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└─⟦180fe333a⟧ Bits:30000405 8mm tape, Rational 1000, SW CATALOG, 10_20_0
└─⟦180fe333a⟧ Bits:30000537 8mm tape, Rational 1000, SW Catalog 10_20_0
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TextFile

with Instrument;
use Instrument;

----------------
-- Sparse Case 1..5
----------------

-- These five tests evaluate the code efficiency of a sparse case
-- statement, i.e., one in which the case alternatives are selected
-- by two choice values from an extensive range of case expression values,
-- in which the difference between the values is varied for each test.

-- The purpose of these tests is to offer the compiler different case
-- statements that may be implemented by explicit comparison with the
-- choice values or with a jump table when the difference between the
-- two choice values is small.

-- The global variable is used in the case expression to select one
-- of the three alternatives that are included in the case statement.
-- In the test version, each alternative is explicitly specified by
-- a range of consecutive values and comprises a camouflaged assignment
-- of the first value in the choice range to the global variable.
-- The value of the case expression will always cause execution of the
-- first case alternative; however, this condition is carefully protected
-- from detection by the compiler so that no optimization of the case
-- statement is performed.  In the noise version, the case statement
-- is removed to leave an if-then-else construct comprising an
-- equivalent number of assignments so that the code efficiency can be
-- derived.

procedure Cssta2 is

    package New_Procs is new Procs (Integer);
    use New_Procs;

begin

    Start ("CSSTA2", "Case Statement Sparse Test w/range 1..5 (test)");
    for I in 1 .. 10000 loop

        Let (Global, Ident (1));
        case Global is
            when 1 =>
                if Global = Ident (1) then
                    -- always true
                    Let (Global, Ident (1));
                else
                    Let (Global, Ident (0));
                end if;                                -- included in test version
            when 5 =>
                Let (Global, Ident (5));
            when others =>
                null;
                --    end if;                                -- included in control version
        end case;

    end loop;
    Stop;

end Cssta2;