1 /* Decimal floating point support.
2    Copyright (C) 2005-2016 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 #include "config.h"
21 #include "system.h"
22 #include "coretypes.h"
23 #include "tm.h"
24 #include "tree.h"
25 #include "dfp.h"
26 
27 /* The order of the following headers is important for making sure
28    decNumber structure is large enough to hold decimal128 digits.  */
29 
30 #include "decimal128.h"
31 #include "decimal64.h"
32 #include "decimal32.h"
33 
34 #ifndef WORDS_BIGENDIAN
35 #define WORDS_BIGENDIAN 0
36 #endif
37 
38 /* Initialize R (a real with the decimal flag set) from DN.  Can
39    utilize status passed in via CONTEXT, if a previous operation had
40    interesting status.  */
41 
42 static void
decimal_from_decnumber(REAL_VALUE_TYPE * r,decNumber * dn,decContext * context)43 decimal_from_decnumber (REAL_VALUE_TYPE *r, decNumber *dn, decContext *context)
44 {
45   memset (r, 0, sizeof (REAL_VALUE_TYPE));
46 
47   r->cl = rvc_normal;
48   if (decNumberIsNaN (dn))
49     r->cl = rvc_nan;
50   if (decNumberIsInfinite (dn))
51     r->cl = rvc_inf;
52   if (context->status & DEC_Overflow)
53     r->cl = rvc_inf;
54   if (decNumberIsNegative (dn))
55     r->sign = 1;
56   r->decimal = 1;
57 
58   if (r->cl != rvc_normal)
59     return;
60 
61   decContextDefault (context, DEC_INIT_DECIMAL128);
62   context->traps = 0;
63 
64   decimal128FromNumber ((decimal128 *) r->sig, dn, context);
65 }
66 
67 /* Create decimal encoded R from string S.  */
68 
69 void
decimal_real_from_string(REAL_VALUE_TYPE * r,const char * s)70 decimal_real_from_string (REAL_VALUE_TYPE *r, const char *s)
71 {
72   decNumber dn;
73   decContext set;
74   decContextDefault (&set, DEC_INIT_DECIMAL128);
75   set.traps = 0;
76 
77   decNumberFromString (&dn, s, &set);
78 
79   /* It would be more efficient to store directly in decNumber format,
80      but that is impractical from current data structure size.
81      Encoding as a decimal128 is much more compact.  */
82   decimal_from_decnumber (r, &dn, &set);
83 }
84 
85 /* Initialize a decNumber from a REAL_VALUE_TYPE.  */
86 
87 static void
decimal_to_decnumber(const REAL_VALUE_TYPE * r,decNumber * dn)88 decimal_to_decnumber (const REAL_VALUE_TYPE *r, decNumber *dn)
89 {
90   decContext set;
91   decContextDefault (&set, DEC_INIT_DECIMAL128);
92   set.traps = 0;
93 
94   switch (r->cl)
95     {
96     case rvc_zero:
97       decNumberZero (dn);
98       break;
99     case rvc_inf:
100       decNumberFromString (dn, "Infinity", &set);
101       break;
102     case rvc_nan:
103       if (r->signalling)
104         decNumberFromString (dn, "snan", &set);
105       else
106         decNumberFromString (dn, "nan", &set);
107       break;
108     case rvc_normal:
109       if (!r->decimal)
110 	{
111 	  /* dconst{1,2,m1,half} are used in various places in
112 	     the middle-end and optimizers, allow them here
113 	     as an exception by converting them to decimal.  */
114 	  if (memcmp (r, &dconst1, sizeof (*r)) == 0)
115 	    {
116 	      decNumberFromString (dn, "1", &set);
117 	      break;
118 	    }
119 	  if (memcmp (r, &dconst2, sizeof (*r)) == 0)
120 	    {
121 	      decNumberFromString (dn, "2", &set);
122 	      break;
123 	    }
124 	  if (memcmp (r, &dconstm1, sizeof (*r)) == 0)
125 	    {
126 	      decNumberFromString (dn, "-1", &set);
127 	      break;
128 	    }
129 	  if (memcmp (r, &dconsthalf, sizeof (*r)) == 0)
130 	    {
131 	      decNumberFromString (dn, "0.5", &set);
132 	      break;
133 	    }
134 	  gcc_unreachable ();
135 	}
136       decimal128ToNumber ((const decimal128 *) r->sig, dn);
137       break;
138     default:
139       gcc_unreachable ();
140     }
141 
142   /* Fix up sign bit.  */
143   if (r->sign != decNumberIsNegative (dn))
144     dn->bits ^= DECNEG;
145 }
146 
147 /* Encode a real into an IEEE 754 decimal32 type.  */
148 
149 void
encode_decimal32(const struct real_format * fmt ATTRIBUTE_UNUSED,long * buf,const REAL_VALUE_TYPE * r)150 encode_decimal32 (const struct real_format *fmt ATTRIBUTE_UNUSED,
151 		  long *buf, const REAL_VALUE_TYPE *r)
152 {
153   decNumber dn;
154   decimal32 d32;
155   decContext set;
156   int32_t image;
157 
158   decContextDefault (&set, DEC_INIT_DECIMAL128);
159   set.traps = 0;
160 
161   decimal_to_decnumber (r, &dn);
162   decimal32FromNumber (&d32, &dn, &set);
163 
164   memcpy (&image, d32.bytes, sizeof (int32_t));
165   buf[0] = image;
166 }
167 
168 /* Decode an IEEE 754 decimal32 type into a real.  */
169 
170 void
decode_decimal32(const struct real_format * fmt ATTRIBUTE_UNUSED,REAL_VALUE_TYPE * r,const long * buf)171 decode_decimal32 (const struct real_format *fmt ATTRIBUTE_UNUSED,
172 		  REAL_VALUE_TYPE *r, const long *buf)
173 {
174   decNumber dn;
175   decimal32 d32;
176   decContext set;
177   int32_t image;
178 
179   decContextDefault (&set, DEC_INIT_DECIMAL128);
180   set.traps = 0;
181 
182   image = buf[0];
183   memcpy (&d32.bytes, &image, sizeof (int32_t));
184 
185   decimal32ToNumber (&d32, &dn);
186   decimal_from_decnumber (r, &dn, &set);
187 }
188 
189 /* Encode a real into an IEEE 754 decimal64 type.  */
190 
191 void
encode_decimal64(const struct real_format * fmt ATTRIBUTE_UNUSED,long * buf,const REAL_VALUE_TYPE * r)192 encode_decimal64 (const struct real_format *fmt ATTRIBUTE_UNUSED,
193 		  long *buf, const REAL_VALUE_TYPE *r)
194 {
195   decNumber dn;
196   decimal64 d64;
197   decContext set;
198   int32_t image;
199 
200   decContextDefault (&set, DEC_INIT_DECIMAL128);
201   set.traps = 0;
202 
203   decimal_to_decnumber (r, &dn);
204   decimal64FromNumber (&d64, &dn, &set);
205 
206   if (WORDS_BIGENDIAN == FLOAT_WORDS_BIG_ENDIAN)
207     {
208       memcpy (&image, &d64.bytes[0], sizeof (int32_t));
209       buf[0] = image;
210       memcpy (&image, &d64.bytes[4], sizeof (int32_t));
211       buf[1] = image;
212     }
213   else
214     {
215       memcpy (&image, &d64.bytes[4], sizeof (int32_t));
216       buf[0] = image;
217       memcpy (&image, &d64.bytes[0], sizeof (int32_t));
218       buf[1] = image;
219     }
220 }
221 
222 /* Decode an IEEE 754 decimal64 type into a real.  */
223 
224 void
decode_decimal64(const struct real_format * fmt ATTRIBUTE_UNUSED,REAL_VALUE_TYPE * r,const long * buf)225 decode_decimal64 (const struct real_format *fmt ATTRIBUTE_UNUSED,
226 		  REAL_VALUE_TYPE *r, const long *buf)
227 {
228   decNumber dn;
229   decimal64 d64;
230   decContext set;
231   int32_t image;
232 
233   decContextDefault (&set, DEC_INIT_DECIMAL128);
234   set.traps = 0;
235 
236   if (WORDS_BIGENDIAN == FLOAT_WORDS_BIG_ENDIAN)
237     {
238       image = buf[0];
239       memcpy (&d64.bytes[0], &image, sizeof (int32_t));
240       image = buf[1];
241       memcpy (&d64.bytes[4], &image, sizeof (int32_t));
242     }
243   else
244     {
245       image = buf[1];
246       memcpy (&d64.bytes[0], &image, sizeof (int32_t));
247       image = buf[0];
248       memcpy (&d64.bytes[4], &image, sizeof (int32_t));
249     }
250 
251   decimal64ToNumber (&d64, &dn);
252   decimal_from_decnumber (r, &dn, &set);
253 }
254 
255 /* Encode a real into an IEEE 754 decimal128 type.  */
256 
257 void
encode_decimal128(const struct real_format * fmt ATTRIBUTE_UNUSED,long * buf,const REAL_VALUE_TYPE * r)258 encode_decimal128 (const struct real_format *fmt ATTRIBUTE_UNUSED,
259 		   long *buf, const REAL_VALUE_TYPE *r)
260 {
261   decNumber dn;
262   decContext set;
263   decimal128 d128;
264   int32_t image;
265 
266   decContextDefault (&set, DEC_INIT_DECIMAL128);
267   set.traps = 0;
268 
269   decimal_to_decnumber (r, &dn);
270   decimal128FromNumber (&d128, &dn, &set);
271 
272   if (WORDS_BIGENDIAN == FLOAT_WORDS_BIG_ENDIAN)
273     {
274       memcpy (&image, &d128.bytes[0], sizeof (int32_t));
275       buf[0] = image;
276       memcpy (&image, &d128.bytes[4], sizeof (int32_t));
277       buf[1] = image;
278       memcpy (&image, &d128.bytes[8], sizeof (int32_t));
279       buf[2] = image;
280       memcpy (&image, &d128.bytes[12], sizeof (int32_t));
281       buf[3] = image;
282     }
283   else
284     {
285       memcpy (&image, &d128.bytes[12], sizeof (int32_t));
286       buf[0] = image;
287       memcpy (&image, &d128.bytes[8], sizeof (int32_t));
288       buf[1] = image;
289       memcpy (&image, &d128.bytes[4], sizeof (int32_t));
290       buf[2] = image;
291       memcpy (&image, &d128.bytes[0], sizeof (int32_t));
292       buf[3] = image;
293     }
294 }
295 
296 /* Decode an IEEE 754 decimal128 type into a real.  */
297 
298 void
decode_decimal128(const struct real_format * fmt ATTRIBUTE_UNUSED,REAL_VALUE_TYPE * r,const long * buf)299 decode_decimal128 (const struct real_format *fmt ATTRIBUTE_UNUSED,
300 		   REAL_VALUE_TYPE *r, const long *buf)
301 {
302   decNumber dn;
303   decimal128 d128;
304   decContext set;
305   int32_t image;
306 
307   decContextDefault (&set, DEC_INIT_DECIMAL128);
308   set.traps = 0;
309 
310   if (WORDS_BIGENDIAN == FLOAT_WORDS_BIG_ENDIAN)
311     {
312       image = buf[0];
313       memcpy (&d128.bytes[0],  &image, sizeof (int32_t));
314       image = buf[1];
315       memcpy (&d128.bytes[4],  &image, sizeof (int32_t));
316       image = buf[2];
317       memcpy (&d128.bytes[8],  &image, sizeof (int32_t));
318       image = buf[3];
319       memcpy (&d128.bytes[12], &image, sizeof (int32_t));
320     }
321   else
322     {
323       image = buf[3];
324       memcpy (&d128.bytes[0],  &image, sizeof (int32_t));
325       image = buf[2];
326       memcpy (&d128.bytes[4],  &image, sizeof (int32_t));
327       image = buf[1];
328       memcpy (&d128.bytes[8],  &image, sizeof (int32_t));
329       image = buf[0];
330       memcpy (&d128.bytes[12], &image, sizeof (int32_t));
331     }
332 
333   decimal128ToNumber (&d128, &dn);
334   decimal_from_decnumber (r, &dn, &set);
335 }
336 
337 /* Helper function to convert from a binary real internal
338    representation.  */
339 
340 static void
decimal_to_binary(REAL_VALUE_TYPE * to,const REAL_VALUE_TYPE * from,const real_format * fmt)341 decimal_to_binary (REAL_VALUE_TYPE *to, const REAL_VALUE_TYPE *from,
342 		   const real_format *fmt)
343 {
344   char string[256];
345   const decimal128 *const d128 = (const decimal128 *) from->sig;
346 
347   decimal128ToString (d128, string);
348   real_from_string3 (to, string, fmt);
349 }
350 
351 
352 /* Helper function to convert from a binary real internal
353    representation.  */
354 
355 static void
decimal_from_binary(REAL_VALUE_TYPE * to,const REAL_VALUE_TYPE * from)356 decimal_from_binary (REAL_VALUE_TYPE *to, const REAL_VALUE_TYPE *from)
357 {
358   char string[256];
359 
360   /* We convert to string, then to decNumber then to decimal128.  */
361   real_to_decimal (string, from, sizeof (string), 0, 1);
362   decimal_real_from_string (to, string);
363 }
364 
365 /* Helper function to real.c:do_compare() to handle decimal internal
366    representation including when one of the operands is still in the
367    binary internal representation.  */
368 
369 int
decimal_do_compare(const REAL_VALUE_TYPE * a,const REAL_VALUE_TYPE * b,int nan_result)370 decimal_do_compare (const REAL_VALUE_TYPE *a, const REAL_VALUE_TYPE *b,
371 		    int nan_result)
372 {
373   decContext set;
374   decNumber dn, dn2, dn3;
375   REAL_VALUE_TYPE a1, b1;
376 
377   /* If either operand is non-decimal, create temporary versions.  */
378   if (!a->decimal)
379     {
380       decimal_from_binary (&a1, a);
381       a = &a1;
382     }
383   if (!b->decimal)
384     {
385       decimal_from_binary (&b1, b);
386       b = &b1;
387     }
388 
389   /* Convert into decNumber form for comparison operation.  */
390   decContextDefault (&set, DEC_INIT_DECIMAL128);
391   set.traps = 0;
392   decimal128ToNumber ((const decimal128 *) a->sig, &dn2);
393   decimal128ToNumber ((const decimal128 *) b->sig, &dn3);
394 
395   /* Finally, do the comparison.  */
396   decNumberCompare (&dn, &dn2, &dn3, &set);
397 
398   /* Return the comparison result.  */
399   if (decNumberIsNaN (&dn))
400     return nan_result;
401   else if (decNumberIsZero (&dn))
402     return 0;
403   else if (decNumberIsNegative (&dn))
404     return -1;
405   else
406     return 1;
407 }
408 
409 /* Helper to round_for_format, handling decimal float types.  */
410 
411 void
decimal_round_for_format(const struct real_format * fmt,REAL_VALUE_TYPE * r)412 decimal_round_for_format (const struct real_format *fmt, REAL_VALUE_TYPE *r)
413 {
414   decNumber dn;
415   decContext set;
416 
417   /* Real encoding occurs later.  */
418   if (r->cl != rvc_normal)
419     return;
420 
421   decContextDefault (&set, DEC_INIT_DECIMAL128);
422   set.traps = 0;
423   decimal128ToNumber ((decimal128 *) r->sig, &dn);
424 
425   if (fmt == &decimal_quad_format)
426     {
427       /* The internal format is already in this format.  */
428       return;
429     }
430   else if (fmt == &decimal_single_format)
431     {
432       decimal32 d32;
433       decContextDefault (&set, DEC_INIT_DECIMAL32);
434       set.traps = 0;
435 
436       decimal32FromNumber (&d32, &dn, &set);
437       decimal32ToNumber (&d32, &dn);
438     }
439   else if (fmt == &decimal_double_format)
440     {
441       decimal64 d64;
442       decContextDefault (&set, DEC_INIT_DECIMAL64);
443       set.traps = 0;
444 
445       decimal64FromNumber (&d64, &dn, &set);
446       decimal64ToNumber (&d64, &dn);
447     }
448   else
449     gcc_unreachable ();
450 
451   decimal_from_decnumber (r, &dn, &set);
452 }
453 
454 /* Extend or truncate to a new mode.  Handles conversions between
455    binary and decimal types.  */
456 
457 void
decimal_real_convert(REAL_VALUE_TYPE * r,const real_format * fmt,const REAL_VALUE_TYPE * a)458 decimal_real_convert (REAL_VALUE_TYPE *r, const real_format *fmt,
459 		      const REAL_VALUE_TYPE *a)
460 {
461   if (a->decimal && fmt->b == 10)
462     return;
463   if (a->decimal)
464       decimal_to_binary (r, a, fmt);
465   else
466       decimal_from_binary (r, a);
467 }
468 
469 /* Render R_ORIG as a decimal floating point constant.  Emit DIGITS
470    significant digits in the result, bounded by BUF_SIZE.  If DIGITS
471    is 0, choose the maximum for the representation.  If
472    CROP_TRAILING_ZEROS, strip trailing zeros.  Currently, not honoring
473    DIGITS or CROP_TRAILING_ZEROS.  */
474 
475 void
decimal_real_to_decimal(char * str,const REAL_VALUE_TYPE * r_orig,size_t buf_size,size_t digits ATTRIBUTE_UNUSED,int crop_trailing_zeros ATTRIBUTE_UNUSED)476 decimal_real_to_decimal (char *str, const REAL_VALUE_TYPE *r_orig,
477 			 size_t buf_size,
478 			 size_t digits ATTRIBUTE_UNUSED,
479 			 int crop_trailing_zeros ATTRIBUTE_UNUSED)
480 {
481   const decimal128 *const d128 = (const decimal128*) r_orig->sig;
482 
483   /* decimal128ToString requires space for at least 24 characters;
484      Require two more for suffix.  */
485   gcc_assert (buf_size >= 24);
486   decimal128ToString (d128, str);
487 }
488 
489 static bool
decimal_do_add(REAL_VALUE_TYPE * r,const REAL_VALUE_TYPE * op0,const REAL_VALUE_TYPE * op1,int subtract_p)490 decimal_do_add (REAL_VALUE_TYPE *r, const REAL_VALUE_TYPE *op0,
491 		const REAL_VALUE_TYPE *op1, int subtract_p)
492 {
493   decNumber dn;
494   decContext set;
495   decNumber dn2, dn3;
496 
497   decimal_to_decnumber (op0, &dn2);
498   decimal_to_decnumber (op1, &dn3);
499 
500   decContextDefault (&set, DEC_INIT_DECIMAL128);
501   set.traps = 0;
502 
503   if (subtract_p)
504     decNumberSubtract (&dn, &dn2, &dn3, &set);
505   else
506     decNumberAdd (&dn, &dn2, &dn3, &set);
507 
508   decimal_from_decnumber (r, &dn, &set);
509 
510   /* Return true, if inexact.  */
511   return (set.status & DEC_Inexact);
512 }
513 
514 /* Compute R = OP0 * OP1.  */
515 
516 static bool
decimal_do_multiply(REAL_VALUE_TYPE * r,const REAL_VALUE_TYPE * op0,const REAL_VALUE_TYPE * op1)517 decimal_do_multiply (REAL_VALUE_TYPE *r, const REAL_VALUE_TYPE *op0,
518 		     const REAL_VALUE_TYPE *op1)
519 {
520   decContext set;
521   decNumber dn, dn2, dn3;
522 
523   decimal_to_decnumber (op0, &dn2);
524   decimal_to_decnumber (op1, &dn3);
525 
526   decContextDefault (&set, DEC_INIT_DECIMAL128);
527   set.traps = 0;
528 
529   decNumberMultiply (&dn, &dn2, &dn3, &set);
530   decimal_from_decnumber (r, &dn, &set);
531 
532   /* Return true, if inexact.  */
533   return (set.status & DEC_Inexact);
534 }
535 
536 /* Compute R = OP0 / OP1.  */
537 
538 static bool
decimal_do_divide(REAL_VALUE_TYPE * r,const REAL_VALUE_TYPE * op0,const REAL_VALUE_TYPE * op1)539 decimal_do_divide (REAL_VALUE_TYPE *r, const REAL_VALUE_TYPE *op0,
540 		   const REAL_VALUE_TYPE *op1)
541 {
542   decContext set;
543   decNumber dn, dn2, dn3;
544 
545   decimal_to_decnumber (op0, &dn2);
546   decimal_to_decnumber (op1, &dn3);
547 
548   decContextDefault (&set, DEC_INIT_DECIMAL128);
549   set.traps = 0;
550 
551   decNumberDivide (&dn, &dn2, &dn3, &set);
552   decimal_from_decnumber (r, &dn, &set);
553 
554   /* Return true, if inexact.  */
555   return (set.status & DEC_Inexact);
556 }
557 
558 /* Set R to A truncated to an integral value toward zero (decimal
559    floating point).  */
560 
561 void
decimal_do_fix_trunc(REAL_VALUE_TYPE * r,const REAL_VALUE_TYPE * a)562 decimal_do_fix_trunc (REAL_VALUE_TYPE *r, const REAL_VALUE_TYPE *a)
563 {
564   decNumber dn, dn2;
565   decContext set;
566 
567   decContextDefault (&set, DEC_INIT_DECIMAL128);
568   set.traps = 0;
569   set.round = DEC_ROUND_DOWN;
570   decimal128ToNumber ((const decimal128 *) a->sig, &dn2);
571 
572   decNumberToIntegralValue (&dn, &dn2, &set);
573   decimal_from_decnumber (r, &dn, &set);
574 }
575 
576 /* Render decimal float value R as an integer.  */
577 
578 HOST_WIDE_INT
decimal_real_to_integer(const REAL_VALUE_TYPE * r)579 decimal_real_to_integer (const REAL_VALUE_TYPE *r)
580 {
581   decContext set;
582   decNumber dn, dn2, dn3;
583   REAL_VALUE_TYPE to;
584   char string[256];
585 
586   decContextDefault (&set, DEC_INIT_DECIMAL128);
587   set.traps = 0;
588   set.round = DEC_ROUND_DOWN;
589   decimal128ToNumber ((const decimal128 *) r->sig, &dn);
590 
591   decNumberToIntegralValue (&dn2, &dn, &set);
592   decNumberZero (&dn3);
593   decNumberRescale (&dn, &dn2, &dn3, &set);
594 
595   /* Convert to REAL_VALUE_TYPE and call appropriate conversion
596      function.  */
597   decNumberToString (&dn, string);
598   real_from_string (&to, string);
599   return real_to_integer (&to);
600 }
601 
602 /* Likewise, but returns a wide_int with PRECISION.  *FAIL is set if the
603    value does not fit.  */
604 
605 wide_int
decimal_real_to_integer(const REAL_VALUE_TYPE * r,bool * fail,int precision)606 decimal_real_to_integer (const REAL_VALUE_TYPE *r, bool *fail, int precision)
607 {
608   decContext set;
609   decNumber dn, dn2, dn3;
610   REAL_VALUE_TYPE to;
611   char string[256];
612 
613   decContextDefault (&set, DEC_INIT_DECIMAL128);
614   set.traps = 0;
615   set.round = DEC_ROUND_DOWN;
616   decimal128ToNumber ((const decimal128 *) r->sig, &dn);
617 
618   decNumberToIntegralValue (&dn2, &dn, &set);
619   decNumberZero (&dn3);
620   decNumberRescale (&dn, &dn2, &dn3, &set);
621 
622   /* Convert to REAL_VALUE_TYPE and call appropriate conversion
623      function.  */
624   decNumberToString (&dn, string);
625   real_from_string (&to, string);
626   return real_to_integer (&to, fail, precision);
627 }
628 
629 /* Perform the decimal floating point operation described by CODE.
630    For a unary operation, OP1 will be NULL.  This function returns
631    true if the result may be inexact due to loss of precision.  */
632 
633 bool
decimal_real_arithmetic(REAL_VALUE_TYPE * r,enum tree_code code,const REAL_VALUE_TYPE * op0,const REAL_VALUE_TYPE * op1)634 decimal_real_arithmetic (REAL_VALUE_TYPE *r, enum tree_code code,
635 			 const REAL_VALUE_TYPE *op0,
636 			 const REAL_VALUE_TYPE *op1)
637 {
638   REAL_VALUE_TYPE a, b;
639 
640   /* If either operand is non-decimal, create temporaries.  */
641   if (!op0->decimal)
642     {
643       decimal_from_binary (&a, op0);
644       op0 = &a;
645     }
646   if (op1 && !op1->decimal)
647     {
648       decimal_from_binary (&b, op1);
649       op1 = &b;
650     }
651 
652   switch (code)
653     {
654     case PLUS_EXPR:
655       return decimal_do_add (r, op0, op1, 0);
656 
657     case MINUS_EXPR:
658       return decimal_do_add (r, op0, op1, 1);
659 
660     case MULT_EXPR:
661       return decimal_do_multiply (r, op0, op1);
662 
663     case RDIV_EXPR:
664       return decimal_do_divide (r, op0, op1);
665 
666     case MIN_EXPR:
667       if (op1->cl == rvc_nan)
668         *r = *op1;
669       else if (real_compare (UNLT_EXPR, op0, op1))
670         *r = *op0;
671       else
672         *r = *op1;
673       return false;
674 
675     case MAX_EXPR:
676       if (op1->cl == rvc_nan)
677         *r = *op1;
678       else if (real_compare (LT_EXPR, op0, op1))
679         *r = *op1;
680       else
681         *r = *op0;
682       return false;
683 
684     case NEGATE_EXPR:
685       {
686 	*r = *op0;
687 	/* Flip sign bit.  */
688 	decimal128FlipSign ((decimal128 *) r->sig);
689 	/* Keep sign field in sync.  */
690 	r->sign ^= 1;
691       }
692       return false;
693 
694     case ABS_EXPR:
695       {
696         *r = *op0;
697 	/* Clear sign bit.  */
698 	decimal128ClearSign ((decimal128 *) r->sig);
699 	/* Keep sign field in sync.  */
700 	r->sign = 0;
701       }
702       return false;
703 
704     case FIX_TRUNC_EXPR:
705       decimal_do_fix_trunc (r, op0);
706       return false;
707 
708     default:
709       gcc_unreachable ();
710     }
711 }
712 
713 /* Fills R with the largest finite value representable in mode MODE.
714    If SIGN is nonzero, R is set to the most negative finite value.  */
715 
716 void
decimal_real_maxval(REAL_VALUE_TYPE * r,int sign,machine_mode mode)717 decimal_real_maxval (REAL_VALUE_TYPE *r, int sign, machine_mode mode)
718 {
719   const char *max;
720 
721   switch (mode)
722     {
723     case SDmode:
724       max = "9.999999E96";
725       break;
726     case DDmode:
727       max = "9.999999999999999E384";
728       break;
729     case TDmode:
730       max = "9.999999999999999999999999999999999E6144";
731       break;
732     default:
733       gcc_unreachable ();
734     }
735 
736   decimal_real_from_string (r, max);
737   if (sign)
738     decimal128SetSign ((decimal128 *) r->sig, 1);
739 }
740