arch/mips/math-emu/dp_fmax.c

   1 /*
   2  * IEEE754 floating point arithmetic
   3  * double precision: MIN{,A}.f
   4  * MIN : Scalar Floating-Point Minimum
   5  * MINA: Scalar Floating-Point argument with Minimum Absolute Value
   6  *
   7  * MIN.D : FPR[fd] = minNum(FPR[fs],FPR[ft])
   8  * MINA.D: 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 "ieee754dp.h"
  20
  21 union ieee754dp ieee754dp_fmax(union ieee754dp x, union ieee754dp y)
  22 {
  23         COMPXDP;
  24         COMPYDP;
  25
  26         EXPLODEXDP;
  27         EXPLODEYDP;
  28
  29         FLUSHXDP;
  30         FLUSHYDP;
  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 ieee754dp_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 ieee754dp_nanxcpt(x);
  49
  50         /* numbers are preferred to NaNs */
  51         case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_QNAN):
  52         case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_QNAN):
  53         case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_QNAN):
  54         case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_QNAN):
  55                 return x;
  56
  57         case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_QNAN):
  58         case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_ZERO):
  59         case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_NORM):
  60         case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_DNORM):
  61         case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_INF):
  62                 return y;
  63
  64         /*
  65          * Infinity and zero handling
  66          */
  67         case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO):
  68         case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM):
  69         case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM):
  70         case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO):
  71         case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO):
  72                 return xs ? y : x;
  73
  74         case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF):
  75         case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF):
  76         case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF):
  77         case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF):
  78         case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM):
  79         case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM):
  80                 return ys ? x : y;
  81
  82         case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
  83                 if (xs == ys)
  84                         return x;
  85                 return ieee754dp_zero(1);
  86
  87         case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
  88                 DPDNORMX;
  89
  90         case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM):
  91                 DPDNORMY;
  92                 break;
  93
  94         case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM):
  95                 DPDNORMX;
  96         }
  97
  98         /* Finally get to do some computation */
  99
 100         assert(xm & DP_HIDDEN_BIT);
 101         assert(ym & DP_HIDDEN_BIT);
 102
 103         /* Compare signs */
 104         if (xs > ys)
 105                 return y;
 106         else if (xs < ys)
 107                 return x;
 108
 109         /* Compare exponent */
 110         if (xe > ye)
 111                 return x;
 112         else if (xe < ye)
 113                 return y;
 114
 115         /* Compare mantissa */
 116         if (xm <= ym)
 117                 return y;
 118         return x;
 119 }
 120
 121 union ieee754dp ieee754dp_fmaxa(union ieee754dp x, union ieee754dp y)
 122 {
 123         COMPXDP;
 124         COMPYDP;
 125
 126         EXPLODEXDP;
 127         EXPLODEYDP;
 128
 129         FLUSHXDP;
 130         FLUSHYDP;
 131
 132         ieee754_clearcx();
 133
 134         switch (CLPAIR(xc, yc)) {
 135         case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_SNAN):
 136         case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_SNAN):
 137         case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_SNAN):
 138         case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_SNAN):
 139         case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_SNAN):
 140                 return ieee754dp_nanxcpt(y);
 141
 142         case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_SNAN):
 143         case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_QNAN):
 144         case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_ZERO):
 145         case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_NORM):
 146         case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_DNORM):
 147         case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_INF):
 148                 return ieee754dp_nanxcpt(x);
 149
 150         /* numbers are preferred to NaNs */
 151         case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_QNAN):
 152         case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_QNAN):
 153         case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_QNAN):
 154         case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_QNAN):
 155                 return x;
 156
 157         case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_QNAN):
 158         case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_ZERO):
 159         case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_NORM):
 160         case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_DNORM):
 161         case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_INF):
 162                 return y;
 163
 164         /*
 165          * Infinity and zero handling
 166          */
 167         case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO):
 168         case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM):
 169         case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM):
 170         case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO):
 171         case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO):
 172                 return x;
 173
 174         case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF):
 175         case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF):
 176         case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF):
 177         case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF):
 178         case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM):
 179         case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM):
 180                 return y;
 181
 182         case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
 183                 if (xs == ys)
 184                         return x;
 185                 return ieee754dp_zero(1);
 186
 187         case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
 188                 DPDNORMX;
 189
 190         case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM):
 191                 DPDNORMY;
 192                 break;
 193
 194         case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM):
 195                 DPDNORMX;
 196         }
 197
 198         /* Finally get to do some computation */
 199
 200         assert(xm & DP_HIDDEN_BIT);
 201         assert(ym & DP_HIDDEN_BIT);
 202
 203         /* Compare exponent */
 204         if (xe > ye)
 205                 return x;
 206         else if (xe < ye)
 207                 return y;
 208
 209         /* Compare mantissa */
 210         if (xm <= ym)
 211                 return y;
 212         return x;
 213 }