基于微指令覆盖的最小指令集测试算法

A Minimum Instruction Set Testing Algorithm Based on Microinstruction Coverage

着重讨论了如何利用微处理器中的自测试设计来缩短功能测试序列的长度 .首先 ,依据指令的表示模型 ,将指令测试分成微指令序列和微指令执行两个测试层次 ,提出了一个基于微指令覆盖的最小指令集测试算法 ,只需检测指令集的一个子集就能达到指令测试的目的 .然后 ,通过定义指令的测试代价和测试效率 ,提出了一个可以有效地选择最小测试指令集的方法 .最后 ,将算法应用于 NRS40 0 0微处理器的功能测试 ,仅为传统的全指令集测试序列的 37.7% .

Modern microprocessor integrates many millions of transistors, with embedded functions such as large register file and Cache, with a small number of test points, requires the additional design for testability, to simplify test pattern generation and decrease test complexity. This paper emphasizes in how to shorten the length of functional testing sequence by making use of Buit In Self Test in microprocessors. Firstly, the instruction testing is decompounded into microinstruction sequencing level and microinstruction executing level, according to the instruction representation and fault model, and the effect of BIST is discussed. Secondly, a minimum instruction set testing algorithm based on microinstruction coverage is presented. In which, only instructions in the minimum sub set of instruction set be tested to complete the task of instruction testing. Then an algorithm to effectively choose the minimum sub set of instruction set is given after defining the test cost and test efficiency of an instruction. The result of using the algorithm in the development of NRS4000 microprocessor's functional testing program. Shows that it decreases 62% comparing with traditional algorithm. Finally, some conclusions are given.