denormal.c

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/*
 * Linux/PA-RISC Project (http://www.parisc-linux.org/)
 *
 * Floating-point emulation code
 *  Copyright (C) 2001 Hewlett-Packard (Paul Bame) <[email protected]>
 *
 *    This program is free software; you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License as published by
 *    the Free Software Foundation; either version 2, or (at your option)
 *    any later version.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program; if not, write to the Free Software
 *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
/*
 * BEGIN_DESC
 *
 *  File:
 *  @(#)    pa/fp/denormal.c        $ Revision: $
 *
 *  Purpose:
 *  <<please update with a synopsis of the functionality provided by this file>>
 *
 *  External Interfaces:
 *  <<the following list was autogenerated, please review>>
 *  dbl_denormalize(dbl_opndp1,dbl_opndp2,inexactflag,rmode)
 *  sgl_denormalize(sgl_opnd,inexactflag,rmode)
 *
 *  Internal Interfaces:
 *  <<please update>>
 *
 *  Theory:
 *  <<please update with a overview of the operation of this file>>
 *
 * END_DESC
*/



#include "float.h"
#include "sgl_float.h"
#include "dbl_float.h"
#include "hppa.h"
#include <linux/kernel.h>
/* #include <machine/sys/mdep_private.h> */

#undef Fpustatus_register
#define Fpustatus_register Fpu_register[0]

void
sgl_denormalize(unsigned int *sgl_opnd, boolean *inexactflag, int rmode)
{
    unsigned int opnd;
    int sign, exponent;
    boolean guardbit = FALSE, stickybit, inexact;

    opnd = *sgl_opnd;
    stickybit = *inexactflag;
        exponent = Sgl_exponent(opnd) - SGL_WRAP;
        sign = Sgl_sign(opnd);
    Sgl_denormalize(opnd,exponent,guardbit,stickybit,inexact);
    if (inexact) {
        switch (rmode) {
          case ROUNDPLUS:
        if (sign == 0) {
            Sgl_increment(opnd);
        }
        break;
          case ROUNDMINUS:
        if (sign != 0) {
            Sgl_increment(opnd);
        }
        break;
          case ROUNDNEAREST:
        if (guardbit && (stickybit || 
               Sgl_isone_lowmantissa(opnd))) {
               Sgl_increment(opnd);
        }
        break;
        }
    }
    Sgl_set_sign(opnd,sign);
    *sgl_opnd = opnd;
    *inexactflag = inexact;
    return;
}

void
dbl_denormalize(unsigned int *dbl_opndp1,
    unsigned int * dbl_opndp2,
    boolean *inexactflag,
    int rmode)
{
    unsigned int opndp1, opndp2;
    int sign, exponent;
    boolean guardbit = FALSE, stickybit, inexact;

    opndp1 = *dbl_opndp1;
    opndp2 = *dbl_opndp2;
    stickybit = *inexactflag;
    exponent = Dbl_exponent(opndp1) - DBL_WRAP;
    sign = Dbl_sign(opndp1);
    Dbl_denormalize(opndp1,opndp2,exponent,guardbit,stickybit,inexact);
    if (inexact) {
        switch (rmode) {
          case ROUNDPLUS:
        if (sign == 0) {
            Dbl_increment(opndp1,opndp2);
        }
        break;
          case ROUNDMINUS:
        if (sign != 0) {
            Dbl_increment(opndp1,opndp2);
        }
        break;
          case ROUNDNEAREST:
        if (guardbit && (stickybit || 
               Dbl_isone_lowmantissap2(opndp2))) {
               Dbl_increment(opndp1,opndp2);
        }
        break;
        }
    }
    Dbl_set_sign(opndp1,sign);
    *dbl_opndp1 = opndp1;
    *dbl_opndp2 = opndp2;
    *inexactflag = inexact;
    return;
}