1/* Definitions of floating-point access for GNU compiler.
2   Copyright (C) 1989, 1991, 1994, 1996, 1997, 1998, 1999,
3   2000, 2002, 2003, 2004, 2005, 2007, 2008, 2009, 2010
4   Free Software Foundation, Inc.
5
6   This file is part of GCC.
7
8   GCC is free software; you can redistribute it and/or modify it under
9   the terms of the GNU General Public License as published by the Free
10   Software Foundation; either version 3, or (at your option) any later
11   version.
12
13   GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14   WARRANTY; without even the implied warranty of MERCHANTABILITY or
15   FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
16   for more details.
17
18   You should have received a copy of the GNU General Public License
19   along with GCC; see the file COPYING3.  If not see
20   <http://www.gnu.org/licenses/>.  */
21
22#ifndef GCC_REAL_H
23#define GCC_REAL_H
24
25#ifndef GENERATOR_FILE
26#include <gmp.h>
27#include <mpfr.h>
28#include <mpc.h>
29extern tree do_mpc_arg2 (tree, tree, tree, int, int (*)(mpc_ptr, mpc_srcptr, mpc_srcptr, mpc_rnd_t));
30#endif
31#include "machmode.h"
32
33/* An expanded form of the represented number.  */
34
35/* Enumerate the special cases of numbers that we encounter.  */
36enum real_value_class {
37  rvc_zero,
38  rvc_normal,
39  rvc_inf,
40  rvc_nan
41};
42
43#define SIGNIFICAND_BITS	(128 + HOST_BITS_PER_LONG)
44#define EXP_BITS		(32 - 6)
45#define MAX_EXP			((1 << (EXP_BITS - 1)) - 1)
46#define SIGSZ			(SIGNIFICAND_BITS / HOST_BITS_PER_LONG)
47#define SIG_MSB			((unsigned long)1 << (HOST_BITS_PER_LONG - 1))
48
49struct GTY(()) real_value {
50  /* Use the same underlying type for all bit-fields, so as to make
51     sure they're packed together, otherwise REAL_VALUE_TYPE_SIZE will
52     be miscomputed.  */
53  unsigned int /* ENUM_BITFIELD (real_value_class) */ cl : 2;
54  unsigned int decimal : 1;
55  unsigned int sign : 1;
56  unsigned int signalling : 1;
57  unsigned int canonical : 1;
58  unsigned int uexp : EXP_BITS;
59  unsigned long sig[SIGSZ];
60};
61
62#define REAL_EXP(REAL) \
63  ((int)((REAL)->uexp ^ (unsigned int)(1 << (EXP_BITS - 1))) \
64   - (1 << (EXP_BITS - 1)))
65#define SET_REAL_EXP(REAL, EXP) \
66  ((REAL)->uexp = ((unsigned int)(EXP) & (unsigned int)((1 << EXP_BITS) - 1)))
67
68/* Various headers condition prototypes on #ifdef REAL_VALUE_TYPE, so it
69   needs to be a macro.  We do need to continue to have a structure tag
70   so that other headers can forward declare it.  */
71#define REAL_VALUE_TYPE struct real_value
72
73/* We store a REAL_VALUE_TYPE into an rtx, and we do this by putting it in
74   consecutive "w" slots.  Moreover, we've got to compute the number of "w"
75   slots at preprocessor time, which means we can't use sizeof.  Guess.  */
76
77#define REAL_VALUE_TYPE_SIZE (SIGNIFICAND_BITS + 32)
78#define REAL_WIDTH \
79  (REAL_VALUE_TYPE_SIZE/HOST_BITS_PER_WIDE_INT \
80   + (REAL_VALUE_TYPE_SIZE%HOST_BITS_PER_WIDE_INT ? 1 : 0)) /* round up */
81
82/* Verify the guess.  */
83extern char test_real_width
84  [sizeof(REAL_VALUE_TYPE) <= REAL_WIDTH*sizeof(HOST_WIDE_INT) ? 1 : -1];
85
86/* Calculate the format for CONST_DOUBLE.  We need as many slots as
87   are necessary to overlay a REAL_VALUE_TYPE on them.  This could be
88   as many as four (32-bit HOST_WIDE_INT, 128-bit REAL_VALUE_TYPE).
89
90   A number of places assume that there are always at least two 'w'
91   slots in a CONST_DOUBLE, so we provide them even if one would suffice.  */
92
93#if REAL_WIDTH == 1
94# define CONST_DOUBLE_FORMAT	 "ww"
95#else
96# if REAL_WIDTH == 2
97#  define CONST_DOUBLE_FORMAT	 "ww"
98# else
99#  if REAL_WIDTH == 3
100#   define CONST_DOUBLE_FORMAT	 "www"
101#  else
102#   if REAL_WIDTH == 4
103#    define CONST_DOUBLE_FORMAT	 "wwww"
104#   else
105#    if REAL_WIDTH == 5
106#     define CONST_DOUBLE_FORMAT "wwwww"
107#    else
108#     if REAL_WIDTH == 6
109#      define CONST_DOUBLE_FORMAT "wwwwww"
110#     else
111       #error "REAL_WIDTH > 6 not supported"
112#     endif
113#    endif
114#   endif
115#  endif
116# endif
117#endif
118
119
120/* Describes the properties of the specific target format in use.  */
121struct real_format
122{
123  /* Move to and from the target bytes.  */
124  void (*encode) (const struct real_format *, long *,
125		  const REAL_VALUE_TYPE *);
126  void (*decode) (const struct real_format *, REAL_VALUE_TYPE *,
127		  const long *);
128
129  /* The radix of the exponent and digits of the significand.  */
130  int b;
131
132  /* Size of the significand in digits of radix B.  */
133  int p;
134
135  /* Size of the significant of a NaN, in digits of radix B.  */
136  int pnan;
137
138  /* The minimum negative integer, x, such that b**(x-1) is normalized.  */
139  int emin;
140
141  /* The maximum integer, x, such that b**(x-1) is representable.  */
142  int emax;
143
144  /* The bit position of the sign bit, for determining whether a value
145     is positive/negative, or -1 for a complex encoding.  */
146  int signbit_ro;
147
148  /* The bit position of the sign bit, for changing the sign of a number,
149     or -1 for a complex encoding.  */
150  int signbit_rw;
151
152  /* Default rounding mode for operations on this format.  */
153  bool round_towards_zero;
154  bool has_sign_dependent_rounding;
155
156  /* Properties of the format.  */
157  bool has_nans;
158  bool has_inf;
159  bool has_denorm;
160  bool has_signed_zero;
161  bool qnan_msb_set;
162  bool canonical_nan_lsbs_set;
163};
164
165
166/* The target format used for each floating point mode.
167   Float modes are followed by decimal float modes, with entries for
168   float modes indexed by (MODE - first float mode), and entries for
169   decimal float modes indexed by (MODE - first decimal float mode) +
170   the number of float modes.  */
171extern const struct real_format *
172  real_format_for_mode[MAX_MODE_FLOAT - MIN_MODE_FLOAT + 1
173		       + MAX_MODE_DECIMAL_FLOAT - MIN_MODE_DECIMAL_FLOAT + 1];
174
175#define REAL_MODE_FORMAT(MODE)						\
176  (real_format_for_mode[DECIMAL_FLOAT_MODE_P (MODE)			\
177			? (((MODE) - MIN_MODE_DECIMAL_FLOAT)		\
178			   + (MAX_MODE_FLOAT - MIN_MODE_FLOAT + 1))	\
179			: ((MODE) - MIN_MODE_FLOAT)])
180
181#define FLOAT_MODE_FORMAT(MODE) \
182  (REAL_MODE_FORMAT (SCALAR_FLOAT_MODE_P (MODE)? (MODE) \
183					       : GET_MODE_INNER (MODE)))
184
185/* The following macro determines whether the floating point format is
186   composite, i.e. may contain non-consecutive mantissa bits, in which
187   case compile-time FP overflow may not model run-time overflow.  */
188#define MODE_COMPOSITE_P(MODE) \
189  (FLOAT_MODE_P (MODE) \
190   && FLOAT_MODE_FORMAT (MODE)->pnan < FLOAT_MODE_FORMAT (MODE)->p)
191
192/* Accessor macros for format properties.  */
193#define MODE_HAS_NANS(MODE) \
194  (FLOAT_MODE_P (MODE) && FLOAT_MODE_FORMAT (MODE)->has_nans)
195#define MODE_HAS_INFINITIES(MODE) \
196  (FLOAT_MODE_P (MODE) && FLOAT_MODE_FORMAT (MODE)->has_inf)
197#define MODE_HAS_SIGNED_ZEROS(MODE) \
198  (FLOAT_MODE_P (MODE) && FLOAT_MODE_FORMAT (MODE)->has_signed_zero)
199#define MODE_HAS_SIGN_DEPENDENT_ROUNDING(MODE) \
200  (FLOAT_MODE_P (MODE) \
201   && FLOAT_MODE_FORMAT (MODE)->has_sign_dependent_rounding)
202
203/* True if the given mode has a NaN representation and the treatment of
204   NaN operands is important.  Certain optimizations, such as folding
205   x * 0 into 0, are not correct for NaN operands, and are normally
206   disabled for modes with NaNs.  The user can ask for them to be
207   done anyway using the -funsafe-math-optimizations switch.  */
208#define HONOR_NANS(MODE) \
209  (MODE_HAS_NANS (MODE) && !flag_finite_math_only)
210
211/* Like HONOR_NANs, but true if we honor signaling NaNs (or sNaNs).  */
212#define HONOR_SNANS(MODE) (flag_signaling_nans && HONOR_NANS (MODE))
213
214/* As for HONOR_NANS, but true if the mode can represent infinity and
215   the treatment of infinite values is important.  */
216#define HONOR_INFINITIES(MODE) \
217  (MODE_HAS_INFINITIES (MODE) && !flag_finite_math_only)
218
219/* Like HONOR_NANS, but true if the given mode distinguishes between
220   positive and negative zero, and the sign of zero is important.  */
221#define HONOR_SIGNED_ZEROS(MODE) \
222  (MODE_HAS_SIGNED_ZEROS (MODE) && flag_signed_zeros)
223
224/* Like HONOR_NANS, but true if given mode supports sign-dependent rounding,
225   and the rounding mode is important.  */
226#define HONOR_SIGN_DEPENDENT_ROUNDING(MODE) \
227  (MODE_HAS_SIGN_DEPENDENT_ROUNDING (MODE) && flag_rounding_math)
228
229/* Declare functions in real.c.  */
230
231/* Binary or unary arithmetic on tree_code.  */
232extern bool real_arithmetic (REAL_VALUE_TYPE *, int, const REAL_VALUE_TYPE *,
233			     const REAL_VALUE_TYPE *);
234
235/* Compare reals by tree_code.  */
236extern bool real_compare (int, const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
237
238/* Determine whether a floating-point value X is infinite.  */
239extern bool real_isinf (const REAL_VALUE_TYPE *);
240
241/* Determine whether a floating-point value X is a NaN.  */
242extern bool real_isnan (const REAL_VALUE_TYPE *);
243
244/* Determine whether a floating-point value X is finite.  */
245extern bool real_isfinite (const REAL_VALUE_TYPE *);
246
247/* Determine whether a floating-point value X is negative.  */
248extern bool real_isneg (const REAL_VALUE_TYPE *);
249
250/* Determine whether a floating-point value X is minus zero.  */
251extern bool real_isnegzero (const REAL_VALUE_TYPE *);
252
253/* Compare two floating-point objects for bitwise identity.  */
254extern bool real_identical (const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
255
256/* Extend or truncate to a new mode.  */
257extern void real_convert (REAL_VALUE_TYPE *, enum machine_mode,
258			  const REAL_VALUE_TYPE *);
259
260/* Return true if truncating to NEW is exact.  */
261extern bool exact_real_truncate (enum machine_mode, const REAL_VALUE_TYPE *);
262
263/* Render R as a decimal floating point constant.  */
264extern void real_to_decimal (char *, const REAL_VALUE_TYPE *, size_t,
265			     size_t, int);
266
267/* Render R as a decimal floating point constant, rounded so as to be
268   parsed back to the same value when interpreted in mode MODE.  */
269extern void real_to_decimal_for_mode (char *, const REAL_VALUE_TYPE *, size_t,
270				      size_t, int, enum machine_mode);
271
272/* Render R as a hexadecimal floating point constant.  */
273extern void real_to_hexadecimal (char *, const REAL_VALUE_TYPE *,
274				 size_t, size_t, int);
275
276/* Render R as an integer.  */
277extern HOST_WIDE_INT real_to_integer (const REAL_VALUE_TYPE *);
278extern void real_to_integer2 (HOST_WIDE_INT *, HOST_WIDE_INT *,
279			      const REAL_VALUE_TYPE *);
280
281/* Initialize R from a decimal or hexadecimal string.  Return -1 if
282   the value underflows, +1 if overflows, and 0 otherwise.  */
283extern int real_from_string (REAL_VALUE_TYPE *, const char *);
284/* Wrapper to allow different internal representation for decimal floats. */
285extern void real_from_string3 (REAL_VALUE_TYPE *, const char *, enum machine_mode);
286
287/* Initialize R from an integer pair HIGH/LOW.  */
288extern void real_from_integer (REAL_VALUE_TYPE *, enum machine_mode,
289			       unsigned HOST_WIDE_INT, HOST_WIDE_INT, int);
290
291extern long real_to_target_fmt (long *, const REAL_VALUE_TYPE *,
292				const struct real_format *);
293extern long real_to_target (long *, const REAL_VALUE_TYPE *, enum machine_mode);
294
295extern void real_from_target_fmt (REAL_VALUE_TYPE *, const long *,
296				  const struct real_format *);
297extern void real_from_target (REAL_VALUE_TYPE *, const long *,
298			      enum machine_mode);
299
300extern void real_inf (REAL_VALUE_TYPE *);
301
302extern bool real_nan (REAL_VALUE_TYPE *, const char *, int, enum machine_mode);
303
304extern void real_maxval (REAL_VALUE_TYPE *, int, enum machine_mode);
305
306extern void real_2expN (REAL_VALUE_TYPE *, int, enum machine_mode);
307
308extern unsigned int real_hash (const REAL_VALUE_TYPE *);
309
310
311/* Target formats defined in real.c.  */
312extern const struct real_format ieee_single_format;
313extern const struct real_format mips_single_format;
314extern const struct real_format motorola_single_format;
315extern const struct real_format spu_single_format;
316extern const struct real_format ieee_double_format;
317extern const struct real_format mips_double_format;
318extern const struct real_format motorola_double_format;
319extern const struct real_format ieee_extended_motorola_format;
320extern const struct real_format ieee_extended_intel_96_format;
321extern const struct real_format ieee_extended_intel_96_round_53_format;
322extern const struct real_format ieee_extended_intel_128_format;
323extern const struct real_format ibm_extended_format;
324extern const struct real_format mips_extended_format;
325extern const struct real_format ieee_quad_format;
326extern const struct real_format mips_quad_format;
327extern const struct real_format vax_f_format;
328extern const struct real_format vax_d_format;
329extern const struct real_format vax_g_format;
330extern const struct real_format real_internal_format;
331extern const struct real_format decimal_single_format;
332extern const struct real_format decimal_double_format;
333extern const struct real_format decimal_quad_format;
334extern const struct real_format ieee_half_format;
335extern const struct real_format arm_half_format;
336
337
338/* ====================================================================== */
339/* Crap.  */
340
341#define REAL_ARITHMETIC(value, code, d1, d2) \
342  real_arithmetic (&(value), code, &(d1), &(d2))
343
344#define REAL_VALUES_IDENTICAL(x, y)	real_identical (&(x), &(y))
345#define REAL_VALUES_EQUAL(x, y)		real_compare (EQ_EXPR, &(x), &(y))
346#define REAL_VALUES_LESS(x, y)		real_compare (LT_EXPR, &(x), &(y))
347
348/* Determine whether a floating-point value X is infinite.  */
349#define REAL_VALUE_ISINF(x)		real_isinf (&(x))
350
351/* Determine whether a floating-point value X is a NaN.  */
352#define REAL_VALUE_ISNAN(x)		real_isnan (&(x))
353
354/* Determine whether a floating-point value X is negative.  */
355#define REAL_VALUE_NEGATIVE(x)		real_isneg (&(x))
356
357/* Determine whether a floating-point value X is minus zero.  */
358#define REAL_VALUE_MINUS_ZERO(x)	real_isnegzero (&(x))
359
360/* IN is a REAL_VALUE_TYPE.  OUT is an array of longs.  */
361#define REAL_VALUE_TO_TARGET_LONG_DOUBLE(IN, OUT)			\
362  real_to_target (OUT, &(IN),						\
363		  mode_for_size (LONG_DOUBLE_TYPE_SIZE, MODE_FLOAT, 0))
364
365#define REAL_VALUE_TO_TARGET_DOUBLE(IN, OUT) \
366  real_to_target (OUT, &(IN), mode_for_size (64, MODE_FLOAT, 0))
367
368/* IN is a REAL_VALUE_TYPE.  OUT is a long.  */
369#define REAL_VALUE_TO_TARGET_SINGLE(IN, OUT) \
370  ((OUT) = real_to_target (NULL, &(IN), mode_for_size (32, MODE_FLOAT, 0)))
371
372#define REAL_VALUE_FROM_INT(r, lo, hi, mode) \
373  real_from_integer (&(r), mode, lo, hi, 0)
374
375#define REAL_VALUE_FROM_UNSIGNED_INT(r, lo, hi, mode) \
376  real_from_integer (&(r), mode, lo, hi, 1)
377
378/* Real values to IEEE 754 decimal floats.  */
379
380/* IN is a REAL_VALUE_TYPE.  OUT is an array of longs.  */
381#define REAL_VALUE_TO_TARGET_DECIMAL128(IN, OUT) \
382  real_to_target (OUT, &(IN), mode_for_size (128, MODE_DECIMAL_FLOAT, 0))
383
384#define REAL_VALUE_TO_TARGET_DECIMAL64(IN, OUT) \
385  real_to_target (OUT, &(IN), mode_for_size (64, MODE_DECIMAL_FLOAT, 0))
386
387/* IN is a REAL_VALUE_TYPE.  OUT is a long.  */
388#define REAL_VALUE_TO_TARGET_DECIMAL32(IN, OUT) \
389  ((OUT) = real_to_target (NULL, &(IN), mode_for_size (32, MODE_DECIMAL_FLOAT, 0)))
390
391extern REAL_VALUE_TYPE real_value_truncate (enum machine_mode,
392					    REAL_VALUE_TYPE);
393
394#define REAL_VALUE_TO_INT(plow, phigh, r) \
395  real_to_integer2 (plow, phigh, &(r))
396
397extern REAL_VALUE_TYPE real_arithmetic2 (int, const REAL_VALUE_TYPE *,
398					 const REAL_VALUE_TYPE *);
399
400#define REAL_VALUE_NEGATE(X) \
401  real_arithmetic2 (NEGATE_EXPR, &(X), NULL)
402
403#define REAL_VALUE_ABS(X) \
404  real_arithmetic2 (ABS_EXPR, &(X), NULL)
405
406extern int significand_size (enum machine_mode);
407
408extern REAL_VALUE_TYPE real_from_string2 (const char *, enum machine_mode);
409
410#define REAL_VALUE_ATOF(s, m) \
411  real_from_string2 (s, m)
412
413#define CONST_DOUBLE_ATOF(s, m) \
414  CONST_DOUBLE_FROM_REAL_VALUE (real_from_string2 (s, m), m)
415
416#define REAL_VALUE_FIX(r) \
417  real_to_integer (&(r))
418
419/* ??? Not quite right.  */
420#define REAL_VALUE_UNSIGNED_FIX(r) \
421  real_to_integer (&(r))
422
423/* ??? These were added for Paranoia support.  */
424
425/* Return floor log2(R).  */
426extern int real_exponent (const REAL_VALUE_TYPE *);
427
428/* R = A * 2**EXP.  */
429extern void real_ldexp (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *, int);
430
431/* **** End of software floating point emulator interface macros **** */
432
433/* Constant real values 0, 1, 2, -1 and 0.5.  */
434
435extern REAL_VALUE_TYPE dconst0;
436extern REAL_VALUE_TYPE dconst1;
437extern REAL_VALUE_TYPE dconst2;
438extern REAL_VALUE_TYPE dconstm1;
439extern REAL_VALUE_TYPE dconsthalf;
440
441#define dconst_e()  (*dconst_e_ptr ())
442#define dconst_third()  (*dconst_third_ptr ())
443#define dconst_sqrt2()  (*dconst_sqrt2_ptr ())
444
445/* Function to return the real value special constant 'e'.  */
446extern const REAL_VALUE_TYPE * dconst_e_ptr (void);
447
448/* Returns the special REAL_VALUE_TYPE corresponding to 1/3.  */
449extern const REAL_VALUE_TYPE * dconst_third_ptr (void);
450
451/* Returns the special REAL_VALUE_TYPE corresponding to sqrt(2).  */
452extern const REAL_VALUE_TYPE * dconst_sqrt2_ptr (void);
453
454/* Function to return a real value (not a tree node)
455   from a given integer constant.  */
456REAL_VALUE_TYPE real_value_from_int_cst (const_tree, const_tree);
457
458/* Given a CONST_DOUBLE in FROM, store into TO the value it represents.  */
459#define REAL_VALUE_FROM_CONST_DOUBLE(to, from) \
460  ((to) = *CONST_DOUBLE_REAL_VALUE (from))
461
462/* Return a CONST_DOUBLE with value R and mode M.  */
463#define CONST_DOUBLE_FROM_REAL_VALUE(r, m) \
464  const_double_from_real_value (r, m)
465extern rtx const_double_from_real_value (REAL_VALUE_TYPE, enum machine_mode);
466
467/* Replace R by 1/R in the given machine mode, if the result is exact.  */
468extern bool exact_real_inverse (enum machine_mode, REAL_VALUE_TYPE *);
469
470/* Return true if arithmetic on values in IMODE that were promoted
471   from values in TMODE is equivalent to direct arithmetic on values
472   in TMODE.  */
473bool real_can_shorten_arithmetic (enum machine_mode, enum machine_mode);
474
475/* In tree.c: wrap up a REAL_VALUE_TYPE in a tree node.  */
476extern tree build_real (tree, REAL_VALUE_TYPE);
477
478/* Calculate R as the square root of X in the given machine mode.  */
479extern bool real_sqrt (REAL_VALUE_TYPE *, enum machine_mode,
480		       const REAL_VALUE_TYPE *);
481
482/* Calculate R as X raised to the integer exponent N in mode MODE.  */
483extern bool real_powi (REAL_VALUE_TYPE *, enum machine_mode,
484		       const REAL_VALUE_TYPE *, HOST_WIDE_INT);
485
486/* Standard round to integer value functions.  */
487extern void real_trunc (REAL_VALUE_TYPE *, enum machine_mode,
488			const REAL_VALUE_TYPE *);
489extern void real_floor (REAL_VALUE_TYPE *, enum machine_mode,
490			const REAL_VALUE_TYPE *);
491extern void real_ceil (REAL_VALUE_TYPE *, enum machine_mode,
492		       const REAL_VALUE_TYPE *);
493extern void real_round (REAL_VALUE_TYPE *, enum machine_mode,
494			const REAL_VALUE_TYPE *);
495
496/* Set the sign of R to the sign of X.  */
497extern void real_copysign (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
498
499#ifndef GENERATOR_FILE
500/* Convert between MPFR and REAL_VALUE_TYPE.  The caller is
501   responsible for initializing and clearing the MPFR parameter.  */
502
503extern void real_from_mpfr (REAL_VALUE_TYPE *, mpfr_srcptr, tree, mp_rnd_t);
504extern void mpfr_from_real (mpfr_ptr, const REAL_VALUE_TYPE *, mp_rnd_t);
505#endif
506
507/* Check whether the real constant value given is an integer.  */
508extern bool real_isinteger (const REAL_VALUE_TYPE *c, enum machine_mode mode);
509
510/* Write into BUF the maximum representable finite floating-point
511   number, (1 - b**-p) * b**emax for a given FP format FMT as a hex
512   float string.  BUF must be large enough to contain the result.  */
513extern void get_max_float (const struct real_format *, char *, size_t);
514#endif /* ! GCC_REAL_H */
515