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发表于 2012-2-22 10:36:18
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是引用的意思,和ref是一个意思,你可以认为就是重新取了个名字,其实是同一个东西,既不是赋值也不是同步。
在IEEE1800-2009标准里有这么一段话:(注意看了,说的是refers to而不是assigns to或者syncs to)
Example:
clocking bus @(posedge clock1);
default input #10ns output #2ns;
input data, ready, enable = top.mem1.enable;
output negedge ack;
input #1step addr;
endclocking
In the above example, the first line declares a clocking block called bus that is to be clocked on the positive
edge of the signal clock1. The second line specifies that by default all signals in the clocking block shall
use a 10ns input skew and a 2ns output skew. The next line adds three input signals to the clocking block:
data, ready, and enable; the last signal refers to the hierarchical signal top.mem1.enable. The fourth
line adds the signal ack to the clocking block and overrides the default output skew so that ack is driven on
the negative edge of the clock. The last line adds the signal addr |
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