arch/parisc/math-emu/denormal.c

   1 /*
   2  * Linux/PA-RISC Project (http://www.parisc-linux.org/)
   3  *
   4  * Floating-point emulation code
   5  *  Copyright (C) 2001 Hewlett-Packard (Paul Bame) <bame@debian.org>
   6  *
   7  *    This program is free software; you can redistribute it and/or modify
   8  *    it under the terms of the GNU General Public License as published by
   9  *    the Free Software Foundation; either version 2, or (at your option)
  10  *    any later version.
  11  *
  12  *    This program is distributed in the hope that it will be useful,
  13  *    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  *    GNU General Public License for more details.
  16  *
  17  *    You should have received a copy of the GNU General Public License
  18  *    along with this program; if not, write to the Free Software
  19  *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  */
  21 /*
  22  * BEGIN_DESC
  23  *
  24  *  File:
  25  *      @(#)    pa/fp/denormal.c                $ Revision: $
  26  *
  27  *  Purpose:
  28  *      <<please update with a synopsis of the functionality provided by this file>>
  29  *
  30  *  External Interfaces:
  31  *      <<the following list was autogenerated, please review>>
  32  *      dbl_denormalize(dbl_opndp1,dbl_opndp2,inexactflag,rmode)
  33  *      sgl_denormalize(sgl_opnd,inexactflag,rmode)
  34  *
  35  *  Internal Interfaces:
  36  *      <<please update>>
  37  *
  38  *  Theory:
  39  *      <<please update with a overview of the operation of this file>>
  40  *
  41  * END_DESC
  42 */
  43
  44
  45
  46 #include "float.h"
  47 #include "sgl_float.h"
  48 #include "dbl_float.h"
  49 #include "hppa.h"
  50 #include <linux/kernel.h>
  51 /* #include <machine/sys/mdep_private.h> */
  52
  53 #undef Fpustatus_register
  54 #define Fpustatus_register Fpu_register[0]
  55
  56 void
  57 sgl_denormalize(unsigned int *sgl_opnd, boolean *inexactflag, int rmode)
  58 {
  59         unsigned int opnd;
  60         int sign, exponent;
  61         boolean guardbit = FALSE, stickybit, inexact;
  62
  63         opnd = *sgl_opnd;
  64         stickybit = *inexactflag;
  65         exponent = Sgl_exponent(opnd) - SGL_WRAP;
  66         sign = Sgl_sign(opnd);
  67         Sgl_denormalize(opnd,exponent,guardbit,stickybit,inexact);
  68         if (inexact) {
  69             switch (rmode) {
  70               case ROUNDPLUS:
  71                 if (sign == 0) {
  72                         Sgl_increment(opnd);
  73                 }
  74                 break;
  75               case ROUNDMINUS:
  76                 if (sign != 0) {
  77                         Sgl_increment(opnd);
  78                 }
  79                 break;
  80               case ROUNDNEAREST:
  81                 if (guardbit && (stickybit ||
  82                        Sgl_isone_lowmantissa(opnd))) {
  83                            Sgl_increment(opnd);
  84                 }
  85                 break;
  86             }
  87         }
  88         Sgl_set_sign(opnd,sign);
  89         *sgl_opnd = opnd;
  90         *inexactflag = inexact;
  91         return;
  92 }
  93
  94 void
  95 dbl_denormalize(unsigned int *dbl_opndp1,
  96         unsigned int * dbl_opndp2,
  97         boolean *inexactflag,
  98         int rmode)
  99 {
 100         unsigned int opndp1, opndp2;
 101         int sign, exponent;
 102         boolean guardbit = FALSE, stickybit, inexact;
 103
 104         opndp1 = *dbl_opndp1;
 105         opndp2 = *dbl_opndp2;
 106         stickybit = *inexactflag;
 107         exponent = Dbl_exponent(opndp1) - DBL_WRAP;
 108         sign = Dbl_sign(opndp1);
 109         Dbl_denormalize(opndp1,opndp2,exponent,guardbit,stickybit,inexact);
 110         if (inexact) {
 111             switch (rmode) {
 112               case ROUNDPLUS:
 113                 if (sign == 0) {
 114                         Dbl_increment(opndp1,opndp2);
 115                 }
 116                 break;
 117               case ROUNDMINUS:
 118                 if (sign != 0) {
 119                         Dbl_increment(opndp1,opndp2);
 120                 }
 121                 break;
 122               case ROUNDNEAREST:
 123                 if (guardbit && (stickybit ||
 124                        Dbl_isone_lowmantissap2(opndp2))) {
 125                            Dbl_increment(opndp1,opndp2);
 126                 }
 127                 break;
 128             }
 129         }
 130         Dbl_set_sign(opndp1,sign);
 131         *dbl_opndp1 = opndp1;
 132         *dbl_opndp2 = opndp2;
 133         *inexactflag = inexact;
 134         return;
 135 }