1/**************************************************************** 2 3The author of this software is David M. Gay. 4 5Copyright (C) 2005 by David M. Gay 6All Rights Reserved 7 8Permission to use, copy, modify, and distribute this software and its 9documentation for any purpose and without fee is hereby granted, 10provided that the above copyright notice appear in all copies and that 11both that the copyright notice and this permission notice and warranty 12disclaimer appear in supporting documentation, and that the name of 13the author or any of his current or former employers not be used in 14advertising or publicity pertaining to distribution of the software 15without specific, written prior permission. 16 17THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, 18INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN 19NO EVENT SHALL THE AUTHOR OR ANY OF HIS CURRENT OR FORMER EMPLOYERS BE 20LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY 21DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, 22WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, 23ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS 24SOFTWARE. 25 26****************************************************************/ 27 28/* Please send bug reports to David M. Gay (dmg at acm dot org, 29 * with " at " changed at "@" and " dot " changed to "."). */ 30 31/* Program to compute quiet NaNs of various precisions (float, */ 32/* double, and perhaps long double) on the current system, */ 33/* provided the system uses binary IEEE (P754) arithmetic. */ 34/* Note that one system's quiet NaN may be a signaling NaN on */ 35/* another system. The IEEE arithmetic standards (P754, P854) */ 36/* do not specify how to distinguish signaling NaNs from quiet */ 37/* ones, and this detail varies across systems. The computed */ 38/* NaN values are encoded in #defines for values for an */ 39/* unsigned 32-bit integer type, called Ulong below, and */ 40/* (for long double) perhaps as unsigned short values. Once */ 41/* upon a time, there were PC compilers for Intel CPUs that */ 42/* had sizeof(long double) = 10. Are such compilers still */ 43/* distributed? */ 44 45#include <stdio.h> 46#include "arith.h" 47 48#ifndef Long 49#define Long long 50#endif 51 52typedef unsigned Long Ulong; 53 54#undef HAVE_IEEE 55#ifdef IEEE_8087 56#define _0 1 57#define _1 0 58#define HAVE_IEEE 59#endif 60#ifdef IEEE_MC68k 61#define _0 0 62#define _1 1 63#define HAVE_IEEE 64#endif 65 66#define UL (unsigned long) 67 68 int 69main(void) 70{ 71#ifdef HAVE_IEEE 72 typedef union { 73 float f; 74 double d; 75 Ulong L[4]; 76#ifndef NO_LONG_LONG 77 unsigned short u[5]; 78 long double D; 79#endif 80 } U; 81 U a, b, c; 82 int i; 83 84 a.L[0] = b.L[0] = 0x7f800000; 85 c.f = a.f - b.f; 86 printf("#define f_QNAN 0x%lx\n", UL c.L[0]); 87 a.L[_0] = b.L[_0] = 0x7ff00000; 88 a.L[_1] = b.L[_1] = 0; 89 c.d = a.d - b.d; /* quiet NaN */ 90 printf("#define d_QNAN0 0x%lx\n", UL c.L[0]); 91 printf("#define d_QNAN1 0x%lx\n", UL c.L[1]); 92#ifdef NO_LONG_LONG 93 for(i = 0; i < 4; i++) 94 printf("#define ld_QNAN%d 0xffffffff\n", i); 95 for(i = 0; i < 5; i++) 96 printf("#define ldus_QNAN%d 0xffff\n", i); 97#else 98 b.D = c.D = a.d; 99 if (printf("") < 0) 100 c.D = 37; /* never executed; just defeat optimization */ 101 a.L[2] = a.L[3] = 0; 102 a.D = b.D - c.D; 103 for(i = 0; i < 4; i++) 104 printf("#define ld_QNAN%d 0x%lx\n", i, UL a.L[i]); 105 for(i = 0; i < 5; i++) 106 printf("#define ldus_QNAN%d 0x%x\n", i, a.u[i]); 107#endif 108#endif /* HAVE_IEEE */ 109 return 0; 110 } 111