arch/mips/math-emu/sp_fmin.c

   1 /*
   2  * IEEE754 floating point arithmetic
   3  * single precision: MIN{,A}.f
   4  * MIN : Scalar Floating-Point Minimum
   5  * MINA: Scalar Floating-Point argument with Minimum Absolute Value
   6  *
   7  * MIN.S : FPR[fd] = minNum(FPR[fs],FPR[ft])
   8  * MINA.S: FPR[fd] = maxNumMag(FPR[fs],FPR[ft])
   9  *
  10  * MIPS floating point support
  11  * Copyright (C) 2015 Imagination Technologies, Ltd.
  12  * Author: Markos Chandras <markos.chandras@imgtec.com>
  13  *
  14  *  This program is free software; you can distribute it and/or modify it
  15  *  under the terms of the GNU General Public License as published by the
  16  *  Free Software Foundation; version 2 of the License.
  17  */
  18
  19 #include "ieee754sp.h"
  20
  21 union ieee754sp ieee754sp_fmin(union ieee754sp x, union ieee754sp y)
  22 {
  23         COMPXSP;
  24         COMPYSP;
  25
  26         EXPLODEXSP;
  27         EXPLODEYSP;
  28
  29         FLUSHXSP;
  30         FLUSHYSP;
  31
  32         ieee754_clearcx();
  33
  34         switch (CLPAIR(xc, yc)) {
  35         case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_SNAN):
  36         case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_SNAN):
  37         case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_SNAN):
  38         case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_SNAN):
  39         case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_SNAN):
  40                 return ieee754sp_nanxcpt(y);
  41
  42         case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_SNAN):
  43         case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_QNAN):
  44         case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_ZERO):
  45         case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_NORM):
  46         case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_DNORM):
  47         case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_INF):
  48                 return ieee754sp_nanxcpt(x);
  49
  50         /*
  51          * Quiet NaN handling
  52          */
  53
  54         /*
  55          *    The case of both inputs quiet NaNs
  56          */
  57         case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_QNAN):
  58                 return x;
  59
  60         /*
  61          *    The cases of exactly one input quiet NaN (numbers
  62          *    are here preferred as returned values to NaNs)
  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 x;
  69
  70         case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_ZERO):
  71         case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_NORM):
  72         case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_DNORM):
  73         case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_INF):
  74                 return y;
  75
  76         /*
  77          * Infinity and zero handling
  78          */
  79         case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO):
  80         case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM):
  81         case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM):
  82         case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO):
  83         case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO):
  84                 return xs ? x : y;
  85
  86         case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF):
  87         case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF):
  88         case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF):
  89         case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF):
  90         case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM):
  91         case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM):
  92                 return ys ? y : x;
  93
  94         case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
  95                 return ieee754sp_zero(xs | ys);
  96
  97         case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
  98                 SPDNORMX;
  99
 100         case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM):
 101                 SPDNORMY;
 102                 break;
 103
 104         case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM):
 105                 SPDNORMX;
 106         }
 107
 108         /* Finally get to do some computation */
 109
 110         assert(xm & SP_HIDDEN_BIT);
 111         assert(ym & SP_HIDDEN_BIT);
 112
 113         /* Compare signs */
 114         if (xs > ys)
 115                 return x;
 116         else if (xs < ys)
 117                 return y;
 118
 119         /* Signs of inputs are the same, let's compare exponents */
 120         if (xs == 0) {
 121                 /* Inputs are both positive */
 122                 if (xe > ye)
 123                         return y;
 124                 else if (xe < ye)
 125                         return x;
 126         } else {
 127                 /* Inputs are both negative */
 128                 if (xe > ye)
 129                         return x;
 130                 else if (xe < ye)
 131                         return y;
 132         }
 133
 134         /* Signs and exponents of inputs are equal, let's compare mantissas */
 135         if (xs == 0) {
 136                 /* Inputs are both positive, with equal signs and exponents */
 137                 if (xm <= ym)
 138                         return x;
 139                 return y;
 140         }
 141         /* Inputs are both negative, with equal signs and exponents */
 142         if (xm <= ym)
 143                 return y;
 144         return x;
 145 }
 146
 147 union ieee754sp ieee754sp_fmina(union ieee754sp x, union ieee754sp y)
 148 {
 149         COMPXSP;
 150         COMPYSP;
 151
 152         EXPLODEXSP;
 153         EXPLODEYSP;
 154
 155         FLUSHXSP;
 156         FLUSHYSP;
 157
 158         ieee754_clearcx();
 159
 160         switch (CLPAIR(xc, yc)) {
 161         case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_SNAN):
 162         case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_SNAN):
 163         case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_SNAN):
 164         case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_SNAN):
 165         case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_SNAN):
 166                 return ieee754sp_nanxcpt(y);
 167
 168         case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_SNAN):
 169         case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_QNAN):
 170         case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_ZERO):
 171         case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_NORM):
 172         case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_DNORM):
 173         case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_INF):
 174                 return ieee754sp_nanxcpt(x);
 175
 176         /*
 177          * Quiet NaN handling
 178          */
 179
 180         /*
 181          *    The case of both inputs quiet NaNs
 182          */
 183         case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_QNAN):
 184                 return x;
 185
 186         /*
 187          *    The cases of exactly one input quiet NaN (numbers
 188          *    are here preferred as returned values to NaNs)
 189          */
 190         case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_QNAN):
 191         case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_QNAN):
 192         case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_QNAN):
 193         case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_QNAN):
 194                 return x;
 195
 196         case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_ZERO):
 197         case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_NORM):
 198         case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_DNORM):
 199         case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_INF):
 200                 return y;
 201
 202         /*
 203          * Infinity and zero handling
 204          */
 205         case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF):
 206                 return ieee754sp_inf(xs | ys);
 207
 208         case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO):
 209         case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM):
 210         case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM):
 211         case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO):
 212         case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO):
 213                 return y;
 214
 215         case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF):
 216         case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF):
 217         case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF):
 218         case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM):
 219         case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM):
 220                 return x;
 221
 222         case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
 223                 return ieee754sp_zero(xs | ys);
 224
 225         case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
 226                 SPDNORMX;
 227
 228         case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM):
 229                 SPDNORMY;
 230                 break;
 231
 232         case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM):
 233                 SPDNORMX;
 234         }
 235
 236         /* Finally get to do some computation */
 237
 238         assert(xm & SP_HIDDEN_BIT);
 239         assert(ym & SP_HIDDEN_BIT);
 240
 241         /* Compare exponent */
 242         if (xe > ye)
 243                 return y;
 244         else if (xe < ye)
 245                 return x;
 246
 247         /* Compare mantissa */
 248         if (xm < ym)
 249                 return x;
 250         else if (xm > ym)
 251                 return y;
 252         else if (xs == 1)
 253                 return x;
 254         return y;
 255 }