gcc/ada/s-fatgen.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                       S Y S T E M . F A T _ G E N                        --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --                                                                          --
  10 --          Copyright (C) 1992-2001 Free Software Foundation, Inc.          --
  11 --                                                                          --
  12 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  13 -- terms of the  GNU General Public License as published  by the Free Soft- --
  14 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  15 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  16 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  17 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  18 -- for  more details.  You should have  received  a copy of the GNU General --
  19 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  20 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  21 -- MA 02111-1307, USA.                                                      --
  22 --                                                                          --
  23 -- As a special exception,  if other files  instantiate  generics from this --
  24 -- unit, or you link  this unit with other files  to produce an executable, --
  25 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  26 -- covered  by the  GNU  General  Public  License.  This exception does not --
  27 -- however invalidate  any other reasons why  the executable file  might be --
  28 -- covered by the  GNU Public License.                                      --
  29 --                                                                          --
  30 -- GNAT was originally developed  by the GNAT team at  New York University. --
  31 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  32 --                                                                          --
  33 ------------------------------------------------------------------------------
  34
  35 --  This generic package provides a target independent implementation of the
  36 --  floating-point attributes that denote functions. The implementations here
  37 --  are portable, but very slow. The runtime contains a set of instantiations
  38 --  of this package for all predefined floating-point types, and these should
  39 --  be replaced by efficient assembly language code where possible.
  40
  41 generic
  42     type T is digits <>;
  43
  44 package System.Fat_Gen is
  45 pragma Pure (Fat_Gen);
  46
  47    subtype UI is Integer;
  48    --  The runtime representation of universal integer for the purposes of
  49    --  this package is integer. The expander generates conversions for the
  50    --  actual type used. For functions returning universal integer, there
  51    --  is no problem, since the result always is in range of integer. For
  52    --  input arguments, the expander has to do some special casing to deal
  53    --  with the (very annoying!) cases of out of range values. If we used
  54    --  Long_Long_Integer to represent universal, then there would be no
  55    --  problem, but the resulting inefficiency would be annoying.
  56
  57    function Adjacent          (X, Towards : T)              return T;
  58
  59    function Ceiling           (X : T)                       return T;
  60
  61    function Compose           (Fraction : T; Exponent : UI) return T;
  62
  63    function Copy_Sign         (Value, Sign : T)             return T;
  64
  65    function Exponent          (X : T)                       return UI;
  66
  67    function Floor             (X : T)                       return T;
  68
  69    function Fraction          (X : T)                       return T;
  70
  71    function Leading_Part      (X : T; Radix_Digits : UI)    return T;
  72
  73    function Machine           (X : T)                       return T;
  74
  75    function Model             (X : T)                       return T;
  76
  77    function Pred              (X : T)                       return T;
  78
  79    function Remainder         (X, Y : T)                    return T;
  80
  81    function Rounding          (X : T)                       return T;
  82
  83    function Scaling           (X : T; Adjustment : UI)      return T;
  84
  85    function Succ              (X : T)                       return T;
  86
  87    function Truncation        (X : T)                       return T;
  88
  89    function Unbiased_Rounding (X : T)                       return T;
  90
  91    function Valid (X : access T) return Boolean;
  92    --  This function checks if the object of type T referenced by X
  93    --  is valid, and returns True/False accordingly. The parameter is
  94    --  passed by reference (access) here, as the object of type T may
  95    --  be an abnormal value that cannot be passed in a floating-point
  96    --  register, and the whole point of 'Valid is to prevent exceptions.
  97
  98 private
  99    pragma Inline (Machine);
 100    pragma Inline (Model);
 101    pragma Inline_Always (Valid);
 102
 103 end System.Fat_Gen;