE_INT real_to_integer (const REAL_VALUE_TYPE *);
270extern void real_to_integer2 (HOST_WIDE_INT *, HOST_WIDE_INT *,
271			      const REAL_VALUE_TYPE *);
272
273/* Initialize R from a decimal or hexadecimal string.  Return -1 if
274   the value underflows, +1 if overflows, and 0 otherwise.  */
275extern int real_from_string (REAL_VALUE_TYPE *, const char *);
276/* Wrapper to allow different internal representation for decimal floats. */
277extern void real_from_string3 (REAL_VALUE_TYPE *, const char *, enum machine_mode);
278
279/* Initialize R from an integer pair HIGH/LOW.  */
280extern void real_from_integer (REAL_VALUE_TYPE *, enum machine_mode,
281			       unsigned HOST_WIDE_INT, HOST_WIDE_INT, int);
282
283extern long real_to_target_fmt (long *, const REAL_VALUE_TYPE *,
284				const struct real_format *);
285extern long real_to_target (long *, const REAL_VALUE_TYPE *, enum machine_mode);
286
287extern void real_from_target_fmt (REAL_VALUE_TYPE *, const long *,
288				  const struct real_format *);
289extern void real_from_target (REAL_VALUE_TYPE *, const long *,
290			      enum machine_mode);
291
292extern void real_inf (REAL_VALUE_TYPE *);
293
294extern bool real_nan (REAL_VALUE_TYPE *, const char *, int, enum machine_mode);
295
296extern void real_maxval (REAL_VALUE_TYPE *, int, enum machine_mode);
297
298extern void real_2expN (REAL_VALUE_TYPE *, int, enum machine_mode);
299
300extern unsigned int real_hash (const REAL_VALUE_TYPE *);
301
302
303/* Target formats defined in real.c.  */
304extern const struct real_format ieee_single_format;
305extern const struct real_format mips_single_format;
306extern const struct real_format motorola_single_format;
307extern const struct real_format spu_single_format;
308extern const struct real_format ieee_double_format;
309extern const struct real_format mips_double_format;
310extern const struct real_format motorola_double_format;
311extern const struct real_format ieee_extended_motorola_format;
312extern const struct real_format ieee_extended_intel_96_format;
313extern const struct real_format ieee_extended_intel_96_round_53_format;
314extern const struct real_format ieee_extended_intel_128_format;
315extern const struct real_format ibm_extended_format;
316extern const struct real_format mips_extended_format;
317extern const struct real_format ieee_quad_format;
318extern const struct real_format mips_quad_format;
319extern const struct real_format vax_f_format;
320extern const struct real_format vax_d_format;
321extern const struct real_format vax_g_format;
322extern const struct real_format real_internal_format;
323extern const struct real_format decimal_single_format;
324extern const struct real_format decimal_double_format;
325extern const struct real_format decimal_quad_format;
326extern const struct real_format ieee_half_format;
327extern const struct real_format arm_half_format;
328
329
330/* ====================================================================== */
331/* Crap.  */
332
333#define REAL_ARITHMETIC(value, code, d1, d2) \
334  real_arithmetic (&(value), code, &(d1), &(d2))
335
336#define REAL_VALUES_IDENTICAL(x, y)	real_identical (&(x), &(y))
337#define REAL_VALUES_EQUAL(x, y)		real_compare (EQ_EXPR, &(x), &(y))
338#define REAL_VALUES_LESS(x, y)		real_compare (LT_EXPR, &(x), &(y))
339
340/* Determine whether a floating-point value X is infinite.  */
341#define REAL_VALUE_ISINF(x)		real_isinf (&(x))
342
343/* Determine whether a floating-point value X is a NaN.  */
344#define REAL_VALUE_ISNAN(x)		real_isnan (&(x))
345
346/* Determine whether a floating-point value X is negative.  */
347#define REAL_VALUE_NEGATIVE(x)		real_isneg (&(x))
348
349/* Determine whether a floating-point value X is minus zero.  */
350#define REAL_VALUE_MINUS_ZERO(x)	real_isnegzero (&(x))
351
352/* IN is a REAL_VALUE_TYPE.  OUT is an array of longs.  */
353#define REAL_VALUE_TO_TARGET_LONG_DOUBLE(IN, OUT)			\
354  real_to_target (OUT, &(IN),						\
355		  mode_for_size (LONG_DOUBLE_TYPE_SIZE, MODE_FLOAT, 0))
356
357#define REAL_VALUE_TO_TARGET_DOUBLE(IN, OUT) \
358  real_to_target (OUT, &(IN), mode_for_size (64, MODE_FLOAT, 0))
359
360/* IN is a REAL_VALUE_TYPE.  OUT is a long.  */
361#define REAL_VALUE_TO_TARGET_SINGLE(IN, OUT) \
362  ((OUT) = real_to_target (NULL, &(IN), mode_for_size (32, MODE_FLOAT, 0)))
363
364#define REAL_VALUE_FROM_INT(r, lo, hi, mode) \
365  real_from_integer (&(r), mode, lo, hi, 0)
366
367#define REAL_VALUE_FROM_UNSIGNED_INT(r, lo, hi, mode) \
368  real_from_integer (&(r), mode, lo, hi, 1)
369
370/* Real values to IEEE 754 decimal floats.  */
371
372/* IN is a REAL_VALUE_TYPE.  OUT is an array of longs.  */
373#define REAL_VALUE_TO_TARGET_DECIMAL128(IN, OUT) \
374  real_to_target (OUT, &(IN), mode_for_size (128, MODE_DECIMAL_FLOAT, 0))
375
376#define REAL_VALUE_TO_TARGET_DECIMAL64(IN, OUT) \
377  real_to_target (OUT, &(IN), mode_for_size (64, MODE_DECIMAL_FLOAT, 0))
378
379/* IN is a REAL_VALUE_TYPE.  OUT is a long.  */
380#define REAL_VALUE_TO_TARGET_DECIMAL32(IN, OUT) \
381  ((OUT) = real_to_target (NULL, &(IN), mode_for_size (32, MODE_DECIMAL_FLOAT, 0)))
382
383extern REAL_VALUE_TYPE real_value_truncate (enum machine_mode,
384					    REAL_VALUE_TYPE);
385
386#define REAL_VALUE_TO_INT(plow, phigh, r) \
387  real_to_integer2 (plow, phigh, &(r))
388
389extern REAL_VALUE_TYPE real_value_negate (const REAL_VALUE_TYPE *);
390extern REAL_VALUE_TYPE real_value_abs (const REAL_VALUE_TYPE *);
391
392extern int significand_size (enum machine_mode);
393
394extern REAL_VALUE_TYPE real_from_string2 (const char *, enum machine_mode);
395
396#define REAL_VALUE_ATOF(s, m) \
397  real_from_string2 (s, m)
398
399#define CONST_DOUBLE_ATOF(s, m) \
400  CONST_DOUBLE_FROM_REAL_VALUE (real_from_string2 (s, m), m)
401
402#define REAL_VALUE_FIX(r) \
403  real_to_integer (&(r))
404
405/* ??? Not quite right.  */
406#define REAL_VALUE_UNSIGNED_FIX(r) \
407  real_to_integer (&(r))
408
409/* ??? These were added for Paranoia support.  */
410
411/* Return floor log2(R).  */
412extern int real_exponent (const REAL_VALUE_TYPE *);
413
414/* R = A * 2**EXP.  */
415extern void real_ldexp (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *, int);
416
417/* **** End of software floating point emulator interface macros **** */
418
419/* Constant real values 0, 1, 2, -1 and 0.5.  */
420
421extern REAL_VALUE_TYPE dconst0;
422extern REAL_VALUE_TYPE dconst1;
423extern REAL_VALUE_TYPE dconst2;
424extern REAL_VALUE_TYPE dconstm1;
425extern REAL_VALUE_TYPE dconsthalf;
426
427#define dconst_e()  (*dconst_e_ptr ())
428#define dconst_third()  (*dconst_third_ptr ())
429#define dconst_sqrt2()  (*dconst_sqrt2_ptr ())
430
431/* Function to return the real value special constant 'e'.  */
432extern const REAL_VALUE_TYPE * dconst_e_ptr (void);
433
434/* Returns the special REAL_VALUE_TYPE corresponding to 1/3.  */
435extern const REAL_VALUE_TYPE * dconst_third_ptr (void);
436
437/* Returns the special REAL_VALUE_TYPE corresponding to sqrt(2).  */
438extern const REAL_VALUE_TYPE * dconst_sqrt2_ptr (void);
439
440/* Function to return a real value (not a tree node)
441   from a given integer constant.  */
442REAL_VALUE_TYPE real_value_from_int_cst (const_tree, const_tree);
443
444/* Given a CONST_DOUBLE in FROM, store into TO the value it represents.  */
445#define REAL_VALUE_FROM_CONST_DOUBLE(to, from) \
446  ((to) = *CONST_DOUBLE_REAL_VALUE (from))
447
448/* Return a CONST_DOUBLE with value R and mode M.  */
449#define CONST_DOUBLE_FROM_REAL_VALUE(r, m) \
450  const_double_from_real_value (r, m)
451extern rtx const_double_from_real_value (REAL_VALUE_TYPE, enum machine_mode);
452
453/* Replace R by 1/R in the given machine mode, if the result is exact.  */
454extern bool exact_real_inverse (enum machine_mode, REAL_VALUE_TYPE *);
455
456/* Return true if arithmetic on values in IMODE that were promoted
457   from values in TMODE is equivalent to direct arithmetic on values
458   in TMODE.  */
459bool real_can_shorten_arithmetic (enum machine_mode, enum machine_mode);
460
461/* In tree.c: wrap up a REAL_VALUE_TYPE in a tree node.  */
462extern tree build_real (tree, REAL_VALUE_TYPE);
463
464/* Calculate R as the square root of X in the given machine mode.  */
465extern bool real_sqrt (REAL_VALUE_TYPE *, enum machine_mode,
466		       const REAL_VALUE_TYPE *);
467
468/* Calculate R as X raised to the integer exponent N in mode MODE.  */
469extern bool real_powi (REAL_VALUE_TYPE *, enum machine_mode,
470		       const REAL_VALUE_TYPE *, HOST_WIDE_INT);
471
472/* Standard round to integer value functions.  */
473extern void real_trunc (REAL_VALUE_TYPE *, enum machine_mode,
474			const REAL_VALUE_TYPE *);
475extern void real_floor (REAL_VALUE_TYPE *, enum machine_mode,
476			const REAL_VALUE_TYPE *);
477extern void real_ceil (REAL_VALUE_TYPE *, enum machine_mode,
478		       const REAL_VALUE_TYPE *);
479extern void real_round (REAL_VALUE_TYPE *, enum machine_mode,
480			const REAL_VALUE_TYPE *);
481
482/* Set the sign of R to the sign of X.  */
483extern void real_copysign (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
484
485/* Check whether the real constant value given is an integer.  */
486extern bool real_isinteger (const REAL_VALUE_TYPE *c, enum machine_mode mode);
487
488/* Write into BUF the maximum representable finite floating-point
489   number, (1 - b**-p) * b**emax for a given FP format FMT as a hex
490   float string.  BUF must be large enough to contain the result.  */
491extern void get_max_float (const struct real_format *, char *, size_t);
492#endif /* ! GCC_REAL_H */
493