projects / thirdparty / gcc.git / blame
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|---|---|---|
| cacbc350 RK |
1 | ------------------------------------------------------------------------------ |
| 2 | -- -- | |
| 3084fecd | 3 | -- GNAT RUN-TIME COMPONENTS -- |
| cacbc350 | 4 | -- -- |
| fbf5a39b | 5 | -- S Y S T E M . E X N _ I N T -- |
| cacbc350 | 6 | -- -- |
| fbf5a39b | 7 | -- B o d y -- |
| cacbc350 | 8 | -- -- |
| 4b490c1e | 9 | -- Copyright (C) 1992-2020, Free Software Foundation, Inc. -- |
| cacbc350 RK |
10 | -- -- |
| 11 | -- GNAT is free software; you can redistribute it and/or modify it under -- | |
| 12 | -- terms of the GNU General Public License as published by the Free Soft- -- | |
| 748086b7 | 13 | -- ware Foundation; either version 3, or (at your option) any later ver- -- |
| cacbc350 RK |
14 | -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- |
| 15 | -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- | |
| 748086b7 JJ |
16 | -- or FITNESS FOR A PARTICULAR PURPOSE. -- |
| 17 | -- -- | |
| 18 | -- As a special exception under Section 7 of GPL version 3, you are granted -- | |
| 19 | -- additional permissions described in the GCC Runtime Library Exception, -- | |
| 20 | -- version 3.1, as published by the Free Software Foundation. -- | |
| 21 | -- -- | |
| 22 | -- You should have received a copy of the GNU General Public License and -- | |
| 23 | -- a copy of the GCC Runtime Library Exception along with this program; -- | |
| 24 | -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- | |
| 25 | -- <http://www.gnu.org/licenses/>. -- | |
| cacbc350 RK |
26 | -- -- |
| 27 | -- GNAT was originally developed by the GNAT team at New York University. -- | |
| 71ff80dc | 28 | -- Extensive contributions were provided by Ada Core Technologies Inc. -- |
| cacbc350 RK |
29 | -- -- |
| 30 | ------------------------------------------------------------------------------ | |
| 31 | ||
| fbf5a39b | 32 | package body System.Exn_Int is |
| cacbc350 | 33 | |
| fbf5a39b AC |
34 | ----------------- |
| 35 | -- Exn_Integer -- | |
| 36 | ----------------- | |
| cacbc350 | 37 | |
| 08aa9a4a | 38 | function Exn_Integer (Left : Integer; Right : Natural) return Integer is |
| fbf5a39b AC |
39 | pragma Suppress (Division_Check); |
| 40 | pragma Suppress (Overflow_Check); | |
| cacbc350 | 41 | |
| fbf5a39b AC |
42 | Result : Integer := 1; |
| 43 | Factor : Integer := Left; | |
| 44 | Exp : Natural := Right; | |
| cacbc350 | 45 | |
| fbf5a39b AC |
46 | begin |
| 47 | -- We use the standard logarithmic approach, Exp gets shifted right | |
| 48 | -- testing successive low order bits and Factor is the value of the | |
| 49 | -- base raised to the next power of 2. | |
| cacbc350 | 50 | |
| fbf5a39b AC |
51 | -- Note: it is not worth special casing base values -1, 0, +1 since |
| 52 | -- the expander does this when the base is a literal, and other cases | |
| 53 | -- will be extremely rare. | |
| cacbc350 | 54 | |
| fbf5a39b AC |
55 | if Exp /= 0 then |
| 56 | loop | |
| 57 | if Exp rem 2 /= 0 then | |
| 58 | Result := Result * Factor; | |
| 59 | end if; | |
| cacbc350 | 60 | |
| fbf5a39b AC |
61 | Exp := Exp / 2; |
| 62 | exit when Exp = 0; | |
| 63 | Factor := Factor * Factor; | |
| 64 | end loop; | |
| 65 | end if; | |
| 66 | ||
| 67 | return Result; | |
| 68 | end Exn_Integer; | |
| cacbc350 | 69 | |
| fbf5a39b | 70 | end System.Exn_Int; |