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entity func_test3 is
generic (NBITS: natural := 6);
end entity;
architecture fum of func_test3 is
type remains is (r0, r1, r2, r3, r4); -- remainder values
function mod5 (dividend: bit_vector) return boolean is
type remain_array is array (NBITS downto 0) of remains;
type branch is array (remains, bit) of remains;
constant br_table: branch := ( r0 => ('0' => r0, '1' => r1),
r1 => ('0' => r2, '1' => r3),
r2 => ('0' => r4, '1' => r0),
r3 => ('0' => r1, '1' => r2),
r4 => ('0' => r3, '1' => r4)
);
variable remaind: remains := r0;
variable tbit: bit_vector (NBITS - 1 downto 0) := dividend;
begin
for i in dividend'length - 1 downto 0 loop
remaind := br_table(remaind,tbit(i));
end loop;
return remaind = r0;
end function;
begin
assert mod5("101000");
end architecture;
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