entity ch_02_01 is end entity ch_02_01; ---------------------------------------------------------------- architecture test of ch_02_01 is begin section_2_1_a : process is -- code from book: constant number_of_bytes : integer := 4; constant number_of_bits : integer := 8 * number_of_bytes; constant e : real := 2.718281828; constant prop_delay : time := 3 ns; constant size_limit, count_limit : integer := 255; -- variable index : integer := 0; variable sum, average, largest : real; variable start, finish : time := 0 ns; -- end of code from book begin wait; end process section_2_1_a; ---------------- section_2_1_b : process is -- code from book: variable start : time := 0 ns; variable finish : time := 0 ns; -- end of code from book variable program_counter : integer; variable index : integer; begin -- code from book: program_counter := 0; index := index + 1; -- end of code from book wait; end process section_2_1_b; ---------------- section_2_2_a : process is -- code from book: type apples is range 0 to 100; type oranges is range 0 to 100; -- type day_of_month is range 0 to 31; type year is range 0 to 2100; variable today : day_of_month := 9; variable start_year : year := 1987; -- constant number_of_bits : integer := 32; type bit_index is range 0 to number_of_bits - 1; -- type set_index_range is range 21 downto 11; type mode_pos_range is range 5 to 7; variable set_index : set_index_range; variable mode_pos : mode_pos_range; -- type input_level is range -10.0 to +10.0; type probability is range 0.0 to 1.0; -- variable input_A : input_level; -- end of code from book begin -- code from book: -- error: Incompatible types for assignment -- start_year := today; -- end of code from book wait; end process section_2_2_a; ---------------- section_2_2_b : process is -- code from book: type resistance is range 0 to 1E9 units ohm; end units resistance; -- end of code from book begin wait; end process section_2_2_b; ---------------- section_2_2_c : process is -- code from book: type resistance is range 0 to 1E9 units ohm; kohm = 1000 ohm; Mohm = 1000 kohm; end units resistance; -- end of code from book begin wait; end process section_2_2_c; ---------------- section_2_2_d : process is -- code from book: type length is range 0 to 1E9 units um; -- primary unit: micron mm = 1000 um; -- metric units m = 1000 mm; mil = 254 um; -- imperial units inch = 1000 mil; end units length; -- end of code from book begin wait; end process section_2_2_d; ---------------- section_2_2_e : process is -- code from book: -- type time is range implementation_defined type time is range integer'low to integer'high units fs; ps = 1000 fs; ns = 1000 ps; us = 1000 ns; ms = 1000 us; sec = 1000 ms; min = 60 sec; hr = 60 min; end units; -- end of code from book begin wait; end process section_2_2_e; ---------------- section_2_2_f : process is -- code from book: type alu_function is (disable, pass, add, subtract, multiply, divide); -- type octal_digit is ('0', '1', '2', '3', '4', '5', '6', '7'); -- variable alu_op : alu_function; variable last_digit : octal_digit := '0'; -- type logic_level is (unknown, low, undriven, high); variable control : logic_level; type water_level is (dangerously_low, low, ok); variable water_sensor : water_level; -- end of code from book begin -- code from book: alu_op := subtract; last_digit := '7'; -- control := low; water_sensor := low; -- end of code from book wait; end process section_2_2_f; ---------------- section_2_2_g : process is -- code from book: type severity_level is (note, warning, error, failure); -- end of code from book begin wait; end process section_2_2_g; ---------------- section_2_2_h : process is -- code from book: variable cmd_char, terminator : character; -- end of code from book begin -- code from book: cmd_char := 'P'; terminator := cr; -- end of code from book wait; end process section_2_2_h; ---------------- section_2_2_i : process is -- code from book: type boolean is (false, true); -- type bit is ('0', '1'); -- end of code from book begin wait; end process section_2_2_i; ---------------- section_2_2_j : process is variable write_enable_n, select_reg_n, write_reg_n : bit; begin -- code from book: write_reg_n := not ( not write_enable_n and not select_reg_n ); -- end of code from book wait; end process section_2_2_j; ---------------- section_2_2_k : process is -- code from book: type std_ulogic is ( 'U', -- Uninitialized 'X', -- Forcing Unknown '0', -- Forcing zero '1', -- Forcing one 'Z', -- High Impedance 'W', -- Weak Unknown 'L', -- Weak zero 'H', -- Weak one '-' ); -- Don't care -- end of code from book begin wait; end process section_2_2_k; ---------------- section_2_3_a : process is -- code from book: subtype small_int is integer range -128 to 127; -- variable deviation : small_int; variable adjustment : integer; -- subtype bit_index is integer range 31 downto 0; -- end of code from book begin deviation := 0; adjustment := 0; -- code from book: deviation := deviation + adjustment; -- end of code from book wait; end process section_2_3_a; ---------------- section_2_3_b : process is constant highest_integer : integer := integer'high; constant highest_time : time := time'high; -- code from book: subtype natural is integer range 0 to highest_integer; subtype positive is integer range 1 to highest_integer; -- subtype delay_length is time range 0 fs to highest_time; -- end of code from book begin wait; end process section_2_3_b; ---------------- section_2_3_c : process is -- code from book: type logic_level is (unknown, low, undriven, high); type system_state is (unknown, ready, busy); -- subtype valid_level is logic_level range low to high; -- end of code from book begin wait; end process section_2_3_c; ---------------- section_2_4_a : process is -- code from book: type resistance is range 0 to 1E9 units ohm; kohm = 1000 ohm; Mohm = 1000 kohm; end units resistance; type set_index_range is range 21 downto 11; type logic_level is (unknown, low, undriven, high); -- end of code from book begin -- output from vsim: "2000" report resistance'image(2 kohm); -- code from book: assert resistance'left = 0 ohm; assert resistance'right = 1E9 ohm; assert resistance'low = 0 ohm; assert resistance'high = 1E9 ohm; assert resistance'ascending = true; assert resistance'image(2 kohm) = "2000 ohm"; assert resistance'value("5 Mohm") = 5_000_000 ohm; assert set_index_range'left = 21; assert set_index_range'right = 11; assert set_index_range'low = 11; assert set_index_range'high = 21; assert set_index_range'ascending = false; assert set_index_range'image(14) = "14"; assert set_index_range'value("20") = 20; assert logic_level'left = unknown; assert logic_level'right = high; assert logic_level'low = unknown; assert logic_level'high = high; assert logic_level'ascending = true; assert logic_level'image(undriven) = "undriven"; assert logic_level'value("Low") = low; -- assert logic_level'pos(unknown) = 0; assert logic_level'val(3) = high; assert logic_level'succ(unknown) = low; assert logic_level'pred(undriven) = low; -- assert time'pos(4 ns) = 4_000_000; -- end of code from book wait; end process section_2_4_a; ---------------- section_2_4_b : process is -- code from book: type length is range integer'low to integer'high units mm; end units length; type area is range integer'low to integer'high units square_mm; end units area; -- variable L1, L2 : length; variable A : area; -- end of code from book begin -- code from book: -- error: No feasible entries for infix op: "*" -- A := L1 * L2; -- this is incorrect -- A := area'val( length'pos(L1) * length'pos(L2) ); -- end of code from book wait; end process section_2_4_b; ---------------- section_2_4_c : process is -- code from book: type opcode is (nop, load, store, add, subtract, negate, branch, halt); subtype arith_op is opcode range add to negate; -- end of code from book begin -- code from book: assert arith_op'base'left = nop; assert arith_op'base'succ(negate) = branch; -- end of code from book wait; end process section_2_4_c; end architecture test;