文件名称：SystemVerilog Assertions - Design Tricks and SVA Bind Files_pres
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更新时间：2013-01-03 05:55:01
SystemVerilog Assertions - Design Tricks
There are some simple tricks that every design engineer should know to facilitate the usage of SystemVerilog Assertions. Although this paper is not intended to be a comprehensive tutorial on SystemVerilog Assertions, it is worthwhile to give a simplified definition of a property and the concurrent assertion of a property. 1.1 What is an assertion? An assertion is basically a "statement of fact" or "claim of truth" made about a design by a design or verification engineer. An engineer will assert or "claim" that certain conditions are always true or never true about a design. If that claim can ever be proven false, then the assertion fails (the "claim" was false). Assertions essentially become active design comments, and one important methodology treats them exactly like active design comments. More on this in Section 2. A trusted colleague and formal analysis expert[1] reports that for formal analysis, describing what should never happen using "not sequence" assertions is even more important than using assertions to describe always true conditions. 1.2 What is a property? A property is basically a rule that will be asserted (enabled) to passively test a design. The property can be a simple Boolean test regarding conditions that should always hold true about the design, or it can be a sampled sequence of signals that should follow a legal and prescribed protocol. For formal analysis, a property describes the environment of the block under verification, i.e. what is legal behavior of the inputs. 1.3 Two types of SystemVerilog assertions SystemVerilog has two types of assertions: (1) Immediate assertions (2) Concurrent assertions Immediate assertions execute once and are placed inline with the code. Immediate assertions are not exceptionally useful except in a few places, which are detailed in Section 3.