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fcnvfx.c

/*
 * Linux/PA-RISC Project (http://www.parisc-linux.org/)
 *
 * Floating-point emulation code
 *  Copyright (C) 2001 Hewlett-Packard (Paul Bame) <bame@debian.org>
 *
 *    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/spmath/fcnvfx.c            $Revision: 1.1 $
 *
 *  Purpose:
 *    Single Floating-point to Single Fixed-point
 *    Single Floating-point to Double Fixed-point 
 *    Double Floating-point to Single Fixed-point 
 *    Double Floating-point to Double Fixed-point 
 *
 *  External Interfaces:
 *    dbl_to_dbl_fcnvfx(srcptr,nullptr,dstptr,status)
 *    dbl_to_sgl_fcnvfx(srcptr,nullptr,dstptr,status)
 *    sgl_to_dbl_fcnvfx(srcptr,nullptr,dstptr,status)
 *    sgl_to_sgl_fcnvfx(srcptr,nullptr,dstptr,status)
 *
 *  Internal Interfaces:
 *
 *  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 "cnv_float.h"

/*
 *  Single Floating-point to Single Fixed-point 
 */
/*ARGSUSED*/
int
sgl_to_sgl_fcnvfx(
                sgl_floating_point *srcptr,
                sgl_floating_point *nullptr,
                int *dstptr,
                sgl_floating_point *status)
{
      register unsigned int src, temp;
      register int src_exponent, result;
      register boolean inexact = FALSE;

      src = *srcptr;
      src_exponent = Sgl_exponent(src) - SGL_BIAS;

      /* 
       * Test for overflow
       */
      if (src_exponent > SGL_FX_MAX_EXP) {
            /* check for MININT */
            if ((src_exponent > SGL_FX_MAX_EXP + 1) || 
            Sgl_isnotzero_mantissa(src) || Sgl_iszero_sign(src)) {
                        if (Sgl_iszero_sign(src)) result = 0x7fffffff;
                        else result = 0x80000000; 

                      if (Is_invalidtrap_enabled()) {
                            return(INVALIDEXCEPTION);
                        }
                        Set_invalidflag();
                  *dstptr = result;
                  return(NOEXCEPTION);
                  }
      }
      /*
       * Generate result
       */
      if (src_exponent >= 0) {
            temp = src;
            Sgl_clear_signexponent_set_hidden(temp);
            Int_from_sgl_mantissa(temp,src_exponent);
            if (Sgl_isone_sign(src))  result = -Sgl_all(temp);
            else result = Sgl_all(temp);

            /* check for inexact */
            if (Sgl_isinexact_to_fix(src,src_exponent)) {
                  inexact = TRUE;
                  /*  round result  */
                  switch (Rounding_mode()) {
                  case ROUNDPLUS:
                       if (Sgl_iszero_sign(src)) result++;
                       break;
                  case ROUNDMINUS:
                       if (Sgl_isone_sign(src)) result--;
                       break;
                  case ROUNDNEAREST:
                       if (Sgl_isone_roundbit(src,src_exponent)) {
                          if (Sgl_isone_stickybit(src,src_exponent) 
                        || (Sgl_isone_lowmantissa(temp)))
                             if (Sgl_iszero_sign(src)) result++;
                             else result--;
                       }
                  } 
            }
      }
      else {
            result = 0;

            /* check for inexact */
            if (Sgl_isnotzero_exponentmantissa(src)) {
                  inexact = TRUE;
                  /*  round result  */
                  switch (Rounding_mode()) {
                  case ROUNDPLUS:
                       if (Sgl_iszero_sign(src)) result++;
                       break;
                  case ROUNDMINUS:
                       if (Sgl_isone_sign(src)) result--;
                       break;
                  case ROUNDNEAREST:
                       if (src_exponent == -1)
                          if (Sgl_isnotzero_mantissa(src))
                             if (Sgl_iszero_sign(src)) result++;
                             else result--;
                  } 
            }
      }
      *dstptr = result;
      if (inexact) {
            if (Is_inexacttrap_enabled()) return(INEXACTEXCEPTION);
            else Set_inexactflag();
      }
      return(NOEXCEPTION);
}

/*
 *  Single Floating-point to Double Fixed-point 
 */
/*ARGSUSED*/
int
sgl_to_dbl_fcnvfx(
            sgl_floating_point *srcptr,
            unsigned int *nullptr,
            dbl_integer *dstptr,
            unsigned int *status)
{
      register int src_exponent, resultp1;
      register unsigned int src, temp, resultp2;
      register boolean inexact = FALSE;

      src = *srcptr;
      src_exponent = Sgl_exponent(src) - SGL_BIAS;

      /* 
       * Test for overflow
       */
      if (src_exponent > DBL_FX_MAX_EXP) {
            /* check for MININT */
            if ((src_exponent > DBL_FX_MAX_EXP + 1) || 
            Sgl_isnotzero_mantissa(src) || Sgl_iszero_sign(src)) {
                        if (Sgl_iszero_sign(src)) {
                              resultp1 = 0x7fffffff;
                        resultp2 = 0xffffffff;
                  }
                        else {
                      resultp1 = 0x80000000; 
                      resultp2 = 0;
                  }
                      if (Is_invalidtrap_enabled()) {
                            return(INVALIDEXCEPTION);
                        }
                        Set_invalidflag();
                    Dint_copytoptr(resultp1,resultp2,dstptr);
                  return(NOEXCEPTION);
            }
            Dint_set_minint(resultp1,resultp2);
            Dint_copytoptr(resultp1,resultp2,dstptr);
            return(NOEXCEPTION);
      }
      /*
       * Generate result
       */
      if (src_exponent >= 0) {
            temp = src;
            Sgl_clear_signexponent_set_hidden(temp);
            Dint_from_sgl_mantissa(temp,src_exponent,resultp1,resultp2);
            if (Sgl_isone_sign(src)) {
                  Dint_setone_sign(resultp1,resultp2);
            }

            /* check for inexact */
            if (Sgl_isinexact_to_fix(src,src_exponent)) {
                  inexact = TRUE;
                        /*  round result  */
                        switch (Rounding_mode()) {
                        case ROUNDPLUS:
                             if (Sgl_iszero_sign(src)) {
                        Dint_increment(resultp1,resultp2);
                       }
                             break;
                        case ROUNDMINUS:
                             if (Sgl_isone_sign(src)) {
                        Dint_decrement(resultp1,resultp2);
                       }
                             break;
                        case ROUNDNEAREST:
                             if (Sgl_isone_roundbit(src,src_exponent))
                                if (Sgl_isone_stickybit(src,src_exponent) || 
                        (Dint_isone_lowp2(resultp2)))
                           if (Sgl_iszero_sign(src)) {
                              Dint_increment(resultp1,resultp2);
                           }
                                   else {
                              Dint_decrement(resultp1,resultp2);
                           }
                        }
                }
        }
      else {
            Dint_setzero(resultp1,resultp2);

            /* check for inexact */
            if (Sgl_isnotzero_exponentmantissa(src)) {
                  inexact = TRUE;
                        /*  round result  */
                        switch (Rounding_mode()) {
                        case ROUNDPLUS:
                             if (Sgl_iszero_sign(src)) {
                        Dint_increment(resultp1,resultp2);
                       }
                             break;
                        case ROUNDMINUS:
                             if (Sgl_isone_sign(src)) {
                        Dint_decrement(resultp1,resultp2);
                       }
                             break;
                        case ROUNDNEAREST:
                             if (src_exponent == -1)
                                if (Sgl_isnotzero_mantissa(src))
                                   if (Sgl_iszero_sign(src)) {
                              Dint_increment(resultp1,resultp2);
                           }
                                   else {
                              Dint_decrement(resultp1,resultp2);
                           }
                  }
            }
      }
      Dint_copytoptr(resultp1,resultp2,dstptr);
      if (inexact) {
            if (Is_inexacttrap_enabled()) return(INEXACTEXCEPTION);
            else Set_inexactflag();
      }
      return(NOEXCEPTION);
}

/*
 *  Double Floating-point to Single Fixed-point 
 */
/*ARGSUSED*/
int
dbl_to_sgl_fcnvfx(
                dbl_floating_point *srcptr,
                unsigned int *nullptr,
                int *dstptr,
                unsigned int *status)
{
      register unsigned int srcp1,srcp2, tempp1,tempp2;
      register int src_exponent, result;
      register boolean inexact = FALSE;

      Dbl_copyfromptr(srcptr,srcp1,srcp2);
      src_exponent = Dbl_exponent(srcp1) - DBL_BIAS;

      /* 
       * Test for overflow
       */
      if (src_exponent > SGL_FX_MAX_EXP) {
            /* check for MININT */
            if (Dbl_isoverflow_to_int(src_exponent,srcp1,srcp2)) {
                        if (Dbl_iszero_sign(srcp1)) result = 0x7fffffff;
                        else result = 0x80000000; 

                      if (Is_invalidtrap_enabled()) {
                            return(INVALIDEXCEPTION);
                        }
                        Set_invalidflag();
                  *dstptr = result;
                  return(NOEXCEPTION);
            }
      }
      /*
       * Generate result
       */
      if (src_exponent >= 0) {
            tempp1 = srcp1;
            tempp2 = srcp2;
            Dbl_clear_signexponent_set_hidden(tempp1);
            Int_from_dbl_mantissa(tempp1,tempp2,src_exponent);
            if (Dbl_isone_sign(srcp1) && (src_exponent <= SGL_FX_MAX_EXP))
                  result = -Dbl_allp1(tempp1);
            else result = Dbl_allp1(tempp1);

            /* check for inexact */
            if (Dbl_isinexact_to_fix(srcp1,srcp2,src_exponent)) {
                        inexact = TRUE;
                        /*  round result  */
                        switch (Rounding_mode()) {
                        case ROUNDPLUS:
                             if (Dbl_iszero_sign(srcp1)) result++;
                             break;
                        case ROUNDMINUS:
                             if (Dbl_isone_sign(srcp1)) result--;
                             break;
                        case ROUNDNEAREST:
                             if (Dbl_isone_roundbit(srcp1,srcp2,src_exponent))
                                if (Dbl_isone_stickybit(srcp1,srcp2,src_exponent) || 
                        (Dbl_isone_lowmantissap1(tempp1)))
                                   if (Dbl_iszero_sign(srcp1)) result++;
                                   else result--;
                        } 
                  /* check for overflow */
                  if ((Dbl_iszero_sign(srcp1) && result < 0) ||
                      (Dbl_isone_sign(srcp1) && result > 0)) {
                          
                          if (Dbl_iszero_sign(srcp1)) result = 0x7fffffff;
                          else result = 0x80000000; 

                        if (Is_invalidtrap_enabled()) {
                            return(INVALIDEXCEPTION);
                          }
                          Set_invalidflag();
                    *dstptr = result;
                    return(NOEXCEPTION);
                  }
                }
      }
      else {
            result = 0;

            /* check for inexact */
            if (Dbl_isnotzero_exponentmantissa(srcp1,srcp2)) {
                        inexact = TRUE;
                        /*  round result  */
                        switch (Rounding_mode()) {
                        case ROUNDPLUS:
                             if (Dbl_iszero_sign(srcp1)) result++;
                             break;
                        case ROUNDMINUS:
                             if (Dbl_isone_sign(srcp1)) result--;
                             break;
                        case ROUNDNEAREST:
                             if (src_exponent == -1)
                                if (Dbl_isnotzero_mantissa(srcp1,srcp2))
                                   if (Dbl_iszero_sign(srcp1)) result++;
                                   else result--;
                  }
                }
      }
      *dstptr = result;
        if (inexact) {
                if (Is_inexacttrap_enabled()) return(INEXACTEXCEPTION);
            else Set_inexactflag();
        }
      return(NOEXCEPTION);
}

/*
 *  Double Floating-point to Double Fixed-point 
 */
/*ARGSUSED*/
int
dbl_to_dbl_fcnvfx(
                dbl_floating_point *srcptr,
                unsigned int *nullptr,
                dbl_integer *dstptr,
                unsigned int *status)
{
      register int src_exponent, resultp1;
      register unsigned int srcp1, srcp2, tempp1, tempp2, resultp2;
      register boolean inexact = FALSE;

      Dbl_copyfromptr(srcptr,srcp1,srcp2);
      src_exponent = Dbl_exponent(srcp1) - DBL_BIAS;

      /* 
       * Test for overflow
       */
      if (src_exponent > DBL_FX_MAX_EXP) {
            /* check for MININT */
            if ((src_exponent > DBL_FX_MAX_EXP + 1) || 
            Dbl_isnotzero_mantissa(srcp1,srcp2) || Dbl_iszero_sign(srcp1)) {
                        if (Dbl_iszero_sign(srcp1)) {
                              resultp1 = 0x7fffffff;
                        resultp2 = 0xffffffff;
                  }
                        else {
                      resultp1 = 0x80000000; 
                      resultp2 = 0;
                  }
                      if (Is_invalidtrap_enabled()) {
                            return(INVALIDEXCEPTION);
                        }
                        Set_invalidflag();
                    Dint_copytoptr(resultp1,resultp2,dstptr);
                  return(NOEXCEPTION);
            }
      }
 
      /*
       * Generate result
       */
      if (src_exponent >= 0) {
            tempp1 = srcp1;
            tempp2 = srcp2;
            Dbl_clear_signexponent_set_hidden(tempp1);
            Dint_from_dbl_mantissa(tempp1,tempp2,src_exponent,resultp1,
            resultp2);
            if (Dbl_isone_sign(srcp1)) {
                  Dint_setone_sign(resultp1,resultp2);
            }

            /* check for inexact */
            if (Dbl_isinexact_to_fix(srcp1,srcp2,src_exponent)) {
                        inexact = TRUE;
                        /*  round result  */
                        switch (Rounding_mode()) {
                        case ROUNDPLUS:
                             if (Dbl_iszero_sign(srcp1)) {
                        Dint_increment(resultp1,resultp2);
                       }
                             break;
                        case ROUNDMINUS:
                             if (Dbl_isone_sign(srcp1)) {
                        Dint_decrement(resultp1,resultp2);
                       }
                             break;
                        case ROUNDNEAREST:
                             if (Dbl_isone_roundbit(srcp1,srcp2,src_exponent))
                                if (Dbl_isone_stickybit(srcp1,srcp2,src_exponent) || 
                        (Dint_isone_lowp2(resultp2)))
                                   if (Dbl_iszero_sign(srcp1)) {
                              Dint_increment(resultp1,resultp2);
                           }
                                   else {
                              Dint_decrement(resultp1,resultp2);
                           }
                        } 
                }
      }
      else {
            Dint_setzero(resultp1,resultp2);

            /* check for inexact */
            if (Dbl_isnotzero_exponentmantissa(srcp1,srcp2)) {
                        inexact = TRUE;
                        /*  round result  */
                        switch (Rounding_mode()) {
                        case ROUNDPLUS:
                             if (Dbl_iszero_sign(srcp1)) {
                        Dint_increment(resultp1,resultp2);
                       }
                             break;
                        case ROUNDMINUS:
                             if (Dbl_isone_sign(srcp1)) {
                        Dint_decrement(resultp1,resultp2);
                       }
                             break;
                        case ROUNDNEAREST:
                             if (src_exponent == -1)
                                if (Dbl_isnotzero_mantissa(srcp1,srcp2))
                                   if (Dbl_iszero_sign(srcp1)) {
                              Dint_increment(resultp1,resultp2);
                           }
                                   else {
                              Dint_decrement(resultp1,resultp2);
                           }
                  }
                }
      }
      Dint_copytoptr(resultp1,resultp2,dstptr);
        if (inexact) {
                if (Is_inexacttrap_enabled()) return(INEXACTEXCEPTION);
            else Set_inexactflag();
        }
      return(NOEXCEPTION);
}

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