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 * 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 "ieee754dp.h" 28 29 ieee754dp ieee754dp_mul(ieee754dp x, ieee754dp y) 30 { 31 COMPXDP; 32 COMPYDP; 33 34 EXPLODEXDP; 35 EXPLODEYDP; 36 37 CLEARCX; 38 39 FLUSHXDP; 40 FLUSHYDP; 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 ieee754dp_nanxcpt(ieee754dp_indef(), "mul", 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 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO): 74 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF): 75 SETCX(IEEE754_INVALID_OPERATION); 76 return ieee754dp_xcpt(ieee754dp_indef(), "mul", x, y); 77 78 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF): 79 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF): 80 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM): 81 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM): 82 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF): 83 return ieee754dp_inf(xs ^ ys); 84 85 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO): 86 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM): 87 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM): 88 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO): 89 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO): 90 return ieee754dp_zero(xs ^ ys); 91 92 93 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM): 94 DPDNORMX; 95 96 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM): 97 DPDNORMY; 98 break; 99 100 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM): 101 DPDNORMX; 102 break; 103 104 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_NORM): 105 break; 106 } 107 /* rm = xm * ym, re = xe+ye basically */ 108 assert(xm & DP_HIDDEN_BIT); 109 assert(ym & DP_HIDDEN_BIT); 110 { 111 int re = xe + ye; 112 int rs = xs ^ ys; 113 u64 rm; 114 115 /* shunt to top of word */ 116 xm <<= 64 - (DP_MBITS + 1); 117 ym <<= 64 - (DP_MBITS + 1); 118 119 /* multiply 32bits xm,ym to give high 32bits rm with stickness 120 */ 121 122 /* 32 * 32 => 64 */ 123 #define DPXMULT(x, y) ((u64)(x) * (u64)y) 124 125 { 126 unsigned lxm = xm; 127 unsigned hxm = xm >> 32; 128 unsigned lym = ym; 129 unsigned hym = ym >> 32; 130 u64 lrm; 131 u64 hrm; 132 133 lrm = DPXMULT(lxm, lym); 134 hrm = DPXMULT(hxm, hym); 135 136 { 137 u64 t = DPXMULT(lxm, hym); 138 { 139 u64 at = 140 lrm + (t << 32); 141 hrm += at < lrm; 142 lrm = at; 143 } 144 hrm = hrm + (t >> 32); 145 } 146 147 { 148 u64 t = DPXMULT(hxm, lym); 149 { 150 u64 at = 151 lrm + (t << 32); 152 hrm += at < lrm; 153 lrm = at; 154 } 155 hrm = hrm + (t >> 32); 156 } 157 rm = hrm | (lrm != 0); 158 } 159 160 /* 161 * sticky shift down to normal rounding precision 162 */ 163 if ((s64) rm < 0) { 164 rm = 165 (rm >> (64 - (DP_MBITS + 1 + 3))) | 166 ((rm << (DP_MBITS + 1 + 3)) != 0); 167 re++; 168 } else { 169 rm = 170 (rm >> (64 - (DP_MBITS + 1 + 3 + 1))) | 171 ((rm << (DP_MBITS + 1 + 3 + 1)) != 0); 172 } 173 assert(rm & (DP_HIDDEN_BIT << 3)); 174 DPNORMRET2(rs, re, rm, "mul", x, y); 175 } 176 } 177