proc.vhd

来自「用VHDL编写的数字时钟,可变宽度脉冲产生器」· VHDL 代码 · 共 32 行

-- MAX+plus II VHDL Example
-- Combinatorial Process Statement
-- Copyright (c) 1994 Altera Corporation

ENTITY proc IS
	PORT
	(
		d	: IN BIT_VECTOR (2 DOWNTO 0);
		q	: OUT INTEGER RANGE 0 TO 3
	);
END proc;

ARCHITECTURE maxpld OF proc IS
BEGIN

	PROCESS (d)       -- count the number of bits with the value 1 in word d
	    VARIABLE num_bits : INTEGER;
	BEGIN
	    num_bits := 0;
	
	    FOR i IN d'RANGE LOOP
	        IF d(i) = '1' THEN
	            num_bits := num_bits + 1;
	        END IF;
	    END LOOP;
	
	    q <= num_bits;
	END PROCESS;

END maxpld;