1 /* $NetBSD: g_ddfmt.c,v 1.1.1.1 2006/01/25 15:18:44 kleink Exp $ */ 2 3 /**************************************************************** 4 5 The author of this software is David M. Gay. 6 7 Copyright (C) 1998 by Lucent Technologies 8 All Rights Reserved 9 10 Permission to use, copy, modify, and distribute this software and 11 its documentation for any purpose and without fee is hereby 12 granted, provided that the above copyright notice appear in all 13 copies and that both that the copyright notice and this 14 permission notice and warranty disclaimer appear in supporting 15 documentation, and that the name of Lucent or any of its entities 16 not be used in advertising or publicity pertaining to 17 distribution of the software without specific, written prior 18 permission. 19 20 LUCENT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, 21 INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. 22 IN NO EVENT SHALL LUCENT OR ANY OF ITS ENTITIES BE LIABLE FOR ANY 23 SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 24 WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER 25 IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, 26 ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF 27 THIS SOFTWARE. 28 29 ****************************************************************/ 30 31 /* Please send bug reports to David M. Gay (dmg@acm.org). */ 32 33 #include "gdtoaimp.h" 34 #include <string.h> 35 36 char * 37 #ifdef KR_headers 38 g_ddfmt(buf, dd, ndig, bufsize) char *buf; double *dd; int ndig; unsigned bufsize; 39 #else 40 g_ddfmt(char *buf, double *dd, int ndig, unsigned bufsize) 41 #endif 42 { 43 FPI fpi; 44 char *b, *s, *se; 45 ULong *L, bits0[4], *bits, *zx; 46 int bx, by, decpt, ex, ey, i, j, mode; 47 Bigint *x, *y, *z; 48 double ddx[2]; 49 50 if (bufsize < 10 || bufsize < ndig + 8) 51 return 0; 52 53 L = (ULong*)dd; 54 if ((L[_0] & 0x7ff00000L) == 0x7ff00000L) { 55 /* Infinity or NaN */ 56 if (L[_0] & 0xfffff || L[_1]) { 57 nanret: 58 return strcp(buf, "NaN"); 59 } 60 if ((L[2+_0] & 0x7ff00000) == 0x7ff00000) { 61 if (L[2+_0] & 0xfffff || L[2+_1]) 62 goto nanret; 63 if ((L[_0] ^ L[2+_0]) & 0x80000000L) 64 goto nanret; /* Infinity - Infinity */ 65 } 66 infret: 67 b = buf; 68 if (L[_0] & 0x80000000L) 69 *b++ = '-'; 70 return strcp(b, "Infinity"); 71 } 72 if ((L[2+_0] & 0x7ff00000) == 0x7ff00000) { 73 L += 2; 74 if (L[_0] & 0xfffff || L[_1]) 75 goto nanret; 76 goto infret; 77 } 78 if (dd[0] + dd[1] == 0.) { 79 b = buf; 80 #ifndef IGNORE_ZERO_SIGN 81 if (L[_0] & L[2+_0] & 0x80000000L) 82 *b++ = '-'; 83 #endif 84 *b++ = '0'; 85 *b = 0; 86 return b; 87 } 88 if ((L[_0] & 0x7ff00000L) < (L[2+_0] & 0x7ff00000L)) { 89 ddx[1] = dd[0]; 90 ddx[0] = dd[1]; 91 dd = ddx; 92 L = (ULong*)dd; 93 } 94 z = d2b(dd[0], &ex, &bx); 95 if (dd[1] == 0.) 96 goto no_y; 97 x = z; 98 y = d2b(dd[1], &ey, &by); 99 if ( (i = ex - ey) !=0) { 100 if (i > 0) { 101 x = lshift(x, i); 102 ex = ey; 103 } 104 else 105 y = lshift(y, -i); 106 } 107 if ((L[_0] ^ L[2+_0]) & 0x80000000L) { 108 z = diff(x, y); 109 if (L[_0] & 0x80000000L) 110 z->sign = 1 - z->sign; 111 } 112 else { 113 z = sum(x, y); 114 if (L[_0] & 0x80000000L) 115 z->sign = 1; 116 } 117 Bfree(x); 118 Bfree(y); 119 no_y: 120 bits = zx = z->x; 121 for(i = 0; !*zx; zx++) 122 i += 32; 123 i += lo0bits(zx); 124 if (i) { 125 rshift(z, i); 126 ex += i; 127 } 128 fpi.nbits = z->wds * 32 - hi0bits(z->x[j = z->wds-1]); 129 if (fpi.nbits < 106) { 130 fpi.nbits = 106; 131 if (j < 3) { 132 for(i = 0; i <= j; i++) 133 bits0[i] = bits[i]; 134 while(i < 4) 135 bits0[i++] = 0; 136 bits = bits0; 137 } 138 } 139 mode = 2; 140 if (ndig <= 0) { 141 if (bufsize < (int)(fpi.nbits * .301029995664) + 10) { 142 Bfree(z); 143 return 0; 144 } 145 mode = 0; 146 } 147 fpi.emin = 1-1023-53+1; 148 fpi.emax = 2046-1023-106+1; 149 fpi.rounding = FPI_Round_near; 150 fpi.sudden_underflow = 0; 151 i = STRTOG_Normal; 152 s = gdtoa(&fpi, ex, bits, &i, mode, ndig, &decpt, &se); 153 b = g__fmt(buf, s, se, decpt, z->sign); 154 Bfree(z); 155 return b; 156 } 157