entity fg_04_03 is
end entity fg_04_03;
----------------------------------------------------------------
architecture test of fg_04_03 is
begin
-- code from book:
modem_controller : process is
type symbol is ('a', 't', 'd', 'h', digit, cr, other);
type symbol_string is array (1 to 20) of symbol;
type state is range 0 to 6;
type transition_matrix is array (state, symbol) of state;
constant next_state : transition_matrix :=
( 0 => ('a' => 1, others => 6),
1 => ('t' => 2, others => 6),
2 => ('d' => 3, 'h' => 5, others => 6),
3 => (digit => 4, others => 6),
4 => (digit => 4, cr => 0, others => 6),
5 => (cr => 0, others => 6),
6 => (cr => 0, others => 6) );
variable command : symbol_string;
variable current_state : state := 0;
-- not in book:
type sample_array is array (positive range <>) of symbol_string;
constant sample_command : sample_array :=
( 1 => ( 'a', 't', 'd', digit, digit, cr, others => other ),
2 => ( 'a', 't', 'h', cr, others => other ),
3 => ( 'a', 't', other, other, cr, others => other ) );
-- end not in book
begin
-- . . .
-- not in book:
for command_index in sample_command'range loop
command := sample_command(command_index);
-- end not in book
for index in 1 to 20 loop
current_state := next_state( current_state, command(index) );
case current_state is
-- . . .
-- not in book:
when 0 => exit;
when others => null;
-- end not in book
end case;
end loop;
-- . . .
-- not in book:
end loop;
wait;
-- end not in book
end process modem_controller;
-- end of code from book
end architecture test;
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