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 * This program is free software; you can distribute it and/or modify it 9 * under the terms of the GNU General Public License (Version 2) as 10 * published by the Free Software Foundation. 11 * 12 * This program is distributed in the hope it will be useful, but WITHOUT 13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 14 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 15 * for more details. 16 * 17 * You should have received a copy of the GNU General Public License along 18 * with this program; if not, write to the Free Software Foundation, Inc., 19 * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 */ 21 22 #include "ieee754dp.h" 23 24 union ieee754dp ieee754dp_mul(union ieee754dp x, union ieee754dp y) 25 { 26 int re; 27 int rs; 28 u64 rm; 29 unsigned lxm; 30 unsigned hxm; 31 unsigned lym; 32 unsigned hym; 33 u64 lrm; 34 u64 hrm; 35 u64 t; 36 u64 at; 37 38 COMPXDP; 39 COMPYDP; 40 41 EXPLODEXDP; 42 EXPLODEYDP; 43 44 ieee754_clearcx(); 45 46 FLUSHXDP; 47 FLUSHYDP; 48 49 switch (CLPAIR(xc, yc)) { 50 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_QNAN): 51 case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_SNAN): 52 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_SNAN): 53 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_SNAN): 54 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_SNAN): 55 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_SNAN): 56 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_SNAN): 57 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_ZERO): 58 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_NORM): 59 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_DNORM): 60 case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_INF): 61 ieee754_setcx(IEEE754_INVALID_OPERATION); 62 return ieee754dp_nanxcpt(ieee754dp_indef()); 63 64 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_QNAN): 65 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_QNAN): 66 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_QNAN): 67 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_QNAN): 68 return y; 69 70 case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_QNAN): 71 case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_ZERO): 72 case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_NORM): 73 case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_DNORM): 74 case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_INF): 75 return x; 76 77 78 /* 79 * Infinity handling 80 */ 81 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO): 82 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF): 83 ieee754_setcx(IEEE754_INVALID_OPERATION); 84 return ieee754dp_indef(); 85 86 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF): 87 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF): 88 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM): 89 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM): 90 case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF): 91 return ieee754dp_inf(xs ^ ys); 92 93 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO): 94 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM): 95 case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM): 96 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO): 97 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO): 98 return ieee754dp_zero(xs ^ ys); 99 100 101 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM): 102 DPDNORMX; 103 104 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM): 105 DPDNORMY; 106 break; 107 108 case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM): 109 DPDNORMX; 110 break; 111 112 case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_NORM): 113 break; 114 } 115 /* rm = xm * ym, re = xe+ye basically */ 116 assert(xm & DP_HIDDEN_BIT); 117 assert(ym & DP_HIDDEN_BIT); 118 119 re = xe + ye; 120 rs = xs ^ ys; 121 122 /* shunt to top of word */ 123 xm <<= 64 - (DP_FBITS + 1); 124 ym <<= 64 - (DP_FBITS + 1); 125 126 /* 127 * Multiply 32 bits xm, ym to give high 32 bits rm with stickness. 128 */ 129 130 /* 32 * 32 => 64 */ 131 #define DPXMULT(x, y) ((u64)(x) * (u64)y) 132 133 lxm = xm; 134 hxm = xm >> 32; 135 lym = ym; 136 hym = ym >> 32; 137 138 lrm = DPXMULT(lxm, lym); 139 hrm = DPXMULT(hxm, hym); 140 141 t = DPXMULT(lxm, hym); 142 143 at = lrm + (t << 32); 144 hrm += at < lrm; 145 lrm = at; 146 147 hrm = hrm + (t >> 32); 148 149 t = DPXMULT(hxm, lym); 150 151 at = 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 * Sticky shift down to normal rounding precision. 161 */ 162 if ((s64) rm < 0) { 163 rm = (rm >> (64 - (DP_FBITS + 1 + 3))) | 164 ((rm << (DP_FBITS + 1 + 3)) != 0); 165 re++; 166 } else { 167 rm = (rm >> (64 - (DP_FBITS + 1 + 3 + 1))) | 168 ((rm << (DP_FBITS + 1 + 3 + 1)) != 0); 169 } 170 assert(rm & (DP_HIDDEN_BIT << 3)); 171 172 return ieee754dp_format(rs, re, rm); 173 } 174