arch/mips/math-emu/sp_tlong.c

   1 /* IEEE754 floating point arithmetic
   2  * single precision
   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 "ieee754sp.h"
  29
  30 s64 ieee754sp_tlong(ieee754sp x)
  31 {
  32         COMPXDP;                /* <-- need 64-bit mantissa tmp */
  33
  34         CLEARCX;
  35
  36         EXPLODEXSP;
  37         FLUSHXSP;
  38
  39         switch (xc) {
  40         case IEEE754_CLASS_SNAN:
  41         case IEEE754_CLASS_QNAN:
  42         case IEEE754_CLASS_INF:
  43                 SETCX(IEEE754_INVALID_OPERATION);
  44                 return ieee754di_xcpt(ieee754di_indef(), "sp_tlong", x);
  45         case IEEE754_CLASS_ZERO:
  46                 return 0;
  47         case IEEE754_CLASS_DNORM:
  48         case IEEE754_CLASS_NORM:
  49                 break;
  50         }
  51         if (xe >= 63) {
  52                 /* look for valid corner case */
  53                 if (xe == 63 && xs && xm == SP_HIDDEN_BIT)
  54                         return -0x8000000000000000LL;
  55                 /* Set invalid. We will only use overflow for floating
  56                    point overflow */
  57                 SETCX(IEEE754_INVALID_OPERATION);
  58                 return ieee754di_xcpt(ieee754di_indef(), "sp_tlong", x);
  59         }
  60         /* oh gawd */
  61         if (xe > SP_MBITS) {
  62                 xm <<= xe - SP_MBITS;
  63         } else if (xe < SP_MBITS) {
  64                 u32 residue;
  65                 int round;
  66                 int sticky;
  67                 int odd;
  68
  69                 if (xe < -1) {
  70                         residue = xm;
  71                         round = 0;
  72                         sticky = residue != 0;
  73                         xm = 0;
  74                 }
  75                 else {
  76                         residue = xm << (32 - SP_MBITS + xe);
  77                         round = (residue >> 31) != 0;
  78                         sticky = (residue << 1) != 0;
  79                         xm >>= SP_MBITS - xe;
  80                 }
  81                 odd = (xm & 0x1) != 0x0;
  82                 switch (ieee754_csr.rm) {
  83                 case IEEE754_RN:
  84                         if (round && (sticky || odd))
  85                                 xm++;
  86                         break;
  87                 case IEEE754_RZ:
  88                         break;
  89                 case IEEE754_RU:        /* toward +Infinity */
  90                         if ((round || sticky) && !xs)
  91                                 xm++;
  92                         break;
  93                 case IEEE754_RD:        /* toward -Infinity */
  94                         if ((round || sticky) && xs)
  95                                 xm++;
  96                         break;
  97                 }
  98                 if ((xm >> 63) != 0) {
  99                         /* This can happen after rounding */
 100                         SETCX(IEEE754_INVALID_OPERATION);
 101                         return ieee754di_xcpt(ieee754di_indef(), "sp_tlong", x);
 102                 }
 103                 if (round || sticky)
 104                         SETCX(IEEE754_INEXACT);
 105         }
 106         if (xs)
 107                 return -xm;
 108         else
 109                 return xm;
 110 }
 111
 112
 113 u64 ieee754sp_tulong(ieee754sp x)
 114 {
 115         ieee754sp hb = ieee754sp_1e63();
 116
 117         /* what if x < 0 ?? */
 118         if (ieee754sp_lt(x, hb))
 119                 return (u64) ieee754sp_tlong(x);
 120
 121         return (u64) ieee754sp_tlong(ieee754sp_sub(x, hb)) |
 122             (1ULL << 63);
 123 }