gcc/ada/cuintp.c

   1 /****************************************************************************
   2  *                                                                          *
   3  *                        GNAT COMPILER COMPONENTS                          *
   4  *                                                                          *
   5  *                               C U I N T P                                *
   6  *                                                                          *
   7  *                          C Implementation File                           *
   8  *                                                                          *
   9  *                            $Revision: 1.1 $
  10  *                                                                          *
  11  *          Copyright (C) 1992-2001 Free Software Foundation, Inc.          *
  12  *                                                                          *
  13  * GNAT is free software;  you can  redistribute it  and/or modify it under *
  14  * terms of the  GNU General Public License as published  by the Free Soft- *
  15  * ware  Foundation;  either version 2,  or (at your option) any later ver- *
  16  * sion.  GNAT is distributed in the hope that it will be useful, but WITH- *
  17  * OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY *
  18  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License *
  19  * for  more details.  You should have  received  a copy of the GNU General *
  20  * Public License  distributed with GNAT;  see file COPYING.  If not, write *
  21  * to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, *
  22  * MA 02111-1307, USA.                                                      *
  23  *                                                                          *
  24  * GNAT was originally developed  by the GNAT team at  New York University. *
  25  * Extensive contributions were provided by Ada Core Technologies Inc.      *
  26  *                                                                          *
  27  ****************************************************************************/
  28
  29 /* This file corresponds to the Ada package body Uintp. It was created
  30    manually from the files uintp.ads and uintp.adb. */
  31
  32 #include "config.h"
  33 #include "system.h"
  34 #include "tree.h"
  35 #include "ada.h"
  36 #include "types.h"
  37 #include "uintp.h"
  38 #include "atree.h"
  39 #include "elists.h"
  40 #include "nlists.h"
  41 #include "stringt.h"
  42 #include "fe.h"
  43 #include "gigi.h"
  44
  45 /* Universal integers are represented by the Uint type which is an index into
  46    the Uints_Ptr table containing Uint_Entry values.  A Uint_Entry contains an
  47    index and length for getting the "digits" of the universal integer from the
  48    Udigits_Ptr table.
  49
  50    For efficiency, this method is used only for integer values larger than the
  51    constant Uint_Bias.  If a Uint is less than this constant, then it contains
  52    the integer value itself.  The origin of the Uints_Ptr table is adjusted so
  53    that a Uint value of Uint_Bias indexes the first element.  */
  54
  55 /* Similarly to UI_To_Int, but return a GCC INTEGER_CST.  Overflow is tested
  56    by the constant-folding used to build the node.  TYPE is the GCC type of the
  57    resulting node.  */
  58
  59 tree
  60 UI_To_gnu (Input, type)
  61      Uint Input;
  62      tree type;
  63 {
  64   tree gnu_ret;
  65
  66   if (Input <= Uint_Direct_Last)
  67     gnu_ret = convert (type, build_int_2 (Input - Uint_Direct_Bias,
  68                                           Input < Uint_Direct_Bias ? -1 : 0));
  69   else
  70     {
  71       Int Idx =    Uints_Ptr[Input].Loc;
  72       Pos Length = Uints_Ptr[Input].Length;
  73       Int First = Udigits_Ptr[Idx];
  74       /* Do computations in integer type or TYPE whichever is wider, then
  75          convert later.  This avoid overflow if type is short integer.  */
  76       tree comp_type
  77         = (TYPE_PRECISION (type) >= TYPE_PRECISION (integer_type_node)
  78            ? type : integer_type_node);
  79       tree gnu_base = convert (comp_type, build_int_2 (Base, 0));
  80
  81       if (Length <= 0)
  82         gigi_abort (601);
  83
  84       gnu_ret = convert (comp_type, build_int_2 (First, First < 0 ? -1 : 0));
  85       if (First < 0)
  86         for (Idx++, Length--; Length; Idx++, Length--)
  87           gnu_ret = fold (build (MINUS_EXPR, comp_type,
  88                                  fold (build (MULT_EXPR, comp_type,
  89                                               gnu_ret, gnu_base)),
  90                                  convert (comp_type,
  91                                           build_int_2 (Udigits_Ptr[Idx], 0))));
  92       else
  93         for (Idx++, Length--; Length; Idx++, Length--)
  94           gnu_ret = fold (build (PLUS_EXPR, comp_type,
  95                                  fold (build (MULT_EXPR, comp_type,
  96                                               gnu_ret, gnu_base)),
  97                                  convert (comp_type,
  98                                           build_int_2 (Udigits_Ptr[Idx], 0))));
  99     }
 100
 101   gnu_ret = convert (type, gnu_ret);
 102
 103   /* We don't need any NOP_EXPR or NON_LVALUE_EXPR on GNU_RET.  */
 104   while ((TREE_CODE (gnu_ret) == NOP_EXPR
 105           || TREE_CODE (gnu_ret) == NON_LVALUE_EXPR)
 106          && TREE_TYPE (TREE_OPERAND (gnu_ret, 0)) == TREE_TYPE (gnu_ret))
 107     gnu_ret = TREE_OPERAND (gnu_ret, 0);
 108
 109   return gnu_ret;
 110 }