网站设计怎么做有效的,东莞网站建设网络公司公司,自然志wordpress,苏州创元投资集团网站在某些设计情况中,如果一些条件为真,则我们不想执行检验。换句话说,这就像是一个异步的复位,使得检验在当前时刻不工作。SVA提供了关键词“ disable iff来实现这种检验器的异步复位。“ disable iff”的基本语法如下。
disable iff (expression) property definition … 在某些设计情况中,如果一些条件为真,则我们不想执行检验。换句话说,这就像是一个异步的复位,使得检验在当前时刻不工作。SVA提供了关键词“ disable iff来实现这种检验器的异步复位。“ disable iff”的基本语法如下。
disable iff (expression) property definition 属性p34检查在有效开始后,信号“a”重复两次,且1个周期之后,信号“b”重复两次,再过一个时钟周期,信号“ start”为低。在整个序列过程中,如果“ reset”被检测为高,检验器会停止并默认地发出一个空成功的信号。
module disableiff;logic clk, reset, start;
logic a,b,c;initial $vcdpluson();initial
begin
clk1b0; reset1b0; start 1b0;
repeat(2) (posedge clk);
reset 1b1; a1b0; b1b0; c1b0;
repeat(2) (posedge clk) reset 1b0; start 1b1; (posedge clk) a1b1;
(posedge clk) a1b0;
repeat(2) (posedge clk);
(posedge clk) a1b1;
(posedge clk) a1b0;
repeat(2) (posedge clk);
(posedge clk) b1b1;
(posedge clk) b1b0;
repeat(2) (posedge clk);
(posedge clk) b1b1;
(posedge clk) b1b0;
repeat(1) (posedge clk);
start 1b0;
repeat(2) (posedge clk);start 1b1;(posedge clk) a1b1;
(posedge clk) a1b0;
repeat(2) (posedge clk);
(posedge clk) a1b1;
(posedge clk) a1b0;
repeat(2) (posedge clk);
(posedge clk) b1b1; reset 1b1;
(posedge clk) b1b0;
repeat(2) (posedge clk);
(posedge clk) b1b1;
(posedge clk) b1b0;
repeat(1) (posedge clk);
start 1b0;
repeat(2) (posedge clk);$finish();
endproperty p34;(posedge clk) disable iff (reset) $rose(start) | a[2] ##1 b[2] ##1 !start ;
endpropertya34: assert property(p34);initial forever clk #25 ~clk;endmodule图1-36显示了属性p34在模拟中的响应。标记1标出了一个有效的开始,在有效开始后,信号“a”重复为高两次,接着信号“b”重复为高两次,然后信号“ start”如期望的为低。 在整个序列的过程中,信号“ reset”如期望的始终不被激活,因此检验在标记1e处成功。第二个有效开始由标记2s标出。在有效开始后,信号“a”重复为高两次,接着复位信号“reet”在信号“b”重复两次之前被激活。这使得检查失效,属性得到一个空成功。
