File : s-arit64.ads
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-- GNAT COMPILER COMPONENTS --
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35
-- 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.
40 with Interfaces;
package System.Arith_64 is
pragma Pure (Arith_64);
45 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.
50
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.
55 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
60 (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,
65 -- 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.
70
procedure Double_Divide
(X, Y, Z : Int64;
Q, R : out Int64;
Round : Boolean);
75 -- 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
80 -- 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;