real.h revision 132718 
1/* Definitions of floating-point access for GNU compiler.
2   Copyright (C) 1989, 1991, 1994, 1996, 1997, 1998, 1999,
3   2000, 2002, 2003 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, 59 Temple Place - Suite 330, Boston, MA
20   02111-1307, 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 - 5)
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  ENUM_BITFIELD (real_value_class) class : 2;
46  unsigned int sign : 1;
47  unsigned int signalling : 1;
48  unsigned int canonical : 1;
49  signed int exp : EXP_BITS;
50  unsigned long sig[SIGSZ];
51};
52
53/* Various headers condition prototypes on #ifdef REAL_VALUE_TYPE, so it
54   needs to be a macro.  We do need to continue to have a structure tag
55   so that other headers can forward declare it.  */
56#define REAL_VALUE_TYPE struct real_value
57
58/* We store a REAL_VALUE_TYPE into an rtx, and we do this by putting it in
59   consecutive "w" slots.  Moreover, we've got to compute the number of "w"
60   slots at preprocessor time, which means we can't use sizeof.  Guess.  */
61
62#define REAL_VALUE_TYPE_SIZE (SIGNIFICAND_BITS + 32)
63#define REAL_WIDTH \
64  (REAL_VALUE_TYPE_SIZE/HOST_BITS_PER_WIDE_INT \
65   + (REAL_VALUE_TYPE_SIZE%HOST_BITS_PER_WIDE_INT ? 1 : 0)) /* round up */
66
67/* Verify the guess.  */
68extern char test_real_width
69  [sizeof(REAL_VALUE_TYPE) <= REAL_WIDTH*sizeof(HOST_WIDE_INT) ? 1 : -1];
70
71/* Calculate the format for CONST_DOUBLE.  We need as many slots as
72   are necessary to overlay a REAL_VALUE_TYPE on them.  This could be
73   as many as four (32-bit HOST_WIDE_INT, 128-bit REAL_VALUE_TYPE).
74
75   A number of places assume that there are always at least two 'w'
76   slots in a CONST_DOUBLE, so we provide them even if one would suffice.  */
77
78#if REAL_WIDTH == 1
79# define CONST_DOUBLE_FORMAT	 "ww"
80#else
81# if REAL_WIDTH == 2
82#  define CONST_DOUBLE_FORMAT	 "ww"
83# else
84#  if REAL_WIDTH == 3
85#   define CONST_DOUBLE_FORMAT	 "www"
86#  else
87#   if REAL_WIDTH == 4
88#    define CONST_DOUBLE_FORMAT	 "wwww"
89#   else
90#    if REAL_WIDTH == 5
91#     define CONST_DOUBLE_FORMAT "wwwww"
92#    else
93#     if REAL_WIDTH == 6
94#      define CONST_DOUBLE_FORMAT "wwwwww"
95#     else
96       #error "REAL_WIDTH > 6 not supported"
97#     endif
98#    endif
99#   endif
100#  endif
101# endif
102#endif
103
104
105/* Describes the properties of the specific target format in use.  */
106struct real_format
107{
108  /* Move to and from the target bytes.  */
109  void (*encode) (const struct real_format *, long *,
110		  const REAL_VALUE_TYPE *);
111  void (*decode) (const struct real_format *, REAL_VALUE_TYPE *,
112		  const long *);
113
114  /* The radix of the exponent and digits of the significand.  */
115  int b;
116
117  /* log2(b).  */
118  int log2_b;
119
120  /* Size of the significand in digits of radix B.  */
121  int p;
122
123  /* Size of the significant of a NaN, in digits of radix B.  */
124  int pnan;
125
126  /* The minimum negative integer, x, such that b**(x-1) is normalized.  */
127  int emin;
128
129  /* The maximum integer, x, such that b**(x-1) is representable.  */
130  int emax;
131
132  /* The bit position of the sign bit, or -1 for a complex encoding.  */
133  int signbit;
134
135  /* Properties of the format.  */
136  bool has_nans;
137  bool has_inf;
138  bool has_denorm;
139  bool has_signed_zero;
140  bool qnan_msb_set;
141};
142
143
144/* The target format used for each floating floating point mode.
145   Indexed by MODE - QFmode.  */
146extern const struct real_format *
147  real_format_for_mode[MAX_MODE_FLOAT - MIN_MODE_FLOAT + 1];
148
149#define REAL_MODE_FORMAT(MODE) (real_format_for_mode[(MODE) - MIN_MODE_FLOAT])
150
151/* Declare functions in real.c.  */
152
153/* Binary or unary arithmetic on tree_code.  */
154extern void real_arithmetic (REAL_VALUE_TYPE *, int, const REAL_VALUE_TYPE *,
155			     const REAL_VALUE_TYPE *);
156
157/* Compare reals by tree_code.  */
158extern bool real_compare (int, const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
159
160/* Determine whether a floating-point value X is infinite.  */
161extern bool real_isinf (const REAL_VALUE_TYPE *);
162
163/* Determine whether a floating-point value X is a NaN.  */
164extern bool real_isnan (const REAL_VALUE_TYPE *);
165
166/* Determine whether a floating-point value X is negative.  */
167extern bool real_isneg (const REAL_VALUE_TYPE *);
168
169/* Determine whether a floating-point value X is minus zero.  */
170extern bool real_isnegzero (const REAL_VALUE_TYPE *);
171
172/* Compare two floating-point objects for bitwise identity.  */
173extern bool real_identical (const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
174
175/* Extend or truncate to a new mode.  */
176extern void real_convert (REAL_VALUE_TYPE *, enum machine_mode,
177			  const REAL_VALUE_TYPE *);
178
179/* Return true if truncating to NEW is exact.  */
180extern bool exact_real_truncate (enum machine_mode, const REAL_VALUE_TYPE *);
181
182/* Render R as a decimal floating point constant.  */
183extern void real_to_decimal (char *, const REAL_VALUE_TYPE *, size_t,
184			     size_t, int);
185
186/* Render R as a hexadecimal floating point constant.  */
187extern void real_to_hexadecimal (char *, const REAL_VALUE_TYPE *,
188				 size_t, size_t, int);
189
190/* Render R as an integer.  */
191extern HOST_WIDE_INT real_to_integer (const REAL_VALUE_TYPE *);
192extern void real_to_integer2 (HOST_WIDE_INT *, HOST_WIDE_INT *,
193			      const REAL_VALUE_TYPE *);
194
195/* Initialize R from a decimal or hexadecimal string.  */
196extern void real_from_string (REAL_VALUE_TYPE *, const char *);
197
198/* Initialize R from an integer pair HIGH/LOW.  */
199extern void real_from_integer (REAL_VALUE_TYPE *, enum machine_mode,
200			       unsigned HOST_WIDE_INT, HOST_WIDE_INT, int);
201
202extern long real_to_target_fmt (long *, const REAL_VALUE_TYPE *,
203				const struct real_format *);
204extern long real_to_target (long *, const REAL_VALUE_TYPE *, enum machine_mode);
205
206extern void real_from_target_fmt (REAL_VALUE_TYPE *, const long *,
207				  const struct real_format *);
208extern void real_from_target (REAL_VALUE_TYPE *, const long *,
209			      enum machine_mode);
210
211extern void real_inf (REAL_VALUE_TYPE *);
212
213extern bool real_nan (REAL_VALUE_TYPE *, const char *, int, enum machine_mode);
214
215extern void real_maxval (REAL_VALUE_TYPE *, int, enum machine_mode);
216
217extern void real_2expN (REAL_VALUE_TYPE *, int);
218
219extern unsigned int real_hash (const REAL_VALUE_TYPE *);
220
221
222/* Target formats defined in real.c.  */
223extern const struct real_format ieee_single_format;
224extern const struct real_format mips_single_format;
225extern const struct real_format ieee_double_format;
226extern const struct real_format mips_double_format;
227extern const struct real_format ieee_extended_motorola_format;
228extern const struct real_format ieee_extended_intel_96_format;
229extern const struct real_format ieee_extended_intel_96_round_53_format;
230extern const struct real_format ieee_extended_intel_128_format;
231extern const struct real_format ibm_extended_format;
232extern const struct real_format mips_extended_format;
233extern const struct real_format ieee_quad_format;
234extern const struct real_format mips_quad_format;
235extern const struct real_format vax_f_format;
236extern const struct real_format vax_d_format;
237extern const struct real_format vax_g_format;
238extern const struct real_format i370_single_format;
239extern const struct real_format i370_double_format;
240extern const struct real_format c4x_single_format;
241extern const struct real_format c4x_extended_format;
242extern const struct real_format real_internal_format;
243
244
245/* ====================================================================== */
246/* Crap.  */
247
248#define REAL_ARITHMETIC(value, code, d1, d2) \
249  real_arithmetic (&(value), code, &(d1), &(d2))
250
251#define REAL_VALUES_IDENTICAL(x, y)	real_identical (&(x), &(y))
252#define REAL_VALUES_EQUAL(x, y)		real_compare (EQ_EXPR, &(x), &(y))
253#define REAL_VALUES_LESS(x, y)		real_compare (LT_EXPR, &(x), &(y))
254
255/* Determine whether a floating-point value X is infinite.  */
256#define REAL_VALUE_ISINF(x)		real_isinf (&(x))
257
258/* Determine whether a floating-point value X is a NaN.  */
259#define REAL_VALUE_ISNAN(x)		real_isnan (&(x))
260
261/* Determine whether a floating-point value X is negative.  */
262#define REAL_VALUE_NEGATIVE(x)		real_isneg (&(x))
263
264/* Determine whether a floating-point value X is minus zero.  */
265#define REAL_VALUE_MINUS_ZERO(x)	real_isnegzero (&(x))
266
267/* IN is a REAL_VALUE_TYPE.  OUT is an array of longs.  */
268#define REAL_VALUE_TO_TARGET_LONG_DOUBLE(IN, OUT)			\
269  real_to_target (OUT, &(IN),						\
270		  mode_for_size (LONG_DOUBLE_TYPE_SIZE, MODE_FLOAT, 0))
271
272#define REAL_VALUE_TO_TARGET_DOUBLE(IN, OUT) \
273  real_to_target (OUT, &(IN), mode_for_size (64, MODE_FLOAT, 0))
274
275/* IN is a REAL_VALUE_TYPE.  OUT is a long.  */
276#define REAL_VALUE_TO_TARGET_SINGLE(IN, OUT) \
277  ((OUT) = real_to_target (NULL, &(IN), mode_for_size (32, MODE_FLOAT, 0)))
278
279#define REAL_VALUE_FROM_INT(r, lo, hi, mode) \
280  real_from_integer (&(r), mode, lo, hi, 0)
281
282#define REAL_VALUE_FROM_UNSIGNED_INT(r, lo, hi, mode) \
283  real_from_integer (&(r), mode, lo, hi, 1)
284
285extern REAL_VALUE_TYPE real_value_truncate (enum machine_mode,
286					    REAL_VALUE_TYPE);
287
288#define REAL_VALUE_TO_INT(plow, phigh, r) \
289  real_to_integer2 (plow, phigh, &(r))
290
291extern REAL_VALUE_TYPE real_arithmetic2 (int, const REAL_VALUE_TYPE *,
292					 const REAL_VALUE_TYPE *);
293
294#define REAL_VALUE_NEGATE(X) \
295  real_arithmetic2 (NEGATE_EXPR, &(X), NULL)
296
297#define REAL_VALUE_ABS(X) \
298  real_arithmetic2 (ABS_EXPR, &(X), NULL)
299
300extern int significand_size (enum machine_mode);
301
302extern REAL_VALUE_TYPE real_from_string2 (const char *, enum machine_mode);
303
304#define REAL_VALUE_ATOF(s, m) \
305  real_from_string2 (s, m)
306
307#define CONST_DOUBLE_ATOF(s, m) \
308  CONST_DOUBLE_FROM_REAL_VALUE (real_from_string2 (s, m), m)
309
310#define REAL_VALUE_FIX(r) \
311  real_to_integer (&(r))
312
313/* ??? Not quite right.  */
314#define REAL_VALUE_UNSIGNED_FIX(r) \
315  real_to_integer (&(r))
316
317/* ??? These were added for Paranoia support.  */
318
319/* Return floor log2(R).  */
320extern int real_exponent (const REAL_VALUE_TYPE *);
321
322/* R = A * 2**EXP.  */
323extern void real_ldexp (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *, int);
324
325/* **** End of software floating point emulator interface macros **** */
326
327/* Constant real values 0, 1, 2, 3, 10, -1, -2, 0.5 and 1/3.  */
328
329extern REAL_VALUE_TYPE dconst0;
330extern REAL_VALUE_TYPE dconst1;
331extern REAL_VALUE_TYPE dconst2;
332extern REAL_VALUE_TYPE dconst3;
333extern REAL_VALUE_TYPE dconst10;
334extern REAL_VALUE_TYPE dconstm1;
335extern REAL_VALUE_TYPE dconstm2;
336extern REAL_VALUE_TYPE dconsthalf;
337extern REAL_VALUE_TYPE dconstthird;
338extern REAL_VALUE_TYPE dconstpi;
339extern REAL_VALUE_TYPE dconste;
340
341/* Function to return a real value (not a tree node)
342   from a given integer constant.  */
343REAL_VALUE_TYPE real_value_from_int_cst (tree, tree);
344
345/* Given a CONST_DOUBLE in FROM, store into TO the value it represents.  */
346#define REAL_VALUE_FROM_CONST_DOUBLE(to, from) \
347  memcpy (&(to), &CONST_DOUBLE_LOW ((from)), sizeof (REAL_VALUE_TYPE))
348
349/* Return a CONST_DOUBLE with value R and mode M.  */
350#define CONST_DOUBLE_FROM_REAL_VALUE(r, m) \
351  const_double_from_real_value (r, m)
352extern rtx const_double_from_real_value (REAL_VALUE_TYPE, enum machine_mode);
353
354/* Replace R by 1/R in the given machine mode, if the result is exact.  */
355extern bool exact_real_inverse (enum machine_mode, REAL_VALUE_TYPE *);
356
357/* In tree.c: wrap up a REAL_VALUE_TYPE in a tree node.  */
358extern tree build_real (tree, REAL_VALUE_TYPE);
359
360/* Calculate R as the square root of X in the given machine mode.  */
361extern bool real_sqrt (REAL_VALUE_TYPE *, enum machine_mode,
362		       const REAL_VALUE_TYPE *);
363
364/* Calculate R as X raised to the integer exponent N in mode MODE.  */
365extern bool real_powi (REAL_VALUE_TYPE *, enum machine_mode,
366		       const REAL_VALUE_TYPE *, HOST_WIDE_INT);
367
368/* Standard round to integer value functions.  */
369extern void real_trunc (REAL_VALUE_TYPE *, enum machine_mode,
370			const REAL_VALUE_TYPE *);
371extern void real_floor (REAL_VALUE_TYPE *, enum machine_mode,
372			const REAL_VALUE_TYPE *);
373extern void real_ceil (REAL_VALUE_TYPE *, enum machine_mode,
374		       const REAL_VALUE_TYPE *);
375
376#endif /* ! GCC_REAL_H */
377