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111 lines
3.3 KiB
C
111 lines
3.3 KiB
C
/****************************************************************
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The author of this software is David M. Gay.
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Copyright (C) 2005 by David M. Gay
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All Rights Reserved
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Permission to use, copy, modify, and distribute this software and its
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documentation for any purpose and without fee is hereby granted,
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provided that the above copyright notice appear in all copies and that
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both that the copyright notice and this permission notice and warranty
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disclaimer appear in supporting documentation, and that the name of
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the author or any of his current or former employers not be used in
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advertising or publicity pertaining to distribution of the software
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without specific, written prior permission.
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THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
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INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN
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NO EVENT SHALL THE AUTHOR OR ANY OF HIS CURRENT OR FORMER EMPLOYERS BE
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LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY
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DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
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WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
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ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
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SOFTWARE.
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****************************************************************/
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/* Please send bug reports to David M. Gay (dmg at acm dot org,
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* with " at " changed at "@" and " dot " changed to "."). */
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/* Program to compute quiet NaNs of various precisions (float, */
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/* double, and perhaps long double) on the current system, */
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/* provided the system uses binary IEEE (P754) arithmetic. */
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/* Note that one system's quiet NaN may be a signaling NaN on */
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/* another system. The IEEE arithmetic standards (P754, P854) */
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/* do not specify how to distinguish signaling NaNs from quiet */
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/* ones, and this detail varies across systems. The computed */
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/* NaN values are encoded in #defines for values for an */
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/* unsigned 32-bit integer type, called Ulong below, and */
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/* (for long double) perhaps as unsigned short values. Once */
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/* upon a time, there were PC compilers for Intel CPUs that */
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/* had sizeof(long double) = 10. Are such compilers still */
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/* distributed? */
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#include <stdio.h>
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#include "arith.h"
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#ifndef Long
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#define Long long
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#endif
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typedef unsigned Long Ulong;
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#undef HAVE_IEEE
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#ifdef IEEE_8087
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#define _0 1
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#define _1 0
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#define HAVE_IEEE
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#endif
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#ifdef IEEE_MC68k
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#define _0 0
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#define _1 1
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#define HAVE_IEEE
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#endif
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#define UL (unsigned long)
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int
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main(void)
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{
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#ifdef HAVE_IEEE
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typedef union {
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float f;
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double d;
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Ulong L[4];
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#ifndef NO_LONG_LONG
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unsigned short u[5];
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long double D;
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#endif
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} U;
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U a, b, c;
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int i;
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a.L[0] = b.L[0] = 0x7f800000;
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c.f = a.f - b.f;
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printf("#define f_QNAN 0x%lx\n", UL c.L[0]);
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a.L[_0] = b.L[_0] = 0x7ff00000;
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a.L[_1] = b.L[_1] = 0;
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c.d = a.d - b.d; /* quiet NaN */
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printf("#define d_QNAN0 0x%lx\n", UL c.L[0]);
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printf("#define d_QNAN1 0x%lx\n", UL c.L[1]);
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#ifdef NO_LONG_LONG
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for(i = 0; i < 4; i++)
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printf("#define ld_QNAN%d 0xffffffff\n", i);
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for(i = 0; i < 5; i++)
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printf("#define ldus_QNAN%d 0xffff\n", i);
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#else
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b.D = c.D = a.d;
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if (printf("") < 0)
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c.D = 37; /* never executed; just defeat optimization */
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a.L[2] = a.L[3] = 0;
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a.D = b.D - c.D;
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for(i = 0; i < 4; i++)
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printf("#define ld_QNAN%d 0x%lx\n", i, UL a.L[i]);
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for(i = 0; i < 5; i++)
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printf("#define ldus_QNAN%d 0x%x\n", i, a.u[i]);
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#endif
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#endif /* HAVE_IEEE */
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return 0;
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}
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