1 /**************************************************************** 2 3 The author of this software is David M. Gay. 4 5 Copyright (C) 1998 by Lucent Technologies 6 All Rights Reserved 7 8 Permission to use, copy, modify, and distribute this software and 9 its documentation for any purpose and without fee is hereby 10 granted, provided that the above copyright notice appear in all 11 copies and that both that the copyright notice and this 12 permission notice and warranty disclaimer appear in supporting 13 documentation, and that the name of Lucent or any of its entities 14 not be used in advertising or publicity pertaining to 15 distribution of the software without specific, written prior 16 permission. 17 18 LUCENT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, 19 INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. 20 IN NO EVENT SHALL LUCENT OR ANY OF ITS ENTITIES BE LIABLE FOR ANY 21 SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 22 WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER 23 IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, 24 ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF 25 THIS SOFTWARE. 26 27 ****************************************************************/ 28 29 /* Please send bug reports to David M. Gay (dmg@acm.org). */ 30 31 #include "gdtoaimp.h" 32 #include <string.h> 33 34 char * 35 #ifdef KR_headers 36 g_ddfmt(buf, dd0, ndig, bufsize) char *buf; double *dd0; int ndig; size_t bufsize; 37 #else 38 g_ddfmt(char *buf, double *dd0, int ndig, size_t bufsize) 39 #endif 40 { 41 FPI fpi; 42 char *b, *s, *se; 43 ULong *L, bits0[4], *bits, *zx; 44 int bx, by, decpt, ex, ey, i, j, mode; 45 Bigint *x, *y, *z; 46 U *dd, ddx[2]; 47 #ifdef Honor_FLT_ROUNDS /*{{*/ 48 int Rounding; 49 #ifdef Trust_FLT_ROUNDS /*{{ only define this if FLT_ROUNDS really works! */ 50 Rounding = Flt_Rounds; 51 #else /*}{*/ 52 Rounding = 1; 53 switch(fegetround()) { 54 case FE_TOWARDZERO: Rounding = 0; break; 55 case FE_UPWARD: Rounding = 2; break; 56 case FE_DOWNWARD: Rounding = 3; 57 } 58 #endif /*}}*/ 59 #else /*}{*/ 60 #define Rounding FPI_Round_near 61 #endif /*}}*/ 62 63 if (bufsize < 10 || bufsize < ndig + 8) 64 return 0; 65 66 dd = (U*)dd0; 67 L = dd->L; 68 if ((L[_0] & 0x7ff00000L) == 0x7ff00000L) { 69 /* Infinity or NaN */ 70 if (L[_0] & 0xfffff || L[_1]) { 71 nanret: 72 return strcp(buf, "NaN"); 73 } 74 if ((L[2+_0] & 0x7ff00000) == 0x7ff00000) { 75 if (L[2+_0] & 0xfffff || L[2+_1]) 76 goto nanret; 77 if ((L[_0] ^ L[2+_0]) & 0x80000000L) 78 goto nanret; /* Infinity - Infinity */ 79 } 80 infret: 81 b = buf; 82 if (L[_0] & 0x80000000L) 83 *b++ = '-'; 84 return strcp(b, "Infinity"); 85 } 86 if ((L[2+_0] & 0x7ff00000) == 0x7ff00000) { 87 L += 2; 88 if (L[_0] & 0xfffff || L[_1]) 89 goto nanret; 90 goto infret; 91 } 92 if (dval(&dd[0]) + dval(&dd[1]) == 0.) { 93 b = buf; 94 #ifndef IGNORE_ZERO_SIGN 95 if (L[_0] & L[2+_0] & 0x80000000L) 96 *b++ = '-'; 97 #endif 98 *b++ = '0'; 99 *b = 0; 100 return b; 101 } 102 if ((L[_0] & 0x7ff00000L) < (L[2+_0] & 0x7ff00000L)) { 103 dval(&ddx[1]) = dval(&dd[0]); 104 dval(&ddx[0]) = dval(&dd[1]); 105 dd = ddx; 106 L = dd->L; 107 } 108 z = d2b(dval(&dd[0]), &ex, &bx); 109 if (dval(&dd[1]) == 0.) 110 goto no_y; 111 x = z; 112 y = d2b(dval(&dd[1]), &ey, &by); 113 if ( (i = ex - ey) !=0) { 114 if (i > 0) { 115 x = lshift(x, i); 116 ex = ey; 117 } 118 else 119 y = lshift(y, -i); 120 } 121 if ((L[_0] ^ L[2+_0]) & 0x80000000L) { 122 z = diff(x, y); 123 if (L[_0] & 0x80000000L) 124 z->sign = 1 - z->sign; 125 } 126 else { 127 z = sum(x, y); 128 if (L[_0] & 0x80000000L) 129 z->sign = 1; 130 } 131 Bfree(x); 132 Bfree(y); 133 no_y: 134 bits = zx = z->x; 135 for(i = 0; !*zx; zx++) 136 i += 32; 137 i += lo0bits(zx); 138 if (i) { 139 rshift(z, i); 140 ex += i; 141 } 142 fpi.nbits = z->wds * 32 - hi0bits(z->x[j = z->wds-1]); 143 if (fpi.nbits < 106) { 144 fpi.nbits = 106; 145 if (j < 3) { 146 for(i = 0; i <= j; i++) 147 bits0[i] = bits[i]; 148 while(i < 4) 149 bits0[i++] = 0; 150 bits = bits0; 151 } 152 } 153 mode = 2; 154 if (ndig <= 0) { 155 if (bufsize < (int)(fpi.nbits * .301029995664) + 10) { 156 Bfree(z); 157 return 0; 158 } 159 mode = 0; 160 } 161 fpi.emin = 1-1023-53+1; 162 fpi.emax = 2046-1023-106+1; 163 fpi.rounding = Rounding; 164 fpi.sudden_underflow = 0; 165 i = STRTOG_Normal; 166 s = gdtoa(&fpi, ex, bits, &i, mode, ndig, &decpt, &se); 167 b = g__fmt(buf, s, se, decpt, z->sign, bufsize); 168 Bfree(z); 169 return b; 170 } 171