1 /* IEEE754 floating point arithmetic 2 * double precision: common utilities 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 "ieee754dp.h" 29 30 ieee754dp ieee754dp_mul(ieee754dp x, ieee754dp y) 31 { 32 COMPXDP; 33 COMPYDP; 34 35 EXPLODEXDP; 36 EXPLODEYDP; 37 38 CLEARCX; 39 40 FLUSHXDP; 41 FLUSHYDP; 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 ieee754dp_nanxcpt(ieee754dp_indef(), "mul", 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 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO): 75 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF): 76 SETCX(IEEE754_INVALID_OPERATION); 77 return ieee754dp_xcpt(ieee754dp_indef(), "mul", x, y); 78 79 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF): 80 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF): 81 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM): 82 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM): 83 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF): 84 return ieee754dp_inf(xs ^ ys); 85 86 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO): 87 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM): 88 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM): 89 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO): 90 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO): 91 return ieee754dp_zero(xs ^ ys); 92 93 94 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM): 95 DPDNORMX; 96 97 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM): 98 DPDNORMY; 99 break; 100 101 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM): 102 DPDNORMX; 103 break; 104 105 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_NORM): 106 break; 107 } 108 /* rm = xm * ym, re = xe+ye basicly */ 109 assert(xm & DP_HIDDEN_BIT); 110 assert(ym & DP_HIDDEN_BIT); 111 { 112 int re = xe + ye; 113 int rs = xs ^ ys; 114 u64 rm; 115 116 /* shunt to top of word */ 117 xm <<= 64 - (DP_MBITS + 1); 118 ym <<= 64 - (DP_MBITS + 1); 119 120 /* multiply 32bits xm,ym to give high 32bits rm with stickness 121 */ 122 123 /* 32 * 32 => 64 */ 124 #define DPXMULT(x,y) ((u64)(x) * (u64)y) 125 126 { 127 unsigned lxm = xm; 128 unsigned hxm = xm >> 32; 129 unsigned lym = ym; 130 unsigned hym = ym >> 32; 131 u64 lrm; 132 u64 hrm; 133 134 lrm = DPXMULT(lxm, lym); 135 hrm = DPXMULT(hxm, hym); 136 137 { 138 u64 t = DPXMULT(lxm, hym); 139 { 140 u64 at = 141 lrm + (t << 32); 142 hrm += at < lrm; 143 lrm = at; 144 } 145 hrm = hrm + (t >> 32); 146 } 147 148 { 149 u64 t = DPXMULT(hxm, lym); 150 { 151 u64 at = 152 lrm + (t << 32); 153 hrm += at < lrm; 154 lrm = at; 155 } 156 hrm = hrm + (t >> 32); 157 } 158 rm = hrm | (lrm != 0); 159 } 160 161 /* 162 * sticky shift down to normal rounding precision 163 */ 164 if ((s64) rm < 0) { 165 rm = 166 (rm >> (64 - (DP_MBITS + 1 + 3))) | 167 ((rm << (DP_MBITS + 1 + 3)) != 0); 168 re++; 169 } else { 170 rm = 171 (rm >> (64 - (DP_MBITS + 1 + 3 + 1))) | 172 ((rm << (DP_MBITS + 1 + 3 + 1)) != 0); 173 } 174 assert(rm & (DP_HIDDEN_BIT << 3)); 175 DPNORMRET2(rs, re, rm, "mul", x, y); 176 } 177 } 178