------------------------------------------------------------------------------ | |

-- -- | |

-- GNAT COMPILER COMPONENTS -- | |

-- -- | |

-- S Y S T E M . A R I T H _ 6 4 -- | |

-- -- | |

-- S p e c -- | |

-- -- | |

-- Copyright (C) 1994,1995,1996 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- -- | |

-- 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, 59 Temple Place - Suite 330, Boston, -- | |

-- MA 02111-1307, USA. -- | |

-- -- | |

-- 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. -- | |

-- -- | |

-- GNAT was originally developed by the GNAT team at New York University. -- | |

-- Extensive contributions were provided by Ada Core Technologies Inc. -- | |

-- -- | |

------------------------------------------------------------------------------ | |

-- This unit provides software routines for doing arithmetic on 64-bit | |

-- signed integer values in cases where either overflow checking is | |

-- required, or intermediate results are longer than 64 bits. | |

with Interfaces; | |

package System.Arith_64 is | |

pragma Pure (Arith_64); | |

subtype Int64 is Interfaces.Integer_64; | |

function Add_With_Ovflo_Check (X, Y : Int64) return Int64; | |

-- Raises Constraint_Error if sum of operands overflows 64 bits, | |

-- otherwise returns the 64-bit signed integer sum. | |

function Subtract_With_Ovflo_Check (X, Y : Int64) return Int64; | |

-- Raises Constraint_Error if difference of operands overflows 64 | |

-- bits, otherwise returns the 64-bit signed integer difference. | |

function Multiply_With_Ovflo_Check (X, Y : Int64) return Int64; | |

-- Raises Constraint_Error if product of operands overflows 64 | |

-- bits, otherwise returns the 64-bit signed integer difference. | |

procedure Scaled_Divide | |

(X, Y, Z : Int64; | |

Q, R : out Int64; | |

Round : Boolean); | |

-- Performs the division of (X * Y) / Z, storing the quotient in Q | |

-- and the remainder in R. Constraint_Error is raised if Z is zero, | |

-- or if the quotient does not fit in 64-bits. Round indicates if | |

-- the result should be rounded. If Round is False, then Q, R are | |

-- the normal quotient and remainder from a truncating division. | |

-- If Round is True, then Q is the rounded quotient. the remainder | |

-- R is not affected by the setting of the Round flag. | |

procedure Double_Divide | |

(X, Y, Z : Int64; | |

Q, R : out Int64; | |

Round : Boolean); | |

-- Performs the division X / (Y * Z), storing the quotient in Q and | |

-- the remainder in R. Constraint_Error is raised if Y or Z is zero. | |

-- Round indicates if the result should be rounded. If Round is False, | |

-- then Q, R are the normal quotient and remainder from a truncating | |

-- division. If Round is True, then Q is the rounded quotient. The | |

-- remainder R is not affected by the setting of the Round flag. The | |

-- result is known to be in range except for the noted possibility of | |

-- Y or Z being zero, so no other overflow checks are required. | |

end System.Arith_64; |