Calligrapher: a new layout-migration engine for hard intellectual property libraries
Bibliographic record
Abstract
Modern systems-on-a-chip depend heavily on hard intellectual properties, such as standard cell and datapath libraries. As the foundries accelerate their update of advanced processes with increasingly complex design rules, and the libraries grow in flexibility and size, the cost of library development becomes prohibitively high. Automated layout-migration techniques used today, which are based on layout compaction developed a decade ago, corrupt advanced design considerations by honoring only design rules, and cannot cope with some of the new challenges involved. In this paper, we present a new integer linear programming (ILP)-based layout-migration engine, called calligrapher, and make the following contributions. First, we extend the recently proposed minimum perturbation (MP) metric designed to retain original layout design intentions, while overcoming its shortcoming of biased treatment of layout objects. Second, we propose a new design-rule-constraint algorithm, and prove its linear complexity for the number of constraints generated. Compared with what has been achieved in the literature, the proposed algorithm can significantly reduce the ILP solver time by limiting the constraint size. Third, we propose an iterative migration framework based on the concept of soft constraint. With this framework, two-dimensional compaction quality can be achieved with a runtime comparable to one-dimensional compaction. We demonstrate the effectiveness of calligrapher by migrating the Berkeley low-power libraries, originally developed for the 1.2-/spl mu/m MOSIS process, into TSMC 0.25- and 0.18-/spl mu/m technologies. We show that even for a very compact layout, our metric and the MP metric can make a difference by as much as 20%-45%. We also show that our iterative algorithm can improve the area by 10% on average compared to the traditional technique using the MP metric, and inflates the area by merely 7.5% compared to the traditional technique using minimum-area metric.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".