-- --
-- S p e c --
-- --
--- Copyright (C) 1992-2008, Free Software Foundation, Inc. --
+-- Copyright (C) 1992-2010, Free Software Foundation, Inc. --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
--- ware Foundation; either version 2, or (at your option) any later ver- --
+-- ware Foundation; either version 3, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
--- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
--- for more details. You should have received a copy of the GNU General --
--- Public License distributed with GNAT; see file COPYING. If not, write --
--- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
--- Boston, MA 02110-1301, USA. --
+-- or FITNESS FOR A PARTICULAR PURPOSE. --
-- --
--- As a special exception, if other files instantiate generics from this --
--- unit, or you link this unit with other files to produce an executable, --
--- this unit does not by itself cause the resulting executable to be --
--- covered by the GNU General Public License. This exception does not --
--- however invalidate any other reasons why the executable file might be --
--- covered by the GNU Public License. --
+-- As a special exception under Section 7 of GPL version 3, you are granted --
+-- additional permissions described in the GCC Runtime Library Exception, --
+-- version 3.1, as published by the Free Software Foundation. --
+-- --
+-- You should have received a copy of the GNU General Public License and --
+-- a copy of the GCC Runtime Library Exception along with this program; --
+-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
+-- <http://www.gnu.org/licenses/>. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- given Modulo (uses Euclid's algorithm). Note: the call is considered
-- to be erroneous (and the behavior is undefined) if n is not invertible.
- function UI_From_Dint (Input : Dint) return Uint;
- -- Converts Dint value to universal integer form
-
function UI_From_Int (Input : Int) return Uint;
-- Converts Int value to universal integer form
-- or decimal format. Auto, the default setting, lets the routine make
-- a decision based on the value.
- UI_Image_Max : constant := 32;
+ UI_Image_Max : constant := 48; -- Enough for a 128-bit number
UI_Image_Buffer : String (1 .. UI_Image_Max);
UI_Image_Length : Natural;
-- Buffer used for UI_Image as described below
-- Base is defined to allow efficient execution of the primitive operations
-- (a0, b0, c0) defined in the section "The Classical Algorithms"
-- (sec. 4.3.1) of Donald Knuth's "The Art of Computer Programming",
- -- Vol. 2. These algorithms are used in this package.
+ -- Vol. 2. These algorithms are used in this package. In particular,
+ -- the product of two single digits in this base fits in a 32-bit integer.
Base_Bits : constant := 15;
-- Number of bits in base value
Uint_Minus_80 : constant Uint := Uint (Uint_Direct_Bias - 80);
Uint_Minus_128 : constant Uint := Uint (Uint_Direct_Bias - 128);
+ Uint_Max_Simple_Mul : constant := Uint_Direct_Bias + 2 ** 15;
+ -- If two values are directly represented and less than or equal to this
+ -- value, then we know the product fits in a 32-bit integer. This allows
+ -- UI_Mul to efficiently compute the product in this case.
+
type Save_Mark is record
Save_Uint : Uint;
Save_Udigit : Int;
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