vhdl case/when:多个事例,单个子句

可以使用“管道”或条形符号分隔多个选项。示例的正确语法是:

CASE res IS
  WHEN "00" | "01" => Y <= A;
  WHEN "10" => Y <= B;
  WHEN "11" => Y <= C;
  WHEN OTHERS => Y <= 'X';
END CASE;

您还可以为案例提供一系列选择:

USE IEEE.STD_LOGIC_ARITH.ALL;

CASE CONV_INTEGER(res) IS
  WHEN 0 to 1 => Y <= A;
  WHEN 2 => Y <= B;
  WHEN 3 => Y <= C;
  WHEN OTHERS => Y <= 'X';
END CASE;