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      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
     83