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1 ------------------------------------------------------------------------------
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2 -- --
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3 -- GNAT RUN-TIME COMPONENTS --
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4 -- --
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5 -- S Y S T E M . A T O M I C _ C O U N T E R S --
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6 -- --
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7 -- B o d y --
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8 -- --
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145
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9 -- Copyright (C) 2011-2019, Free Software Foundation, Inc. --
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111
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10 -- --
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11 -- GNAT is free software; you can redistribute it and/or modify it under --
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12 -- terms of the GNU General Public License as published by the Free Soft- --
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13 -- ware Foundation; either version 3, or (at your option) any later ver- --
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14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
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15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
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16 -- or FITNESS FOR A PARTICULAR PURPOSE. --
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17 -- --
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18 -- As a special exception under Section 7 of GPL version 3, you are granted --
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19 -- additional permissions described in the GCC Runtime Library Exception, --
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20 -- version 3.1, as published by the Free Software Foundation. --
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21 -- --
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22 -- You should have received a copy of the GNU General Public License and --
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23 -- a copy of the GCC Runtime Library Exception along with this program; --
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24 -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
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25 -- <http://www.gnu.org/licenses/>. --
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26 -- --
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27 -- GNAT was originally developed by the GNAT team at New York University. --
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28 -- Extensive contributions were provided by Ada Core Technologies Inc. --
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29 -- --
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30 ------------------------------------------------------------------------------
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31
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32 -- This is version of the package, for use on platforms where this capability
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33 -- is not supported. All Atomic_Counter operations raises Program_Error,
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34 -- Atomic_Unsigned operations processed in non-atomic manner.
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35
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36 package body System.Atomic_Counters is
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37
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38 ---------------
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39 -- Decrement --
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40 ---------------
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41
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42 function Decrement (Item : in out Atomic_Counter) return Boolean is
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43 begin
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44 raise Program_Error;
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45 return False;
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46 end Decrement;
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47
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48 function Decrement (Item : aliased in out Atomic_Unsigned) return Boolean is
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49 begin
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50 -- Could not use Item := Item - 1; because it is disabled in spec.
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51 Item := Atomic_Unsigned'Pred (Item);
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52 return Item = 0;
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53 end Decrement;
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54
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55 procedure Decrement (Item : aliased in out Atomic_Unsigned) is
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56 begin
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57 Item := Atomic_Unsigned'Pred (Item);
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58 end Decrement;
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59
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60 ---------------
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61 -- Increment --
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62 ---------------
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63
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64 procedure Increment (Item : in out Atomic_Counter) is
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65 begin
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66 raise Program_Error;
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67 end Increment;
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68
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69 procedure Increment (Item : aliased in out Atomic_Unsigned) is
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70 begin
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71 Item := Atomic_Unsigned'Succ (Item);
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72 end Increment;
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73
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74 ----------------
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75 -- Initialize --
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76 ----------------
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77
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78 procedure Initialize (Item : out Atomic_Counter) is
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79 begin
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80 raise Program_Error;
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81 end Initialize;
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82
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83 ------------
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84 -- Is_One --
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85 ------------
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86
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87 function Is_One (Item : Atomic_Counter) return Boolean is
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88 begin
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89 raise Program_Error;
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90 return False;
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91 end Is_One;
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92
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93 end System.Atomic_Counters;
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