1 /* IEEE754 floating point arithmetic 2 * single precision 3 */ 4 /* 5 * MIPS floating point support 6 * Copyright (C) 1994-2000 Algorithmics Ltd. 7 * http://www.algor.co.uk 8 * 9 * ######################################################################## 10 * 11 * This program is free software; you can distribute it and/or modify it 12 * under the terms of the GNU General Public License (Version 2) as 13 * published by the Free Software Foundation. 14 * 15 * This program is distributed in the hope it will be useful, but WITHOUT 16 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 17 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 18 * for more details. 19 * 20 * You should have received a copy of the GNU General Public License along 21 * with this program; if not, write to the Free Software Foundation, Inc., 22 * 59 Temple Place - Suite 330, Boston MA 02111-1307, USA. 23 * 24 * ######################################################################## 25 */ 26 27 28 #include "ieee754sp.h" 29 30 ieee754sp ieee754sp_div(ieee754sp x, ieee754sp y) 31 { 32 COMPXSP; 33 COMPYSP; 34 35 EXPLODEXSP; 36 EXPLODEYSP; 37 38 CLEARCX; 39 40 FLUSHXSP; 41 FLUSHYSP; 42 43 switch (CLPAIR(xc, yc)) { 44 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_QNAN): 45 case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_SNAN): 46 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_SNAN): 47 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_SNAN): 48 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_SNAN): 49 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_SNAN): 50 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_SNAN): 51 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_ZERO): 52 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_NORM): 53 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_DNORM): 54 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_INF): 55 SETCX(IEEE754_INVALID_OPERATION); 56 return ieee754sp_nanxcpt(ieee754sp_indef(), "div", x, y); 57 58 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_QNAN): 59 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_QNAN): 60 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_QNAN): 61 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_QNAN): 62 return y; 63 64 case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_QNAN): 65 case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_ZERO): 66 case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_NORM): 67 case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_DNORM): 68 case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_INF): 69 return x; 70 71 72 /* Infinity handling 73 */ 74 75 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF): 76 SETCX(IEEE754_INVALID_OPERATION); 77 return ieee754sp_xcpt(ieee754sp_indef(), "div", x, y); 78 79 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF): 80 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF): 81 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF): 82 return ieee754sp_zero(xs ^ ys); 83 84 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO): 85 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM): 86 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM): 87 return ieee754sp_inf(xs ^ ys); 88 89 /* Zero handling 90 */ 91 92 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO): 93 SETCX(IEEE754_INVALID_OPERATION); 94 return ieee754sp_xcpt(ieee754sp_indef(), "div", x, y); 95 96 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO): 97 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO): 98 SETCX(IEEE754_ZERO_DIVIDE); 99 return ieee754sp_xcpt(ieee754sp_inf(xs ^ ys), "div", x, y); 100 101 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM): 102 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM): 103 return ieee754sp_zero(xs == ys ? 0 : 1); 104 105 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM): 106 SPDNORMX; 107 108 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM): 109 SPDNORMY; 110 break; 111 112 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM): 113 SPDNORMX; 114 break; 115 116 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_NORM): 117 break; 118 } 119 assert(xm & SP_HIDDEN_BIT); 120 assert(ym & SP_HIDDEN_BIT); 121 122 /* provide rounding space */ 123 xm <<= 3; 124 ym <<= 3; 125 126 { 127 /* now the dirty work */ 128 129 unsigned rm = 0; 130 int re = xe - ye; 131 unsigned bm; 132 133 for (bm = SP_MBIT(SP_MBITS + 2); bm; bm >>= 1) { 134 if (xm >= ym) { 135 xm -= ym; 136 rm |= bm; 137 if (xm == 0) 138 break; 139 } 140 xm <<= 1; 141 } 142 rm <<= 1; 143 if (xm) 144 rm |= 1; /* have remainder, set sticky */ 145 146 assert(rm); 147 148 /* normalise rm to rounding precision ? 149 */ 150 while ((rm >> (SP_MBITS + 3)) == 0) { 151 rm <<= 1; 152 re--; 153 } 154 155 SPNORMRET2(xs == ys ? 0 : 1, re, rm, "div", x, y); 156 } 157 } 158