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------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- S Y S T E M . D O U B L E _ R E A L . P R O D U C T --
-- --
-- B o d y --
-- --
-- Copyright (C) 2021-2022, 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 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. --
-- --
-- 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. --
-- --
------------------------------------------------------------------------------
-- This is the version of the separate package body for targets with an FMA
separate (System.Double_Real)
package body Product is
function Fused_Multiply_Add (A, B, C : Num) return Num;
-- Return the result of A * B + C without intermediate rounding
------------------------
-- Fused_Multiply_Add --
------------------------
function Fused_Multiply_Add (A, B, C : Num) return Num is
begin
case Num'Size is
when 32 =>
declare
function Do_FMA (A, B, C : Num) return Num;
pragma Import (Intrinsic, Do_FMA, "__builtin_fmaf");
begin
return Do_FMA (A, B, C);
end;
when 64 =>
declare
function Do_FMA (A, B, C : Num) return Num;
pragma Import (Intrinsic, Do_FMA, "__builtin_fma");
begin
return Do_FMA (A, B, C);
end;
when others =>
raise Program_Error;
end case;
end Fused_Multiply_Add;
--------------
-- Two_Prod --
--------------
function Two_Prod (A, B : Num) return Double_T is
P : constant Num := A * B;
E : Num;
begin
if Is_Infinity (P) or else Is_Zero (P) then
return (P, 0.0);
else
E := Fused_Multiply_Add (A, B, -P);
return (P, E);
end if;
end Two_Prod;
-------------
-- Two_Sqr --
-------------
function Two_Sqr (A : Num) return Double_T is (Two_Prod (A, A));
end Product;
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