gcc/libgcc/config/s390/32/_fixunssfdi.c

/* Definitions of target machine for GNU compiler, for IBM S/390
   Copyright (C) 1999-2013 Free Software Foundation, Inc.
   Contributed by Hartmut Penner (hpenner@de.ibm.com) and
                  Ulrich Weigand (uweigand@de.ibm.com).

This file is part of GCC.

GCC 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 3, or (at your option) any later
version.

GCC 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.

Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.

You should have received a copy of the GNU General Public License and
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
<http://www.gnu.org/licenses/>.  */

#define EXP(fp)         (((fp.l) >> 23) & 0xFF)
#define EXCESS          126
#define SIGNBIT         0x80000000
#define SIGN(fp)        ((fp.l) & SIGNBIT)
#define HIDDEN          (1 << 23)
#define MANT(fp)        (((fp.l) & 0x7FFFFF) | HIDDEN)
#define FRAC(fp)        ((fp.l) & 0x7FFFFF)

typedef int DItype_x __attribute__ ((mode (DI)));
typedef unsigned int UDItype_x __attribute__ ((mode (DI)));
typedef int SItype_x __attribute__ ((mode (SI)));
typedef unsigned int USItype_x __attribute__ ((mode (SI)));

union float_long
  {
    float f;
    USItype_x l;
  };

UDItype_x __fixunssfdi (float a1);

/* convert float to unsigned int */
UDItype_x
__fixunssfdi (float a1)
{
    register union float_long fl1;
    register int exp;
    register UDItype_x l;

    fl1.f = a1;

    /* +/- 0, denormalized, negative */

    if (!EXP (fl1) || SIGN(fl1))
      return 0;

    exp = EXP (fl1) - EXCESS - 24;

    /* number < 1 */

    if (exp < -24)
      return 0;

    /* NaN */

    if ((EXP(fl1) == 0xff) && (FRAC(fl1) != 0)) /* NaN */
      return 0x0ULL;

    /* Number big number & + inf */

    if (exp >= 41) {
      return 0xFFFFFFFFFFFFFFFFULL;
    }

    l = MANT(fl1);

    if (exp > 0)
      l <<= exp;
    else
      l >>= -exp;

    return l;
}