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This article introduces the knowledge of "what is KeyPoint Mapping status". In the operation of actual cases, many people will encounter such a dilemma. Then let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!

After Mapping, the point that pairs and binds successfully is called "Mapped Key Points"; all the points that are not paired or bound, or even if the pair is a "fake couple" are called "Unmapped Key Points". Happiness in this world is generally similar and there is nothing to describe, but unhappiness has its own loneliness, so it is worth exploring. "Unmapped Key Points" can be divided into three categories for different reasons:

Unreachable key points

Extra key points

Not-mapped key points

Unreachable key points:

This category is "fake couple" because they are not functional.

Serious definition: these key points will not fan out to any primary output port, nor will they fan out the input to any other timing unit, nor will they fan out any black box input.

Speaking of people: these key points, in the current mode, have no actual logic function for the whole circuit, they just occupy an area there and consume power.

Reason: one is that these key points have no logical function in this mode, but in other modes, the constraints set in this mode are dropped by bypass, such as DFT-related logic in function mode. The other is: it is dealt with by LEC modeling, such as clock gating cell, when setting "set flatten modeling-gated_clock", it will be LEC model into register D pin MUX;. The other kind is: these key points are really "dregs", they live meaninglessly and waste resources, most of them are caused by incomplete optimization of logic optimization tools.

Treatment: by default, LEC does not map unreachable key points, nor does it recommend map to unreachable key points. If you have to pair them with compassion, you can set the command "set mapping method-unreach" before map, which will increase the time of compare and lead to more fake non-eq points. If you only want to map a group of unreachable key poins, you can set it with the command "add mapped points".

Example: in the following example, because the SEL side is set to 0, the output of FF2 will never be propagated, becoming a key points of unreachable.

Extra key points:

This category is "the focus of heaven", because there is no object in life to match it.

Serious definition: these key points only exist in one of the Golden or Revised, not in both designs.

Speaking: these key poins may be primary input, primary output, DFF, Latch, they are either optimized redundant logic or added non-functional ports.

Categories and solutions:

As a result of wearing a waistcoat, is mistakenly regarded as "Tianzhu", for this category, users need to add some renaming rule to take off their waistcoat to help them match successfully.

New non-functional ports, such as PG pin added in the pendant phase, can be set to constant with the command "add pin constraints". For example, if DFT ports is added when synthesizing, this kind of ports does not belong to the category of logic function to be verified. If it is output ports, you can directly use the command "add ignored outputs" to expel it. If ignored is set, it will not be counted as any mapping status type. If it is input ports, if these input ports are the input of some key points, you need to use the command "add pin constraints" as a constraint according to the design intent, such as scan_enable, if these input ports do not fan out to any key points, you can directly ignore them or use the command "add ignored inputs" to drive them out.

For redundant DFF and Latch, if there is no special synthesis tool, the redundant logic will be optimized. In most cases, if the corresponding modeling option is set in LEC, LEC can identify the corresponding redundant logic and will modeling it. For some complex designs, before compare, LEC cannot confirm whether the Not-mapped DFF/Latch is redundant. During the compare process, the tool will do more in-depth analysis, and at the end of the comparison, the Not-mapped DFF/Latch will be classified into Extra key points. So you will see a change in the number of Extra key points before and after comparison on some case.

Not-mapped key points:

This category is "old difficulty". They have come to experience robbery, and they have to go through all kinds of difficulties before they can be matched successfully.

Serious definition: for a variety of reasons, LEC cannot easily find corresponding points to these key points in another design.

Say human words: this kind of key points may be either in Golden or in Revised. When there is no external assistance, LEC tries its best to find the corresponding points, and most of these points will lead to the failure of the comparison results, so it is necessary to apply all kinds of small magic to match them successfully before compare. There are only a few points, in the compare process, LEC found that they are not "old difficulties" but "orphans" or "fake couples" through in-depth understanding, and they will be classified as "orphans" or "fake couples" after compare.

Categories and solutions:

Because of wearing a vest, he does not recognize her, for this category, users need to add some renaming rule to take off their vest to help her match successfully.

The setting of modeling option is incomplete, and LEC does not model the optimization behavior of optimization tools, such as optimization actions: copy and merge of registers, optimized constant registers, optimization of "don't care" logic to the constant 0Universe 1, replacement of registers with master-slave latches, insertion and replication of clock gating cell, optimization of redundant registers, etc. For this type, you need to use "set flatten model" plus the corresponding option to solve; you can also use analyze_setup-effort to solve; you can also use set_analyze_option-effort_analyze_setup to solve; but note that the higher the runtime, the more runtime is used.

In some case, after all the above tricks fail, you need to use "remodel-notmapped"

"re-model and match the remaining points.

If all the above moves are used up and there are still notmapped points, first run a compare to determine whether there is a fake "old problem" hidden in it.

Impact:

"Old difficulty" is the kind of person who makes parents worry about their friends and has many negative effects on world harmony.

Not-mapped points will not be checked for logical equivalence as compared points; if they are not solved in the above steps, or if they are not resolved after an effort, the comparison result will be marked as "Incomplete".

If the Not-mapped point is the fan in of another key points, it will cause the verification result to fail, that is, Non-eq.

If the comparison result has no Non-eq and it can be proved that there is no corresponding point matching it, then the point of this kind of Not-mapped is harmless to humans and animals and can be ignored.

That's all for "what KeyPoint Mapping status is". Thank you for your reading. If you want to know more about the industry, you can follow the website, the editor will output more high-quality practical articles for you!

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