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 Free Software Foundation, Inc.
4
5   This file is part of GCC.
6
7   GCC is free software; you can redistribute it and/or modify it under
8   the terms of the GNU General Public License as published by the Free
9   Software Foundation; either version 2, or (at your option) any later
10   version.
11
12   GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13   WARRANTY; without even the implied warranty of MERCHANTABILITY or
14   FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
15   for more details.
16
17   You should have received a copy of the GNU General Public License
18   along with GCC; see the file COPYING.  If not, write to the Free
19   Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
20   02110-1301, USA.  */
21
22#ifndef GCC_REAL_H
23#define GCC_REAL_H
24
25#include "machmode.h"
26
27/* An expanded form of the represented number.  */
28
29/* Enumerate the special cases of numbers that we encounter.  */
30enum real_value_class {
31  rvc_zero,
32  rvc_normal,
33  rvc_inf,
34  rvc_nan
35};
36
37#define SIGNIFICAND_BITS	(128 + HOST_BITS_PER_LONG)
38#define EXP_BITS		(32 - 6)
39#define MAX_EXP			((1 << (EXP_BITS - 1)) - 1)
40#define SIGSZ			(SIGNIFICAND_BITS / HOST_BITS_PER_LONG)
41#define SIG_MSB			((unsigned long)1 << (HOST_BITS_PER_LONG - 1))
42
43struct real_value GTY(())
44{
45  /* Use the same underlying type for all bit-fields, so as to make
46     sure they're packed together, otherwise REAL_VALUE_TYPE_SIZE will
47     be miscomputed.  */
48  unsigned int /* ENUM_BITFIELD (real_value_class) */ cl : 2;
49  unsigned int decimal : 1;
50  unsigned int sign : 1;
51  unsigned int signalling : 1;
52  unsigned int canonical : 1;
53  unsigned int uexp : EXP_BITS;
54  unsigned long sig[SIGSZ];
55};
56
57#define REAL_EXP(REAL) \
58  ((int)((REAL)->uexp ^ (unsigned int)(1 << (EXP_BITS - 1))) \
59   - (1 << (EXP_BITS - 1)))
60#define SET_REAL_EXP(REAL, EXP) \
61  ((REAL)->uexp = ((unsigned int)(EXP) & (unsigned int)((1 << EXP_BITS) - 1)))
62
63/* Various headers condition prototypes on #ifdef REAL_VALUE_TYPE, so it
64   needs to be a macro.  We do need to continue to have a structure tag
65   so that other headers can forward declare it.  */
66#define REAL_VALUE_TYPE struct real_value
67
68/* We store a REAL_VALUE_TYPE into an rtx, and we do this by putting it in
69   consecutive "w" slots.  Moreover, we've got to compute the number of "w"
70   slots at preprocessor time, which means we can't use sizeof.  Guess.  */
71
72#define REAL_VALUE_TYPE_SIZE (SIGNIFICAND_BITS + 32)
73#define REAL_WIDTH \
74  (REAL_VALUE_TYPE_SIZE/HOST_BITS_PER_WIDE_INT \
75   + (REAL_VALUE_TYPE_SIZE%HOST_BITS_PER_WIDE_INT ? 1 : 0)) /* round up */
76
77/* Verify the guess.  */
78extern char test_real_width
79  [sizeof(REAL_VALUE_TYPE) <= REAL_WIDTH*sizeof(HOST_WIDE_INT) ? 1 : -1];
80
81/* Calculate the format for CONST_DOUBLE.  We need as many slots as
82   are necessary to overlay a REAL_VALUE_TYPE on them.  This could be
83   as many as four (32-bit HOST_WIDE_INT, 128-bit REAL_VALUE_TYPE).
84
85   A number of places assume that there are always at least two 'w'
86   slots in a CONST_DOUBLE, so we provide them even if one would suffice.  */
87
88#if REAL_WIDTH == 1
89# define CONST_DOUBLE_FORMAT	 "ww"
90#else
91# if REAL_WIDTH == 2
92#  define CONST_DOUBLE_FORMAT	 "ww"
93# else
94#  if REAL_WIDTH == 3
95#   define CONST_DOUBLE_FORMAT	 "www"
96#  else
97#   if REAL_WIDTH == 4
98#    define CONST_DOUBLE_FORMAT	 "wwww"
99#   else
100#    if REAL_WIDTH == 5
101#     define CONST_DOUBLE_FORMAT "wwwww"
102#    else
103#     if REAL_WIDTH == 6
104#      define CONST_DOUBLE_FORMAT "wwwwww"
105#     else
106       #error "REAL_WIDTH > 6 not supported"
107#     endif
108#    endif
109#   endif
110#  endif
111# endif
112#endif
113
114
115/* Describes the properties of the specific target format in use.  */
116struct real_format
117{
118  /* Move to and from the target bytes.  */
119  void (*encode) (const struct real_format *, long *,
120		  const REAL_VALUE_TYPE *);
121  void (*decode) (const struct real_format *, REAL_VALUE_TYPE *,
122		  const long *);
123
124  /* The radix of the exponent and digits of the significand.  */
125  int b;
126
127  /* log2(b).  */
128  int log2_b;
129
130  /* Size of the significand in digits of radix B.  */
131  int p;
132
133  /* Size of the significant of a NaN, in digits of radix B.  */
134  int pnan;
135
136  /* The minimum negative integer, x, such that b**(x-1) is normalized.  */
137  int emin;
138
139  /* The maximum integer, x, such that b**(x-1) is representable.  */
140  int emax;
141
142  /* The bit position of the sign bit, for determining whether a value
143     is positive/negative, or -1 for a complex encoding.  */
144  int signbit_ro;
145
146  /* The bit position of the sign bit, for changing the sign of a number,
147     or -1 for a complex encoding.  */
148  int signbit_rw;
149
150  /* Properties of the format.  */
151  bool has_nans;
152  bool has_inf;
153  bool has_denorm;
154  bool has_signed_zero;
155  bool qnan_msb_set;
156};
157
158
159/* The target format used for each floating point mode.
160   Float modes are followed by decimal float modes, with entries for
161   float modes indexed by (MODE - first float mode), and entries for
162   decimal float modes indexed by (MODE - first decimal float mode) +
163   the number of float modes.  */
164extern const struct real_format *
165  real_format_for_mode[MAX_MODE_FLOAT - MIN_MODE_FLOAT + 1
166		       + MAX_MODE_DECIMAL_FLOAT - MIN_MODE_DECIMAL_FLOAT + 1];
167
168#define REAL_MODE_FORMAT(MODE)						\
169  (real_format_for_mode[DECIMAL_FLOAT_MODE_P (MODE)			\
170			? ((MODE - MIN_MODE_DECIMAL_FLOAT)		\
171			   + (MAX_MODE_FLOAT - MIN_MODE_FLOAT + 1))	\
172			: (MODE - MIN_MODE_FLOAT)])
173
174/* The following macro determines whether the floating point format is
175   composite, i.e. may contain non-consecutive mantissa bits, in which
176   case compile-time FP overflow may not model run-time overflow.  */
177#define REAL_MODE_FORMAT_COMPOSITE_P(MODE) \
178	((REAL_MODE_FORMAT(MODE))->pnan < (REAL_MODE_FORMAT (MODE))->p)
179
180/* Declare functions in real.c.  */
181
182/* Binary or unary arithmetic on tree_code.  */
183extern bool real_arithmetic (REAL_VALUE_TYPE *, int, const REAL_VALUE_TYPE *,
184			     const REAL_VALUE_TYPE *);
185
186/* Compare reals by tree_code.  */
187extern bool real_compare (int, const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
188
189/* Determine whether a floating-point value X is infinite.  */
190extern bool real_isinf (const REAL_VALUE_TYPE *);
191
192/* Determine whether a floating-point value X is a NaN.  */
193extern bool real_isnan (const REAL_VALUE_TYPE *);
194
195/* Determine whether a floating-point value X is negative.  */
196extern bool real_isneg (const REAL_VALUE_TYPE *);
197
198/* Determine whether a floating-point value X is minus zero.  */
199extern bool real_isnegzero (const REAL_VALUE_TYPE *);
200
201/* Compare two floating-point objects for bitwise identity.  */
202extern bool real_identical (const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
203
204/* Extend or truncate to a new mode.  */
205extern void real_convert (REAL_VALUE_TYPE *, enum machine_mode,
206			  const REAL_VALUE_TYPE *);
207
208/* Return true if truncating to NEW is exact.  */
209extern bool exact_real_truncate (enum machine_mode, const REAL_VALUE_TYPE *);
210
211/* Render R as a decimal floating point constant.  */
212extern void real_to_decimal (char *, const REAL_VALUE_TYPE *, size_t,
213			     size_t, int);
214
215/* Render R as a hexadecimal floating point constant.  */
216extern void real_to_hexadecimal (char *, const REAL_VALUE_TYPE *,
217				 size_t, size_t, int);
218
219/* Render R as an integer.  */
220extern HOST_WIDE_INT real_to_integer (const REAL_VALUE_TYPE *);
221extern void real_to_integer2 (HOST_WIDE_INT *, HOST_WIDE_INT *,
222			      const REAL_VALUE_TYPE *);
223
224/* Initialize R from a decimal or hexadecimal string.  */
225extern void real_from_string (REAL_VALUE_TYPE *, const char *);
226/* Wrapper to allow different internal representation for decimal floats. */
227extern void real_from_string3 (REAL_VALUE_TYPE *, const char *, enum machine_mode);
228
229/* Initialize R from an integer pair HIGH/LOW.  */
230extern void real_from_integer (REAL_VALUE_TYPE *, enum machine_mode,
231			       unsigned HOST_WIDE_INT, HOST_WIDE_INT, int);
232
233extern long real_to_target_fmt (long *, const REAL_VALUE_TYPE *,
234				const struct real_format *);
235extern long real_to_target (long *, const REAL_VALUE_TYPE *, enum machine_mode);
236
237extern void real_from_target_fmt (REAL_VALUE_TYPE *, const long *,
238				  const struct real_format *);
239extern void real_from_target (REAL_VALUE_TYPE *, const long *,
240			      enum machine_mode);
241
242extern void real_inf (REAL_VALUE_TYPE *);
243
244extern bool real_nan (REAL_VALUE_TYPE *, const char *, int, enum machine_mode);
245
246extern void real_maxval (REAL_VALUE_TYPE *, int, enum machine_mode);
247
248extern void real_2expN (REAL_VALUE_TYPE *, int);
249
250extern unsigned int real_hash (const REAL_VALUE_TYPE *);
251
252
253/* Target formats defined in real.c.  */
254extern const struct real_format ieee_single_format;
255extern const struct real_format mips_single_format;
256extern const struct real_format ieee_double_format;
257extern const struct real_format mips_double_format;
258extern const struct real_format ieee_extended_motorola_format;
259extern const struct real_format ieee_extended_intel_96_format;
260extern const struct real_format ieee_extended_intel_96_round_53_format;
261extern const struct real_format ieee_extended_intel_128_format;
262extern const struct real_format ibm_extended_format;
263extern const struct real_format mips_extended_format;
264extern const struct real_format ieee_quad_format;
265extern const struct real_format mips_quad_format;
266extern const struct real_format vax_f_format;
267extern const struct real_format vax_d_format;
268extern const struct real_format vax_g_format;
269extern const struct real_format i370_single_format;
270extern const struct real_format i370_double_format;
271extern const struct real_format c4x_single_format;
272extern const struct real_format c4x_extended_format;
273extern const struct real_format real_internal_format;
274extern const struct real_format decimal_single_format;
275extern const struct real_format decimal_double_format;
276extern const struct real_format decimal_quad_format;
277
278
279/* ====================================================================== */
280/* Crap.  */
281
282#define REAL_ARITHMETIC(value, code, d1, d2) \
283  real_arithmetic (&(value), code, &(d1), &(d2))
284
285#define REAL_VALUES_IDENTICAL(x, y)	real_identical (&(x), &(y))
286#define REAL_VALUES_EQUAL(x, y)		real_compare (EQ_EXPR, &(x), &(y))
287#define REAL_VALUES_LESS(x, y)		real_compare (LT_EXPR, &(x), &(y))
288
289/* Determine whether a floating-point value X is infinite.  */
290#define REAL_VALUE_ISINF(x)		real_isinf (&(x))
291
292/* Determine whether a floating-point value X is a NaN.  */
293#define REAL_VALUE_ISNAN(x)		real_isnan (&(x))
294
295/* Determine whether a floating-point value X is negative.  */
296#define REAL_VALUE_NEGATIVE(x)		real_isneg (&(x))
297
298/* Determine whether a floating-point value X is minus zero.  */
299#define REAL_VALUE_MINUS_ZERO(x)	real_isnegzero (&(x))
300
301/* IN is a REAL_VALUE_TYPE.  OUT is an array of longs.  */
302#define REAL_VALUE_TO_TARGET_LONG_DOUBLE(IN, OUT)			\
303  real_to_target (OUT, &(IN),						\
304		  mode_for_size (LONG_DOUBLE_TYPE_SIZE, MODE_FLOAT, 0))
305
306#define REAL_VALUE_TO_TARGET_DOUBLE(IN, OUT) \
307  real_to_target (OUT, &(IN), mode_for_size (64, MODE_FLOAT, 0))
308
309/* IN is a REAL_VALUE_TYPE.  OUT is a long.  */
310#define REAL_VALUE_TO_TARGET_SINGLE(IN, OUT) \
311  ((OUT) = real_to_target (NULL, &(IN), mode_for_size (32, MODE_FLOAT, 0)))
312
313#define REAL_VALUE_FROM_INT(r, lo, hi, mode) \
314  real_from_integer (&(r), mode, lo, hi, 0)
315
316#define REAL_VALUE_FROM_UNSIGNED_INT(r, lo, hi, mode) \
317  real_from_integer (&(r), mode, lo, hi, 1)
318
319/* Real values to IEEE 754R decimal floats.  */
320
321/* IN is a REAL_VALUE_TYPE.  OUT is an array of longs.  */
322#define REAL_VALUE_TO_TARGET_DECIMAL128(IN, OUT) \
323  real_to_target (OUT, &(IN), mode_for_size (128, MODE_DECIMAL_FLOAT, 0))
324
325#define REAL_VALUE_TO_TARGET_DECIMAL64(IN, OUT) \
326  real_to_target (OUT, &(IN), mode_for_size (64, MODE_DECIMAL_FLOAT, 0))
327
328/* IN is a REAL_VALUE_TYPE.  OUT is a long.  */
329#define REAL_VALUE_TO_TARGET_DECIMAL32(IN, OUT) \
330  ((OUT) = real_to_target (NULL, &(IN), mode_for_size (32, MODE_DECIMAL_FLOAT, 0)))
331
332extern REAL_VALUE_TYPE real_value_truncate (enum machine_mode,
333					    REAL_VALUE_TYPE);
334
335#define REAL_VALUE_TO_INT(plow, phigh, r) \
336  real_to_integer2 (plow, phigh, &(r))
337
338extern REAL_VALUE_TYPE real_arithmetic2 (int, const REAL_VALUE_TYPE *,
339					 const REAL_VALUE_TYPE *);
340
341#define REAL_VALUE_NEGATE(X) \
342  real_arithmetic2 (NEGATE_EXPR, &(X), NULL)
343
344#define REAL_VALUE_ABS(X) \
345  real_arithmetic2 (ABS_EXPR, &(X), NULL)
346
347extern int significand_size (enum machine_mode);
348
349extern REAL_VALUE_TYPE real_from_string2 (const char *, enum machine_mode);
350
351#define REAL_VALUE_ATOF(s, m) \
352  real_from_string2 (s, m)
353
354#define CONST_DOUBLE_ATOF(s, m) \
355  CONST_DOUBLE_FROM_REAL_VALUE (real_from_string2 (s, m), m)
356
357#define REAL_VALUE_FIX(r) \
358  real_to_integer (&(r))
359
360/* ??? Not quite right.  */
361#define REAL_VALUE_UNSIGNED_FIX(r) \
362  real_to_integer (&(r))
363
364/* ??? These were added for Paranoia support.  */
365
366/* Return floor log2(R).  */
367extern int real_exponent (const REAL_VALUE_TYPE *);
368
369/* R = A * 2**EXP.  */
370extern void real_ldexp (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *, int);
371
372/* **** End of software floating point emulator interface macros **** */
373
374/* Constant real values 0, 1, 2, 3, 10, -1, -2, 0.5 and 1/3.  */
375
376extern REAL_VALUE_TYPE dconst0;
377extern REAL_VALUE_TYPE dconst1;
378extern REAL_VALUE_TYPE dconst2;
379extern REAL_VALUE_TYPE dconst3;
380extern REAL_VALUE_TYPE dconst10;
381extern REAL_VALUE_TYPE dconstm1;
382extern REAL_VALUE_TYPE dconstm2;
383extern REAL_VALUE_TYPE dconsthalf;
384extern REAL_VALUE_TYPE dconstthird;
385extern REAL_VALUE_TYPE dconstpi;
386extern REAL_VALUE_TYPE dconste;
387
388/* Function to return a real value (not a tree node)
389   from a given integer constant.  */
390REAL_VALUE_TYPE real_value_from_int_cst (tree, tree);
391
392/* Given a CONST_DOUBLE in FROM, store into TO the value it represents.  */
393#define REAL_VALUE_FROM_CONST_DOUBLE(to, from) \
394  ((to) = *CONST_DOUBLE_REAL_VALUE (from))
395
396/* Return a CONST_DOUBLE with value R and mode M.  */
397#define CONST_DOUBLE_FROM_REAL_VALUE(r, m) \
398  const_double_from_real_value (r, m)
399extern rtx const_double_from_real_value (REAL_VALUE_TYPE, enum machine_mode);
400
401/* Replace R by 1/R in the given machine mode, if the result is exact.  */
402extern bool exact_real_inverse (enum machine_mode, REAL_VALUE_TYPE *);
403
404/* In tree.c: wrap up a REAL_VALUE_TYPE in a tree node.  */
405extern tree build_real (tree, REAL_VALUE_TYPE);
406
407/* Calculate R as the square root of X in the given machine mode.  */
408extern bool real_sqrt (REAL_VALUE_TYPE *, enum machine_mode,
409		       const REAL_VALUE_TYPE *);
410
411/* Calculate R as X raised to the integer exponent N in mode MODE.  */
412extern bool real_powi (REAL_VALUE_TYPE *, enum machine_mode,
413		       const REAL_VALUE_TYPE *, HOST_WIDE_INT);
414
415/* Standard round to integer value functions.  */
416extern void real_trunc (REAL_VALUE_TYPE *, enum machine_mode,
417			const REAL_VALUE_TYPE *);
418extern void real_floor (REAL_VALUE_TYPE *, enum machine_mode,
419			const REAL_VALUE_TYPE *);
420extern void real_ceil (REAL_VALUE_TYPE *, enum machine_mode,
421		       const REAL_VALUE_TYPE *);
422extern void real_round (REAL_VALUE_TYPE *, enum machine_mode,
423			const REAL_VALUE_TYPE *);
424
425/* Set the sign of R to the sign of X.  */
426extern void real_copysign (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
427
428#endif /* ! GCC_REAL_H */
429