1 /* Decimal floating point support.
2 Copyright (C) 2005, 2006, 2007, 2008, 2009 Free Software
5 This file is part of GCC.
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 3, or (at your option) any later
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
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
23 #include "coretypes.h"
31 /* The order of the following headers is important for making sure
32 decNumber structure is large enough to hold decimal128 digits. */
34 #include "decimal128.h"
35 #include "decimal128Local.h"
36 #include "decimal64.h"
37 #include "decimal32.h"
38 #include "decNumber.h"
40 #ifndef WORDS_BIGENDIAN
41 #define WORDS_BIGENDIAN 0
44 /* Initialize R (a real with the decimal flag set) from DN. Can
45 utilize status passed in via CONTEXT, if a previous operation had
46 interesting status. */
49 decimal_from_decnumber (REAL_VALUE_TYPE *r, decNumber *dn, decContext *context)
51 memset (r, 0, sizeof (REAL_VALUE_TYPE));
54 if (decNumberIsNaN (dn))
56 if (decNumberIsInfinite (dn))
58 if (context->status & DEC_Overflow)
60 if (decNumberIsNegative (dn))
64 if (r->cl != rvc_normal)
67 decContextDefault (context, DEC_INIT_DECIMAL128);
70 decimal128FromNumber ((decimal128 *) r->sig, dn, context);
73 /* Create decimal encoded R from string S. */
76 decimal_real_from_string (REAL_VALUE_TYPE *r, const char *s)
80 decContextDefault (&set, DEC_INIT_DECIMAL128);
83 decNumberFromString (&dn, s, &set);
85 /* It would be more efficient to store directly in decNumber format,
86 but that is impractical from current data structure size.
87 Encoding as a decimal128 is much more compact. */
88 decimal_from_decnumber (r, &dn, &set);
91 /* Initialize a decNumber from a REAL_VALUE_TYPE. */
94 decimal_to_decnumber (const REAL_VALUE_TYPE *r, decNumber *dn)
97 decContextDefault (&set, DEC_INIT_DECIMAL128);
106 decNumberFromString (dn, "Infinity", &set);
110 decNumberFromString (dn, "snan", &set);
112 decNumberFromString (dn, "nan", &set);
115 gcc_assert (r->decimal);
116 decimal128ToNumber ((const decimal128 *) r->sig, dn);
122 /* Fix up sign bit. */
123 if (r->sign != decNumberIsNegative (dn))
127 /* Encode a real into an IEEE 754 decimal32 type. */
130 encode_decimal32 (const struct real_format *fmt ATTRIBUTE_UNUSED,
131 long *buf, const REAL_VALUE_TYPE *r)
137 decContextDefault (&set, DEC_INIT_DECIMAL128);
140 decimal_to_decnumber (r, &dn);
141 decimal32FromNumber (&d32, &dn, &set);
143 memcpy (&buf[0], d32.bytes, sizeof (uint32_t));
146 /* Decode an IEEE 754 decimal32 type into a real. */
149 decode_decimal32 (const struct real_format *fmt ATTRIBUTE_UNUSED,
150 REAL_VALUE_TYPE *r, const long *buf)
156 decContextDefault (&set, DEC_INIT_DECIMAL128);
159 memcpy (&d32.bytes, &buf[0], sizeof (uint32_t));
161 decimal32ToNumber (&d32, &dn);
162 decimal_from_decnumber (r, &dn, &set);
165 /* Encode a real into an IEEE 754 decimal64 type. */
168 encode_decimal64 (const struct real_format *fmt ATTRIBUTE_UNUSED,
169 long *buf, const REAL_VALUE_TYPE *r)
175 decContextDefault (&set, DEC_INIT_DECIMAL128);
178 decimal_to_decnumber (r, &dn);
179 decimal64FromNumber (&d64, &dn, &set);
181 if (WORDS_BIGENDIAN == FLOAT_WORDS_BIG_ENDIAN)
183 memcpy (&buf[0], &d64.bytes[0], sizeof (uint32_t));
184 memcpy (&buf[1], &d64.bytes[4], sizeof (uint32_t));
188 memcpy (&buf[0], &d64.bytes[4], sizeof (uint32_t));
189 memcpy (&buf[1], &d64.bytes[0], sizeof (uint32_t));
193 /* Decode an IEEE 754 decimal64 type into a real. */
196 decode_decimal64 (const struct real_format *fmt ATTRIBUTE_UNUSED,
197 REAL_VALUE_TYPE *r, const long *buf)
203 decContextDefault (&set, DEC_INIT_DECIMAL128);
206 if (WORDS_BIGENDIAN == FLOAT_WORDS_BIG_ENDIAN)
208 memcpy (&d64.bytes[0], &buf[0], sizeof (uint32_t));
209 memcpy (&d64.bytes[4], &buf[1], sizeof (uint32_t));
213 memcpy (&d64.bytes[0], &buf[1], sizeof (uint32_t));
214 memcpy (&d64.bytes[4], &buf[0], sizeof (uint32_t));
217 decimal64ToNumber (&d64, &dn);
218 decimal_from_decnumber (r, &dn, &set);
221 /* Encode a real into an IEEE 754 decimal128 type. */
224 encode_decimal128 (const struct real_format *fmt ATTRIBUTE_UNUSED,
225 long *buf, const REAL_VALUE_TYPE *r)
231 decContextDefault (&set, DEC_INIT_DECIMAL128);
234 decimal_to_decnumber (r, &dn);
235 decimal128FromNumber (&d128, &dn, &set);
237 if (WORDS_BIGENDIAN == FLOAT_WORDS_BIG_ENDIAN)
239 memcpy (&buf[0], &d128.bytes[0], sizeof (uint32_t));
240 memcpy (&buf[1], &d128.bytes[4], sizeof (uint32_t));
241 memcpy (&buf[2], &d128.bytes[8], sizeof (uint32_t));
242 memcpy (&buf[3], &d128.bytes[12], sizeof (uint32_t));
246 memcpy (&buf[0], &d128.bytes[12], sizeof (uint32_t));
247 memcpy (&buf[1], &d128.bytes[8], sizeof (uint32_t));
248 memcpy (&buf[2], &d128.bytes[4], sizeof (uint32_t));
249 memcpy (&buf[3], &d128.bytes[0], sizeof (uint32_t));
253 /* Decode an IEEE 754 decimal128 type into a real. */
256 decode_decimal128 (const struct real_format *fmt ATTRIBUTE_UNUSED,
257 REAL_VALUE_TYPE *r, const long *buf)
263 decContextDefault (&set, DEC_INIT_DECIMAL128);
266 if (WORDS_BIGENDIAN == FLOAT_WORDS_BIG_ENDIAN)
268 memcpy (&d128.bytes[0], &buf[0], sizeof (uint32_t));
269 memcpy (&d128.bytes[4], &buf[1], sizeof (uint32_t));
270 memcpy (&d128.bytes[8], &buf[2], sizeof (uint32_t));
271 memcpy (&d128.bytes[12], &buf[3], sizeof (uint32_t));
275 memcpy (&d128.bytes[0], &buf[3], sizeof (uint32_t));
276 memcpy (&d128.bytes[4], &buf[2], sizeof (uint32_t));
277 memcpy (&d128.bytes[8], &buf[1], sizeof (uint32_t));
278 memcpy (&d128.bytes[12], &buf[0], sizeof (uint32_t));
281 decimal128ToNumber (&d128, &dn);
282 decimal_from_decnumber (r, &dn, &set);
285 /* Helper function to convert from a binary real internal
289 decimal_to_binary (REAL_VALUE_TYPE *to, const REAL_VALUE_TYPE *from,
290 enum machine_mode mode)
293 const decimal128 *const d128 = (const decimal128 *) from->sig;
295 decimal128ToString (d128, string);
296 real_from_string3 (to, string, mode);
300 /* Helper function to convert from a binary real internal
304 decimal_from_binary (REAL_VALUE_TYPE *to, const REAL_VALUE_TYPE *from)
308 /* We convert to string, then to decNumber then to decimal128. */
309 real_to_decimal (string, from, sizeof (string), 0, 1);
310 decimal_real_from_string (to, string);
313 /* Helper function to real.c:do_compare() to handle decimal internal
314 representation including when one of the operands is still in the
315 binary internal representation. */
318 decimal_do_compare (const REAL_VALUE_TYPE *a, const REAL_VALUE_TYPE *b,
322 decNumber dn, dn2, dn3;
323 REAL_VALUE_TYPE a1, b1;
325 /* If either operand is non-decimal, create temporary versions. */
328 decimal_from_binary (&a1, a);
333 decimal_from_binary (&b1, b);
337 /* Convert into decNumber form for comparison operation. */
338 decContextDefault (&set, DEC_INIT_DECIMAL128);
340 decimal128ToNumber ((const decimal128 *) a->sig, &dn2);
341 decimal128ToNumber ((const decimal128 *) b->sig, &dn3);
343 /* Finally, do the comparison. */
344 decNumberCompare (&dn, &dn2, &dn3, &set);
346 /* Return the comparison result. */
347 if (decNumberIsNaN (&dn))
349 else if (decNumberIsZero (&dn))
351 else if (decNumberIsNegative (&dn))
357 /* Helper to round_for_format, handling decimal float types. */
360 decimal_round_for_format (const struct real_format *fmt, REAL_VALUE_TYPE *r)
365 /* Real encoding occurs later. */
366 if (r->cl != rvc_normal)
369 decContextDefault (&set, DEC_INIT_DECIMAL128);
371 decimal128ToNumber ((decimal128 *) r->sig, &dn);
373 if (fmt == &decimal_quad_format)
375 /* The internal format is already in this format. */
378 else if (fmt == &decimal_single_format)
381 decContextDefault (&set, DEC_INIT_DECIMAL32);
384 decimal32FromNumber (&d32, &dn, &set);
385 decimal32ToNumber (&d32, &dn);
387 else if (fmt == &decimal_double_format)
390 decContextDefault (&set, DEC_INIT_DECIMAL64);
393 decimal64FromNumber (&d64, &dn, &set);
394 decimal64ToNumber (&d64, &dn);
399 decimal_from_decnumber (r, &dn, &set);
402 /* Extend or truncate to a new mode. Handles conversions between
403 binary and decimal types. */
406 decimal_real_convert (REAL_VALUE_TYPE *r, enum machine_mode mode,
407 const REAL_VALUE_TYPE *a)
409 const struct real_format *fmt = REAL_MODE_FORMAT (mode);
411 if (a->decimal && fmt->b == 10)
414 decimal_to_binary (r, a, mode);
416 decimal_from_binary (r, a);
419 /* Render R_ORIG as a decimal floating point constant. Emit DIGITS
420 significant digits in the result, bounded by BUF_SIZE. If DIGITS
421 is 0, choose the maximum for the representation. If
422 CROP_TRAILING_ZEROS, strip trailing zeros. Currently, not honoring
423 DIGITS or CROP_TRAILING_ZEROS. */
426 decimal_real_to_decimal (char *str, const REAL_VALUE_TYPE *r_orig,
428 size_t digits ATTRIBUTE_UNUSED,
429 int crop_trailing_zeros ATTRIBUTE_UNUSED)
431 const decimal128 *const d128 = (const decimal128*) r_orig->sig;
433 /* decimal128ToString requires space for at least 24 characters;
434 Require two more for suffix. */
435 gcc_assert (buf_size >= 24);
436 decimal128ToString (d128, str);
440 decimal_do_add (REAL_VALUE_TYPE *r, const REAL_VALUE_TYPE *op0,
441 const REAL_VALUE_TYPE *op1, int subtract_p)
447 decimal_to_decnumber (op0, &dn2);
448 decimal_to_decnumber (op1, &dn3);
450 decContextDefault (&set, DEC_INIT_DECIMAL128);
454 decNumberSubtract (&dn, &dn2, &dn3, &set);
456 decNumberAdd (&dn, &dn2, &dn3, &set);
458 decimal_from_decnumber (r, &dn, &set);
460 /* Return true, if inexact. */
461 return (set.status & DEC_Inexact);
464 /* Compute R = OP0 * OP1. */
467 decimal_do_multiply (REAL_VALUE_TYPE *r, const REAL_VALUE_TYPE *op0,
468 const REAL_VALUE_TYPE *op1)
471 decNumber dn, dn2, dn3;
473 decimal_to_decnumber (op0, &dn2);
474 decimal_to_decnumber (op1, &dn3);
476 decContextDefault (&set, DEC_INIT_DECIMAL128);
479 decNumberMultiply (&dn, &dn2, &dn3, &set);
480 decimal_from_decnumber (r, &dn, &set);
482 /* Return true, if inexact. */
483 return (set.status & DEC_Inexact);
486 /* Compute R = OP0 / OP1. */
489 decimal_do_divide (REAL_VALUE_TYPE *r, const REAL_VALUE_TYPE *op0,
490 const REAL_VALUE_TYPE *op1)
493 decNumber dn, dn2, dn3;
495 decimal_to_decnumber (op0, &dn2);
496 decimal_to_decnumber (op1, &dn3);
498 decContextDefault (&set, DEC_INIT_DECIMAL128);
501 decNumberDivide (&dn, &dn2, &dn3, &set);
502 decimal_from_decnumber (r, &dn, &set);
504 /* Return true, if inexact. */
505 return (set.status & DEC_Inexact);
508 /* Set R to A truncated to an integral value toward zero (decimal
512 decimal_do_fix_trunc (REAL_VALUE_TYPE *r, const REAL_VALUE_TYPE *a)
517 decContextDefault (&set, DEC_INIT_DECIMAL128);
519 set.round = DEC_ROUND_DOWN;
520 decimal128ToNumber ((const decimal128 *) a->sig, &dn2);
522 decNumberToIntegralValue (&dn, &dn2, &set);
523 decimal_from_decnumber (r, &dn, &set);
526 /* Render decimal float value R as an integer. */
529 decimal_real_to_integer (const REAL_VALUE_TYPE *r)
532 decNumber dn, dn2, dn3;
536 decContextDefault (&set, DEC_INIT_DECIMAL128);
538 set.round = DEC_ROUND_DOWN;
539 decimal128ToNumber ((const decimal128 *) r->sig, &dn);
541 decNumberToIntegralValue (&dn2, &dn, &set);
542 decNumberZero (&dn3);
543 decNumberRescale (&dn, &dn2, &dn3, &set);
545 /* Convert to REAL_VALUE_TYPE and call appropriate conversion
547 decNumberToString (&dn, string);
548 real_from_string (&to, string);
549 return real_to_integer (&to);
552 /* Likewise, but to an integer pair, HI+LOW. */
555 decimal_real_to_integer2 (HOST_WIDE_INT *plow, HOST_WIDE_INT *phigh,
556 const REAL_VALUE_TYPE *r)
559 decNumber dn, dn2, dn3;
563 decContextDefault (&set, DEC_INIT_DECIMAL128);
565 set.round = DEC_ROUND_DOWN;
566 decimal128ToNumber ((const decimal128 *) r->sig, &dn);
568 decNumberToIntegralValue (&dn2, &dn, &set);
569 decNumberZero (&dn3);
570 decNumberRescale (&dn, &dn2, &dn3, &set);
572 /* Convert to REAL_VALUE_TYPE and call appropriate conversion
574 decNumberToString (&dn, string);
575 real_from_string (&to, string);
576 real_to_integer2 (plow, phigh, &to);
579 /* Perform the decimal floating point operation described by CODE.
580 For a unary operation, OP1 will be NULL. This function returns
581 true if the result may be inexact due to loss of precision. */
584 decimal_real_arithmetic (REAL_VALUE_TYPE *r, enum tree_code code,
585 const REAL_VALUE_TYPE *op0,
586 const REAL_VALUE_TYPE *op1)
588 REAL_VALUE_TYPE a, b;
590 /* If either operand is non-decimal, create temporaries. */
593 decimal_from_binary (&a, op0);
596 if (op1 && !op1->decimal)
598 decimal_from_binary (&b, op1);
605 return decimal_do_add (r, op0, op1, 0);
608 return decimal_do_add (r, op0, op1, 1);
611 return decimal_do_multiply (r, op0, op1);
614 return decimal_do_divide (r, op0, op1);
617 if (op1->cl == rvc_nan)
619 else if (real_compare (UNLT_EXPR, op0, op1))
626 if (op1->cl == rvc_nan)
628 else if (real_compare (LT_EXPR, op0, op1))
638 decimal128FlipSign ((decimal128 *) r->sig);
639 /* Keep sign field in sync. */
647 /* Clear sign bit. */
648 decimal128ClearSign ((decimal128 *) r->sig);
649 /* Keep sign field in sync. */
655 decimal_do_fix_trunc (r, op0);
663 /* Fills R with the largest finite value representable in mode MODE.
664 If SIGN is nonzero, R is set to the most negative finite value. */
667 decimal_real_maxval (REAL_VALUE_TYPE *r, int sign, enum machine_mode mode)
677 max = "9.999999999999999E384";
680 max = "9.999999999999999999999999999999999E6144";
686 decimal_real_from_string (r, max);
688 decimal128SetSign ((decimal128 *) r->sig, 1);