trionan.c@ 13571

Last change on this file since 13571 was 6076, checked in by vboxsync, 17 years ago
Merged dmik/s2 branch (r25959:26751) to the trunk.
Property svn:eol-style set to `native` Property svn:keywords set to `Date Revision Author Id`
File size: 22.5 KB

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1	/*************************************************************************
2	*
3	* $Id: trionan.c 6076 2007-12-14 19:23:03Z vboxsync $
4	*
5	* Copyright (C) 2001 Bjorn Reese <[email protected]>
6	*
7	* Permission to use, copy, modify, and distribute this software for any
8	* purpose with or without fee is hereby granted, provided that the above
9	* copyright notice and this permission notice appear in all copies.
10	*
11	* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
12	* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
13	* MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE AUTHORS AND
14	* CONTRIBUTORS ACCEPT NO RESPONSIBILITY IN ANY CONCEIVABLE MANNER.
15	*
16	************************************************************************
17	*
18	* Functions to handle special quantities in floating-point numbers
19	* (that is, NaNs and infinity). They provide the capability to detect
20	* and fabricate special quantities.
21	*
22	* Although written to be as portable as possible, it can never be
23	* guaranteed to work on all platforms, as not all hardware supports
24	* special quantities.
25	*
26	* The approach used here (approximately) is to:
27	*
28	* 1. Use C99 functionality when available.
29	* 2. Use IEEE 754 bit-patterns if possible.
30	* 3. Use platform-specific techniques.
31	*
32	************************************************************************/
33
34	/*
35	* TODO:
36	* o Put all the magic into trio_fpclassify_and_signbit(), and use this from
37	* trio_isnan() etc.
38	*/
39
40	/*************************************************************************
41	* Include files
42	*/
43	#include "triodef.h"
44	#include "trionan.h"
45
46	#include <math.h>
47	#include <string.h>
48	#include <limits.h>
49	#include <float.h>
50	#if defined(TRIO_PLATFORM_UNIX)
51	# include <signal.h>
52	#endif
53	#if defined(TRIO_COMPILER_DECC)
54	# if defined(__linux__)
55	# include <cpml.h>
56	# else
57	# include <fp_class.h>
58	# endif
59	#endif
60	#include <assert.h>
61
62	#if defined(TRIO_DOCUMENTATION)
63	# include "doc/doc_nan.h"
64	#endif
65	/** @addtogroup SpecialQuantities
66	@{
67	*/
68
69	/*************************************************************************
70	* Definitions
71	*/
72
73	#define TRIO_TRUE (1 == 1)
74	#define TRIO_FALSE (0 == 1)
75
76	/*
77	* We must enable IEEE floating-point on Alpha
78	*/
79	#if defined(__alpha) && !defined(_IEEE_FP)
80	# if defined(TRIO_COMPILER_DECC)
81	# if defined(TRIO_PLATFORM_VMS)
82	# error "Must be compiled with option /IEEE_MODE=UNDERFLOW_TO_ZERO/FLOAT=IEEE"
83	# else
84	# if !defined(_CFE)
85	# error "Must be compiled with option -ieee"
86	# endif
87	# endif
88	# elif defined(TRIO_COMPILER_GCC) && (defined(__osf__) \|\| defined(__linux__))
89	# error "Must be compiled with option -mieee"
90	# endif
91	#endif /* __alpha && ! _IEEE_FP */
92
93	/*
94	* In ANSI/IEEE 754-1985 64-bits double format numbers have the
95	* following properties (amoungst others)
96	*
97	* o FLT_RADIX == 2: binary encoding
98	* o DBL_MAX_EXP == 1024: 11 bits exponent, where one bit is used
99	* to indicate special numbers (e.g. NaN and Infinity), so the
100	* maximum exponent is 10 bits wide (2^10 == 1024).
101	* o DBL_MANT_DIG == 53: The mantissa is 52 bits wide, but because
102	* numbers are normalized the initial binary 1 is represented
103	* implicitly (the so-called "hidden bit"), which leaves us with
104	* the ability to represent 53 bits wide mantissa.
105	*/
106	#if (FLT_RADIX == 2) && (DBL_MAX_EXP == 1024) && (DBL_MANT_DIG == 53)
107	# define USE_IEEE_754
108	#endif
109
110
111	/*************************************************************************
112	* Constants
113	*/
114
115	static TRIO_CONST char rcsid[] = "@(#)$Id: trionan.c 6076 2007-12-14 19:23:03Z vboxsync $";
116
117	#if defined(USE_IEEE_754)
118
119	/*
120	* Endian-agnostic indexing macro.
121	*
122	* The value of internalEndianMagic, when converted into a 64-bit
123	* integer, becomes 0x0706050403020100 (we could have used a 64-bit
124	* integer value instead of a double, but not all platforms supports
125	* that type). The value is automatically encoded with the correct
126	* endianess by the compiler, which means that we can support any
127	* kind of endianess. The individual bytes are then used as an index
128	* for the IEEE 754 bit-patterns and masks.
129	*/
130	#define TRIO_DOUBLE_INDEX(x) (((unsigned char *)&internalEndianMagic)[7-(x)])
131
132	static TRIO_CONST double internalEndianMagic = 7.949928895127363e-275;
133
134	/* Mask for the exponent */
135	static TRIO_CONST unsigned char ieee_754_exponent_mask[] = {
136	0x7F, 0xF0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
137	};
138
139	/* Mask for the mantissa */
140	static TRIO_CONST unsigned char ieee_754_mantissa_mask[] = {
141	0x00, 0x0F, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF
142	};
143
144	/* Mask for the sign bit */
145	static TRIO_CONST unsigned char ieee_754_sign_mask[] = {
146	0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
147	};
148
149	/* Bit-pattern for negative zero */
150	static TRIO_CONST unsigned char ieee_754_negzero_array[] = {
151	0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
152	};
153
154	/* Bit-pattern for infinity */
155	static TRIO_CONST unsigned char ieee_754_infinity_array[] = {
156	0x7F, 0xF0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
157	};
158
159	/* Bit-pattern for quiet NaN */
160	static TRIO_CONST unsigned char ieee_754_qnan_array[] = {
161	0x7F, 0xF8, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
162	};
163
164
165	/*************************************************************************
166	* Functions
167	*/
168
169	/*
170	* trio_make_double
171	*/
172	TRIO_PRIVATE double
173	trio_make_double
174	TRIO_ARGS1((values),
175	TRIO_CONST unsigned char *values)
176	{
177	TRIO_VOLATILE double result;
178	int i;
179
180	for (i = 0; i < (int)sizeof(double); i++) {
181	((TRIO_VOLATILE unsigned char *)&result)[TRIO_DOUBLE_INDEX(i)] = values[i];
182	}
183	return result;
184	}
185
186	/*
187	* trio_is_special_quantity
188	*/
189	TRIO_PRIVATE int
190	trio_is_special_quantity
191	TRIO_ARGS2((number, has_mantissa),
192	double number,
193	int *has_mantissa)
194	{
195	unsigned int i;
196	unsigned char current;
197	int is_special_quantity = TRIO_TRUE;
198
199	*has_mantissa = 0;
200
201	for (i = 0; i < (unsigned int)sizeof(double); i++) {
202	current = ((unsigned char *)&number)[TRIO_DOUBLE_INDEX(i)];
203	is_special_quantity
204	&= ((current & ieee_754_exponent_mask[i]) == ieee_754_exponent_mask[i]);
205	*has_mantissa \|= (current & ieee_754_mantissa_mask[i]);
206	}
207	return is_special_quantity;
208	}
209
210	/*
211	* trio_is_negative
212	*/
213	TRIO_PRIVATE int
214	trio_is_negative
215	TRIO_ARGS1((number),
216	double number)
217	{
218	unsigned int i;
219	int is_negative = TRIO_FALSE;
220
221	for (i = 0; i < (unsigned int)sizeof(double); i++) {
222	is_negative \|= (((unsigned char *)&number)[TRIO_DOUBLE_INDEX(i)]
223	& ieee_754_sign_mask[i]);
224	}
225	return is_negative;
226	}
227
228	#endif /* USE_IEEE_754 */
229
230
231	/**
232	Generate negative zero.
233
234	@return Floating-point representation of negative zero.
235	*/
236	TRIO_PUBLIC double
237	trio_nzero(TRIO_NOARGS)
238	{
239	#if defined(USE_IEEE_754)
240	return trio_make_double(ieee_754_negzero_array);
241	#else
242	TRIO_VOLATILE double zero = 0.0;
243
244	return -zero;
245	#endif
246	}
247
248	/**
249	Generate positive infinity.
250
251	@return Floating-point representation of positive infinity.
252	*/
253	TRIO_PUBLIC double
254	trio_pinf(TRIO_NOARGS)
255	{
256	/* Cache the result */
257	static double result = 0.0;
258
259	if (result == 0.0) {
260
261	#if defined(INFINITY) && defined(__STDC_IEC_559__)
262	result = (double)INFINITY;
263
264	#elif defined(USE_IEEE_754)
265	result = trio_make_double(ieee_754_infinity_array);
266
267	#else
268	/*
269	* If HUGE_VAL is different from DBL_MAX, then HUGE_VAL is used
270	* as infinity. Otherwise we have to resort to an overflow
271	* operation to generate infinity.
272	*/
273	# if defined(TRIO_PLATFORM_UNIX)
274	void (*signal_handler)(int) = signal(SIGFPE, SIG_IGN);
275	# endif
276
277	result = HUGE_VAL;
278	if (HUGE_VAL == DBL_MAX) {
279	/* Force overflow */
280	result += HUGE_VAL;
281	}
282
283	# if defined(TRIO_PLATFORM_UNIX)
284	signal(SIGFPE, signal_handler);
285	# endif
286
287	#endif
288	}
289	return result;
290	}
291
292	/**
293	Generate negative infinity.
294
295	@return Floating-point value of negative infinity.
296	*/
297	TRIO_PUBLIC double
298	trio_ninf(TRIO_NOARGS)
299	{
300	static double result = 0.0;
301
302	if (result == 0.0) {
303	/*
304	* Negative infinity is calculated by negating positive infinity,
305	* which can be done because it is legal to do calculations on
306	* infinity (for example, 1 / infinity == 0).
307	*/
308	result = -trio_pinf();
309	}
310	return result;
311	}
312
313	/**
314	Generate NaN.
315
316	@return Floating-point representation of NaN.
317	*/
318	TRIO_PUBLIC double
319	trio_nan(TRIO_NOARGS)
320	{
321	/* Cache the result */
322	static double result = 0.0;
323
324	if (result == 0.0) {
325
326	#if defined(TRIO_COMPILER_SUPPORTS_C99)
327	result = nan("");
328
329	#elif defined(NAN) && defined(__STDC_IEC_559__)
330	result = (double)NAN;
331
332	#elif defined(USE_IEEE_754)
333	result = trio_make_double(ieee_754_qnan_array);
334
335	#else
336	/*
337	* There are several ways to generate NaN. The one used here is
338	* to divide infinity by infinity. I would have preferred to add
339	* negative infinity to positive infinity, but that yields wrong
340	* result (infinity) on FreeBSD.
341	*
342	* This may fail if the hardware does not support NaN, or if
343	* the Invalid Operation floating-point exception is unmasked.
344	*/
345	# if defined(TRIO_PLATFORM_UNIX)
346	void (*signal_handler)(int) = signal(SIGFPE, SIG_IGN);
347	# endif
348
349	result = trio_pinf() / trio_pinf();
350
351	# if defined(TRIO_PLATFORM_UNIX)
352	signal(SIGFPE, signal_handler);
353	# endif
354
355	#endif
356	}
357	return result;
358	}
359
360	/**
361	Check for NaN.
362
363	@param number An arbitrary floating-point number.
364	@return Boolean value indicating whether or not the number is a NaN.
365	*/
366	TRIO_PUBLIC int
367	trio_isnan
368	TRIO_ARGS1((number),
369	double number)
370	{
371	#if (defined(TRIO_COMPILER_SUPPORTS_C99) && defined(isnan)) \
372	\|\| defined(TRIO_COMPILER_SUPPORTS_UNIX95)
373	/*
374	* C99 defines isnan() as a macro. UNIX95 defines isnan() as a
375	* function. This function was already present in XPG4, but this
376	* is a bit tricky to detect with compiler defines, so we choose
377	* the conservative approach and only use it for UNIX95.
378	*/
379	return isnan(number);
380
381	#elif defined(TRIO_COMPILER_MSVC) \|\| defined(TRIO_COMPILER_BCB)
382	/*
383	* Microsoft Visual C++ and Borland C++ Builder have an _isnan()
384	* function.
385	*/
386	return _isnan(number) ? TRIO_TRUE : TRIO_FALSE;
387
388	#elif defined(USE_IEEE_754)
389	/*
390	* Examine IEEE 754 bit-pattern. A NaN must have a special exponent
391	* pattern, and a non-empty mantissa.
392	*/
393	int has_mantissa;
394	int is_special_quantity;
395
396	is_special_quantity = trio_is_special_quantity(number, &has_mantissa);
397
398	return (is_special_quantity && has_mantissa);
399
400	#else
401	/*
402	* Fallback solution
403	*/
404	int status;
405	double integral, fraction;
406
407	# if defined(TRIO_PLATFORM_UNIX)
408	void (*signal_handler)(int) = signal(SIGFPE, SIG_IGN);
409	# endif
410
411	status = (/*
412	* NaN is the only number which does not compare to itself
413	*/
414	((TRIO_VOLATILE double)number != (TRIO_VOLATILE double)number) \|\|
415	/*
416	* Fallback solution if NaN compares to NaN
417	*/
418	((number != 0.0) &&
419	(fraction = modf(number, &integral),
420	integral == fraction)));
421
422	# if defined(TRIO_PLATFORM_UNIX)
423	signal(SIGFPE, signal_handler);
424	# endif
425
426	return status;
427
428	#endif
429	}
430
431	/**
432	Check for infinity.
433
434	@param number An arbitrary floating-point number.
435	@return 1 if positive infinity, -1 if negative infinity, 0 otherwise.
436	*/
437	TRIO_PUBLIC int
438	trio_isinf
439	TRIO_ARGS1((number),
440	double number)
441	{
442	#if defined(TRIO_COMPILER_DECC) && !defined(__linux__)
443	/*
444	* DECC has an isinf() macro, but it works differently than that
445	* of C99, so we use the fp_class() function instead.
446	*/
447	return ((fp_class(number) == FP_POS_INF)
448	? 1
449	: ((fp_class(number) == FP_NEG_INF) ? -1 : 0));
450
451	#elif defined(isinf)
452	/*
453	* C99 defines isinf() as a macro.
454	*/
455	return isinf(number)
456	? ((number > 0.0) ? 1 : -1)
457	: 0;
458
459	#elif defined(TRIO_COMPILER_MSVC) \|\| defined(TRIO_COMPILER_BCB)
460	/*
461	* Microsoft Visual C++ and Borland C++ Builder have an _fpclass()
462	* function that can be used to detect infinity.
463	*/
464	return ((_fpclass(number) == _FPCLASS_PINF)
465	? 1
466	: ((_fpclass(number) == _FPCLASS_NINF) ? -1 : 0));
467
468	#elif defined(USE_IEEE_754)
469	/*
470	* Examine IEEE 754 bit-pattern. Infinity must have a special exponent
471	* pattern, and an empty mantissa.
472	*/
473	int has_mantissa;
474	int is_special_quantity;
475
476	is_special_quantity = trio_is_special_quantity(number, &has_mantissa);
477
478	return (is_special_quantity && !has_mantissa)
479	? ((number < 0.0) ? -1 : 1)
480	: 0;
481
482	#else
483	/*
484	* Fallback solution.
485	*/
486	int status;
487
488	# if defined(TRIO_PLATFORM_UNIX)
489	void (*signal_handler)(int) = signal(SIGFPE, SIG_IGN);
490	# endif
491
492	double infinity = trio_pinf();
493
494	status = ((number == infinity)
495	? 1
496	: ((number == -infinity) ? -1 : 0));
497
498	# if defined(TRIO_PLATFORM_UNIX)
499	signal(SIGFPE, signal_handler);
500	# endif
501
502	return status;
503
504	#endif
505	}
506
507	#if 0
508	/* Temporary fix - this routine is not used anywhere */
509	/**
510	Check for finity.
511
512	@param number An arbitrary floating-point number.
513	@return Boolean value indicating whether or not the number is a finite.
514	*/
515	TRIO_PUBLIC int
516	trio_isfinite
517	TRIO_ARGS1((number),
518	double number)
519	{
520	#if defined(TRIO_COMPILER_SUPPORTS_C99) && defined(isfinite)
521	/*
522	* C99 defines isfinite() as a macro.
523	*/
524	return isfinite(number);
525
526	#elif defined(TRIO_COMPILER_MSVC) \|\| defined(TRIO_COMPILER_BCB)
527	/*
528	* Microsoft Visual C++ and Borland C++ Builder use _finite().
529	*/
530	return _finite(number);
531
532	#elif defined(USE_IEEE_754)
533	/*
534	* Examine IEEE 754 bit-pattern. For finity we do not care about the
535	* mantissa.
536	*/
537	int dummy;
538
539	return (! trio_is_special_quantity(number, &dummy));
540
541	#else
542	/*
543	* Fallback solution.
544	*/
545	return ((trio_isinf(number) == 0) && (trio_isnan(number) == 0));
546
547	#endif
548	}
549
550	#endif
551
552	/*
553	* The sign of NaN is always false
554	*/
555	TRIO_PUBLIC int
556	trio_fpclassify_and_signbit
557	TRIO_ARGS2((number, is_negative),
558	double number,
559	int *is_negative)
560	{
561	#if defined(fpclassify) && defined(signbit)
562	/*
563	* C99 defines fpclassify() and signbit() as a macros
564	*/
565	*is_negative = signbit(number);
566	switch (fpclassify(number)) {
567	case FP_NAN:
568	return TRIO_FP_NAN;
569	case FP_INFINITE:
570	return TRIO_FP_INFINITE;
571	case FP_SUBNORMAL:
572	return TRIO_FP_SUBNORMAL;
573	case FP_ZERO:
574	return TRIO_FP_ZERO;
575	default:
576	return TRIO_FP_NORMAL;
577	}
578
579	#else
580	# if defined(TRIO_COMPILER_DECC)
581	/*
582	* DECC has an fp_class() function.
583	*/
584	# define TRIO_FPCLASSIFY(n) fp_class(n)
585	# define TRIO_QUIET_NAN FP_QNAN
586	# define TRIO_SIGNALLING_NAN FP_SNAN
587	# define TRIO_POSITIVE_INFINITY FP_POS_INF
588	# define TRIO_NEGATIVE_INFINITY FP_NEG_INF
589	# define TRIO_POSITIVE_SUBNORMAL FP_POS_DENORM
590	# define TRIO_NEGATIVE_SUBNORMAL FP_NEG_DENORM
591	# define TRIO_POSITIVE_ZERO FP_POS_ZERO
592	# define TRIO_NEGATIVE_ZERO FP_NEG_ZERO
593	# define TRIO_POSITIVE_NORMAL FP_POS_NORM
594	# define TRIO_NEGATIVE_NORMAL FP_NEG_NORM
595
596	# elif defined(TRIO_COMPILER_MSVC) \|\| defined(TRIO_COMPILER_BCB)
597	/*
598	* Microsoft Visual C++ and Borland C++ Builder have an _fpclass()
599	* function.
600	*/
601	# define TRIO_FPCLASSIFY(n) _fpclass(n)
602	# define TRIO_QUIET_NAN _FPCLASS_QNAN
603	# define TRIO_SIGNALLING_NAN _FPCLASS_SNAN
604	# define TRIO_POSITIVE_INFINITY _FPCLASS_PINF
605	# define TRIO_NEGATIVE_INFINITY _FPCLASS_NINF
606	# define TRIO_POSITIVE_SUBNORMAL _FPCLASS_PD
607	# define TRIO_NEGATIVE_SUBNORMAL _FPCLASS_ND
608	# define TRIO_POSITIVE_ZERO _FPCLASS_PZ
609	# define TRIO_NEGATIVE_ZERO _FPCLASS_NZ
610	# define TRIO_POSITIVE_NORMAL _FPCLASS_PN
611	# define TRIO_NEGATIVE_NORMAL _FPCLASS_NN
612
613	# elif defined(FP_PLUS_NORM)
614	/*
615	* HP-UX 9.x and 10.x have an fpclassify() function, that is different
616	* from the C99 fpclassify() macro supported on HP-UX 11.x.
617	*
618	* AIX has class() for C, and _class() for C++, which returns the
619	* same values as the HP-UX fpclassify() function.
620	*/
621	# if defined(TRIO_PLATFORM_AIX)
622	# if defined(__cplusplus)
623	# define TRIO_FPCLASSIFY(n) _class(n)
624	# else
625	# define TRIO_FPCLASSIFY(n) class(n)
626	# endif
627	# else
628	# define TRIO_FPCLASSIFY(n) fpclassify(n)
629	# endif
630	# define TRIO_QUIET_NAN FP_QNAN
631	# define TRIO_SIGNALLING_NAN FP_SNAN
632	# define TRIO_POSITIVE_INFINITY FP_PLUS_INF
633	# define TRIO_NEGATIVE_INFINITY FP_MINUS_INF
634	# define TRIO_POSITIVE_SUBNORMAL FP_PLUS_DENORM
635	# define TRIO_NEGATIVE_SUBNORMAL FP_MINUS_DENORM
636	# define TRIO_POSITIVE_ZERO FP_PLUS_ZERO
637	# define TRIO_NEGATIVE_ZERO FP_MINUS_ZERO
638	# define TRIO_POSITIVE_NORMAL FP_PLUS_NORM
639	# define TRIO_NEGATIVE_NORMAL FP_MINUS_NORM
640	# endif
641
642	# if defined(TRIO_FPCLASSIFY)
643	switch (TRIO_FPCLASSIFY(number)) {
644	case TRIO_QUIET_NAN:
645	case TRIO_SIGNALLING_NAN:
646	is_negative = TRIO_FALSE; / NaN has no sign */
647	return TRIO_FP_NAN;
648	case TRIO_POSITIVE_INFINITY:
649	*is_negative = TRIO_FALSE;
650	return TRIO_FP_INFINITE;
651	case TRIO_NEGATIVE_INFINITY:
652	*is_negative = TRIO_TRUE;
653	return TRIO_FP_INFINITE;
654	case TRIO_POSITIVE_SUBNORMAL:
655	*is_negative = TRIO_FALSE;
656	return TRIO_FP_SUBNORMAL;
657	case TRIO_NEGATIVE_SUBNORMAL:
658	*is_negative = TRIO_TRUE;
659	return TRIO_FP_SUBNORMAL;
660	case TRIO_POSITIVE_ZERO:
661	*is_negative = TRIO_FALSE;
662	return TRIO_FP_ZERO;
663	case TRIO_NEGATIVE_ZERO:
664	*is_negative = TRIO_TRUE;
665	return TRIO_FP_ZERO;
666	case TRIO_POSITIVE_NORMAL:
667	*is_negative = TRIO_FALSE;
668	return TRIO_FP_NORMAL;
669	case TRIO_NEGATIVE_NORMAL:
670	*is_negative = TRIO_TRUE;
671	return TRIO_FP_NORMAL;
672	default:
673	/* Just in case... */
674	*is_negative = (number < 0.0);
675	return TRIO_FP_NORMAL;
676	}
677
678	# else
679	/*
680	* Fallback solution.
681	*/
682	int rc;
683
684	if (number == 0.0) {
685	/*
686	* In IEEE 754 the sign of zero is ignored in comparisons, so we
687	* have to handle this as a special case by examining the sign bit
688	* directly.
689	*/
690	# if defined(USE_IEEE_754)
691	*is_negative = trio_is_negative(number);
692	# else
693	is_negative = TRIO_FALSE; / FIXME */
694	# endif
695	return TRIO_FP_ZERO;
696	}
697	if (trio_isnan(number)) {
698	*is_negative = TRIO_FALSE;
699	return TRIO_FP_NAN;
700	}
701	if ((rc = trio_isinf(number))) {
702	*is_negative = (rc == -1);
703	return TRIO_FP_INFINITE;
704	}
705	if ((number > 0.0) && (number < DBL_MIN)) {
706	*is_negative = TRIO_FALSE;
707	return TRIO_FP_SUBNORMAL;
708	}
709	if ((number < 0.0) && (number > -DBL_MIN)) {
710	*is_negative = TRIO_TRUE;
711	return TRIO_FP_SUBNORMAL;
712	}
713	*is_negative = (number < 0.0);
714	return TRIO_FP_NORMAL;
715
716	# endif
717	#endif
718	}
719
720	/**
721	Examine the sign of a number.
722
723	@param number An arbitrary floating-point number.
724	@return Boolean value indicating whether or not the number has the
725	sign bit set (i.e. is negative).
726	*/
727	TRIO_PUBLIC int
728	trio_signbit
729	TRIO_ARGS1((number),
730	double number)
731	{
732	int is_negative;
733
734	(void)trio_fpclassify_and_signbit(number, &is_negative);
735	return is_negative;
736	}
737
738	#if 0
739	/* Temporary fix - this routine is not used in libxml */
740	/**
741	Examine the class of a number.
742
743	@param number An arbitrary floating-point number.
744	@return Enumerable value indicating the class of @p number
745	*/
746	TRIO_PUBLIC int
747	trio_fpclassify
748	TRIO_ARGS1((number),
749	double number)
750	{
751	int dummy;
752
753	return trio_fpclassify_and_signbit(number, &dummy);
754	}
755
756	#endif
757
758	/** @} SpecialQuantities */
759
760	/*************************************************************************
761	* For test purposes.
762	*
763	* Add the following compiler option to include this test code.
764	*
765	* Unix : -DSTANDALONE
766	* VMS : /DEFINE=(STANDALONE)
767	*/
768	#if defined(STANDALONE)
769	# include <stdio.h>
770
771	static TRIO_CONST char *
772	getClassification
773	TRIO_ARGS1((type),
774	int type)
775	{
776	switch (type) {
777	case TRIO_FP_INFINITE:
778	return "FP_INFINITE";
779	case TRIO_FP_NAN:
780	return "FP_NAN";
781	case TRIO_FP_NORMAL:
782	return "FP_NORMAL";
783	case TRIO_FP_SUBNORMAL:
784	return "FP_SUBNORMAL";
785	case TRIO_FP_ZERO:
786	return "FP_ZERO";
787	default:
788	return "FP_UNKNOWN";
789	}
790	}
791
792	static void
793	print_class
794	TRIO_ARGS2((prefix, number),
795	TRIO_CONST char *prefix,
796	double number)
797	{
798	printf("%-6s: %s %-15s %g\n",
799	prefix,
800	trio_signbit(number) ? "-" : "+",
801	getClassification(TRIO_FPCLASSIFY(number)),
802	number);
803	}
804
805	int main(TRIO_NOARGS)
806	{
807	double my_nan;
808	double my_pinf;
809	double my_ninf;
810	# if defined(TRIO_PLATFORM_UNIX)
811	void (*signal_handler) TRIO_PROTO((int));
812	# endif
813
814	my_nan = trio_nan();
815	my_pinf = trio_pinf();
816	my_ninf = trio_ninf();
817
818	print_class("Nan", my_nan);
819	print_class("PInf", my_pinf);
820	print_class("NInf", my_ninf);
821	print_class("PZero", 0.0);
822	print_class("NZero", -0.0);
823	print_class("PNorm", 1.0);
824	print_class("NNorm", -1.0);
825	print_class("PSub", 1.01e-307 - 1.00e-307);
826	print_class("NSub", 1.00e-307 - 1.01e-307);
827
828	printf("NaN : %4g 0x%02x%02x%02x%02x%02x%02x%02x%02x (%2d, %2d)\n",
829	my_nan,
830	((unsigned char *)&my_nan)[0],
831	((unsigned char *)&my_nan)[1],
832	((unsigned char *)&my_nan)[2],
833	((unsigned char *)&my_nan)[3],
834	((unsigned char *)&my_nan)[4],
835	((unsigned char *)&my_nan)[5],
836	((unsigned char *)&my_nan)[6],
837	((unsigned char *)&my_nan)[7],
838	trio_isnan(my_nan), trio_isinf(my_nan));
839	printf("PInf: %4g 0x%02x%02x%02x%02x%02x%02x%02x%02x (%2d, %2d)\n",
840	my_pinf,
841	((unsigned char *)&my_pinf)[0],
842	((unsigned char *)&my_pinf)[1],
843	((unsigned char *)&my_pinf)[2],
844	((unsigned char *)&my_pinf)[3],
845	((unsigned char *)&my_pinf)[4],
846	((unsigned char *)&my_pinf)[5],
847	((unsigned char *)&my_pinf)[6],
848	((unsigned char *)&my_pinf)[7],
849	trio_isnan(my_pinf), trio_isinf(my_pinf));
850	printf("NInf: %4g 0x%02x%02x%02x%02x%02x%02x%02x%02x (%2d, %2d)\n",
851	my_ninf,
852	((unsigned char *)&my_ninf)[0],
853	((unsigned char *)&my_ninf)[1],
854	((unsigned char *)&my_ninf)[2],
855	((unsigned char *)&my_ninf)[3],
856	((unsigned char *)&my_ninf)[4],
857	((unsigned char *)&my_ninf)[5],
858	((unsigned char *)&my_ninf)[6],
859	((unsigned char *)&my_ninf)[7],
860	trio_isnan(my_ninf), trio_isinf(my_ninf));
861
862	# if defined(TRIO_PLATFORM_UNIX)
863	signal_handler = signal(SIGFPE, SIG_IGN);
864	# endif
865
866	my_pinf = DBL_MAX + DBL_MAX;
867	my_ninf = -my_pinf;
868	my_nan = my_pinf / my_pinf;
869
870	# if defined(TRIO_PLATFORM_UNIX)
871	signal(SIGFPE, signal_handler);
872	# endif
873
874	printf("NaN : %4g 0x%02x%02x%02x%02x%02x%02x%02x%02x (%2d, %2d)\n",
875	my_nan,
876	((unsigned char *)&my_nan)[0],
877	((unsigned char *)&my_nan)[1],
878	((unsigned char *)&my_nan)[2],
879	((unsigned char *)&my_nan)[3],
880	((unsigned char *)&my_nan)[4],
881	((unsigned char *)&my_nan)[5],
882	((unsigned char *)&my_nan)[6],
883	((unsigned char *)&my_nan)[7],
884	trio_isnan(my_nan), trio_isinf(my_nan));
885	printf("PInf: %4g 0x%02x%02x%02x%02x%02x%02x%02x%02x (%2d, %2d)\n",
886	my_pinf,
887	((unsigned char *)&my_pinf)[0],
888	((unsigned char *)&my_pinf)[1],
889	((unsigned char *)&my_pinf)[2],
890	((unsigned char *)&my_pinf)[3],
891	((unsigned char *)&my_pinf)[4],
892	((unsigned char *)&my_pinf)[5],
893	((unsigned char *)&my_pinf)[6],
894	((unsigned char *)&my_pinf)[7],
895	trio_isnan(my_pinf), trio_isinf(my_pinf));
896	printf("NInf: %4g 0x%02x%02x%02x%02x%02x%02x%02x%02x (%2d, %2d)\n",
897	my_ninf,
898	((unsigned char *)&my_ninf)[0],
899	((unsigned char *)&my_ninf)[1],
900	((unsigned char *)&my_ninf)[2],
901	((unsigned char *)&my_ninf)[3],
902	((unsigned char *)&my_ninf)[4],
903	((unsigned char *)&my_ninf)[5],
904	((unsigned char *)&my_ninf)[6],
905	((unsigned char *)&my_ninf)[7],
906	trio_isnan(my_ninf), trio_isinf(my_ninf));
907
908	return 0;
909	}
910	#endif

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source: vbox/trunk/src/libs/libxml2-2.6.30/trionan.c@ 13571

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