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