gcc/ada/eval_fat.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                             E V A L _ F A T                              --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2004 Free Software Foundation, Inc.          --
  10 --                                                                          --
  11 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  12 -- terms of the  GNU General Public License as published  by the Free Soft- --
  13 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  14 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  15 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  16 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  17 -- for  more details.  You should have  received  a copy of the GNU General --
  18 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  19 -- to  the  Free Software Foundation,  51  Franklin  Street,  Fifth  Floor, --
  20 -- Boston, MA 02110-1301, USA.                                              --
  21 --                                                                          --
  22 -- GNAT was originally developed  by the GNAT team at  New York University. --
  23 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  24 --                                                                          --
  25 ------------------------------------------------------------------------------
  26
  27 --  This package provides for compile-time evaluation of static calls to the
  28 --  floating-point attribute functions. It is the compile-time equivalent of
  29 --  the System.Fat_Gen runtime package. The coding is quite similar, as are
  30 --  the subprogram specs, except that the type is passed as an explicit
  31 --  first parameter (and used via ttypes, to obtain the necessary information
  32 --  about the characteristics of the type for computing the results.
  33
  34 with Types;  use Types;
  35 with Uintp;  use Uintp;
  36 with Urealp; use Urealp;
  37
  38 package Eval_Fat is
  39
  40    subtype UI is Uint;
  41    --  The compile time representation of universal integer
  42
  43    subtype T is Ureal;
  44    --  The compile time representation of floating-point values
  45
  46    subtype R is Entity_Id;
  47    --  The compile time representation of the floating-point root type
  48
  49    --  The following functions perform the operation implied by their name
  50    --  which corresponds to the name of the attribute which they compute.
  51    --  The arguments correspond to the attribute function arguments.
  52
  53    function Adjacent          (RT : R; X, Towards : T)              return T;
  54
  55    function Ceiling           (RT : R; X : T)                       return T;
  56
  57    function Compose           (RT : R; Fraction : T; Exponent : UI) return T;
  58
  59    function Copy_Sign         (RT : R; Value, Sign : T)             return T;
  60
  61    function Exponent          (RT : R; X : T)                       return UI;
  62
  63    function Floor             (RT : R; X : T)                       return T;
  64
  65    function Fraction          (RT : R; X : T)                       return T;
  66
  67    function Leading_Part      (RT : R; X : T; Radix_Digits : UI)    return T;
  68
  69    function Machine_Mantissa  (RT : R)                              return Nat;
  70
  71    function Machine_Radix     (RT : R)                              return Nat;
  72
  73    function Model             (RT : R; X : T)                       return T;
  74
  75    function Pred              (RT : R; X : T)                       return T;
  76
  77    function Remainder         (RT : R; X, Y : T)                    return T;
  78
  79    function Rounding          (RT : R; X : T)                       return T;
  80
  81    function Scaling           (RT : R; X : T; Adjustment : UI)      return T;
  82
  83    function Succ              (RT : R; X : T)                       return T;
  84
  85    function Truncation        (RT : R; X : T)                       return T;
  86
  87    function Unbiased_Rounding (RT : R; X : T)                       return T;
  88
  89    --  The following global declarations are used by the Machine attribute
  90
  91    type Rounding_Mode is (Floor, Ceiling, Round, Round_Even);
  92    for Rounding_Mode use (0, 1, 2, 3);
  93    --  Used to indicate rounding mode for Machine attribute
  94    --  Note that C code in gigi knows that Round_Even is 3
  95
  96    --  The Machine attribute is special, in that it takes an extra argument
  97    --  indicating the rounding mode, and also an argument Enode that is a
  98    --  node used to post warnings (e.g. if asked to convert a negative zero
  99    --  on a machine for which Signed_Zeros is False).
 100
 101    function Machine
 102      (RT    : R;
 103       X     : T;
 104       Mode  : Rounding_Mode;
 105       Enode : Node_Id) return T;
 106
 107 end Eval_Fat;