libgcc/soft-fp/fixxfbitint.c

   1 /* Software floating-point emulation.
   2    Convert IEEE extended to signed or unsigned _BitInt.
   3
   4    Copyright (C) 2023 Free Software Foundation, Inc.
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 3, or (at your option) any later
  11 version.
  12
  13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16 for more details.
  17
  18 Under Section 7 of GPL version 3, you are granted additional
  19 permissions described in the GCC Runtime Library Exception, version
  20 3.1, as published by the Free Software Foundation.
  21
  22 You should have received a copy of the GNU General Public License and
  23 a copy of the GCC Runtime Library Exception along with this program;
  24 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  25 <http://www.gnu.org/licenses/>.  */
  26
  27 #include "soft-fp.h"
  28 #include "extended.h"
  29 #include "bitint.h"
  30
  31 #ifdef __BITINT_MAXWIDTH__
  32
  33 #ifndef TI_BITS
  34 /* While mantissa is 64 bits including 1 explicit bit, extended.h uses
  35    op-2.h for W_TYPE_SIZE 64 and op-4.h for W_TYPE_SIZE 32, so we have
  36    to use 128-bit type here.  On most 32-bit architectures TImode isn't
  37    supported, so use _BitInt(128) instead.  */
  38 typedef _BitInt(128) TItype;
  39 typedef unsigned _BitInt(128) UTItype;
  40 #define TI_BITS 128
  41 #endif
  42
  43 void
  44 __fixxfbitint (UBILtype *r, SItype rprec, XFtype a)
  45 {
  46   FP_DECL_EX;
  47   FP_DECL_E (A);
  48   USItype arprec = rprec < 0 ? -rprec : rprec;
  49   USItype rn = ((USItype) arprec + BIL_TYPE_SIZE - 1) / BIL_TYPE_SIZE;
  50   UTItype rv;
  51   USItype rsize = arprec > TI_BITS ? TI_BITS : arprec;
  52   USItype rsigned = rprec < 0;
  53   USItype ovf = 0;
  54   USItype shift = 0;
  55
  56   FP_INIT_EXCEPTIONS;
  57   FP_UNPACK_RAW_E (A, a);
  58   if (arprec > TI_BITS)
  59     {
  60       if (A_e < _FP_EXPBIAS_E || (A_s && !rsigned))
  61         ovf = 1;
  62       else if (A_e >= (_FP_EXPMAX_E < _FP_EXPBIAS_E + arprec
  63                        ? _FP_EXPMAX_E
  64                        : _FP_EXPBIAS_E + arprec - rsigned))
  65         {
  66           ovf = 1;
  67           if (A_s
  68               && A_e == _FP_EXPBIAS_E + arprec - 1
  69               && A_e < _FP_EXPMAX_E)
  70             A_e -= arprec - TI_BITS;
  71         }
  72       else if (A_e >= _FP_EXPBIAS_E + TI_BITS - rsigned)
  73         {
  74           shift = A_e - (_FP_EXPBIAS_E + TI_BITS - rsigned - 1);
  75           A_e -= shift;
  76         }
  77     }
  78   FP_TO_INT_E (rv, A, rsize, rsigned);
  79   FP_HANDLE_EXCEPTIONS;
  80   FP_TO_BITINT (r, rn, arprec, shift, rv, rsize, rsigned, ovf, TI);
  81 }
  82 #endif