Wol and Wolcomp

Wol is a graphical environment for IC mask layout. Wolcomp is a simple cell compiler, embedded in C, for the compilation of leaf cells generated by Wol into a complete chip. The original versions of Wol and Wolcomp were written by Carver Mead; the version included in the Chipmunk package was primarily written by Massimo Sivilotti, with major contributions by Glenn Gribble. The name Wol originates from the children's book Winnie the Pooh. Features of Wol and Wolcomp include:
Cell editing
The Manhattan-geometry leaf-cell editor in Wol has two major differences (advantages or disadvantages depending on your preferences) compared with Magic: CIF layers are drawn directly, and box drawing uses a rubber-banding interface. Preferences concerning the mechanics of drawing layout is a primary reason users avoid or embrace Wol.
Cell composition
Wolcomp, a simple cell compiler embedded in C, supports composition of leaf cells drawn by Wol under program control, allowing the construction of parameterizable macrocell generators. Wol includes an full-featured viewer of Wolcomp compositions that also supports manual composition; however, manual composition in Wol is rudimentary and not suitable for large manually-composed designs.
Netlist extraction
Wol includes a netlist extraction function, that produces netlist files suitable for net comparison with schematic netlists generated by Log. Dense 4600 micron by 6800 micron chips (lambda = 1 micron), with over 50,000 transistors, have been successfully extracted with Wol. Wol supports post-extraction visualization of netlist connectivity.
Rudimentary DRC
The Wol leaf-cell editor and composition viewer supports rudimentary post-layout DRC, but cannot DRC entire chips. Wol designers typically use Magic (or another tool) to do a full-layout DRC before tapeout. Tools exist to convert Wol CIF output to a form compatible with Magic, and to create flattened CIF for use in Magic DRC checking.

Wol and Wolcomp have relatively few users, due to the popularity of Magic and the commercial tool LEdit. Some users do use Wol extensively to create IC designs for fabrication through MOSIS; I have designed over 20 chips using Wol and Wolcomp since the Unix port of the Chipmunk tools, using Magic for auxiliary DRC purposes only. For some users, the advantages of cell compilation outweigh other issues.

To learn more about Wol, you can start exploring its detailed documentation .

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