Ada Programming/Libraries/System.Atomic Operations.Modular Arithmetic

This language feature has been introduced in Ada 2022.

System.Atomic Operations.Modular_Arithmetic is a unit of the Predefined Language Environment since Ada 2022.

generic
   type Atomic_Type is mod <> with Atomic;
package System.Atomic_Operations.Modular_Arithmetic
   with Pure, Nonblocking is

   procedure Atomic_Add (Item  : aliased in out Atomic_Type;
                         Value : Atomic_Type)
      with Convention => Intrinsic;

   procedure Atomic_Subtract (Item  : aliased in out Atomic_Type;
                              Value : Atomic_Type)
      with Convention => Intrinsic;

   function Atomic_Fetch_And_Add
     (Item  : aliased in out Atomic_Type;
      Value : Atomic_Type) return Atomic_Type
      with Convention => Intrinsic;

   function Atomic_Fetch_And_Subtract
     (Item  : aliased in out Atomic_Type;
      Value : Atomic_Type) return Atomic_Type
      with Convention => Intrinsic;

   function Is_Lock_Free (Item : aliased Atomic_Type) return Boolean
      with Convention => Intrinsic;

end System.Atomic_Operations.Modular_Arithmetic;

The operations of this package are defined as follows:

procedure Atomic_Add (Item  : aliased in out Atomic_Type;
                      Value : Atomic_Type)
   with Convention => Intrinsic;

Atomically performs: Item := Item + Value;

procedure Atomic_Subtract (Item  : aliased in out Atomic_Type;
                           Value : Atomic_Type)
   with Convention => Intrinsic;

Atomically performs: Item := Item - Value;

function Atomic_Fetch_And_Add
  (Item  : aliased in out Atomic_Type;
   Value : Atomic_Type) return Atomic_Type
   with Convention => Intrinsic;

Atomically performs: Tmp := Item; Item := Item + Value; return Tmp;

function Atomic_Fetch_And_Subtract
  (Item  : aliased in out Atomic_Type;
   Value : Atomic_Type) return Atomic_Type
   with Convention => Intrinsic;

Atomically performs: Tmp := Item; Item := Item - Value; return Tmp;