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发表于 2005-7-28 17:56:46
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请问什么是regresssion simulation (无内容)
[这个贴子最后由jingli888ca在 2005/07/28 06:11pm 第 2 次编辑]
Regression simulation is defined as running all your test cases when a new fix is checked into your RTL database. This is the final step of simulation when developing an IC and is the most important one because it makes sure that all the modification after RTL freeze will not cause a new issue.
Regression normally takes long hours to do, sometimes, days, even weeks.
Therefore, there is a high level of requirements of the test cases such that they have to be sure to be correct, and it also requires good organization of test cases. Normally, it is done by perl scripts maintained by a perl Guru.
RTL passed regression is called Golden RTL, or pre-Golden RTL, depending on the companies. Normally, people often use PG1 (pre-Golden 1), PG2, etc to call the versions of RTL that pass the regression.
PGx appear when the board level emulation encounters bugs and the IC designers quickly deliver a fix. Even if the fix is very very small, the whole RTL has to go through the regression to make sure the fix does not cause any issues.
With PGx increasing to a bigger and bigger number, it is geting closer to the final RTL. At this time, it has to be decided whether or not to stop it. The main problem at this stage is that board emulation discovers some bugs that are OUT of spec, i.e., people who wrote the spec did not cover these issues. Should they be decided bugs? Or should they be left as a future feature enhencement? This is usually a serious decision made by management, architects and sales.
Anyway, I think this is enough for regression.
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