Caltech Intermediate Form - Control

Control

CIF subroutines can be overwritten by deleting them and then redefining them. The DD statement (delete definition) takes a single parameter and deletes every subroutine that has a number greater than or equal to this value. The statement is useful when merging multiple CIF files because designs can be defined, invoked, and deleted without causing naming conflicts. However, it is not recommended for general use by CAD systems.

Extensions to CIF can be done with the numeric statements 0 through 9. Although not officially part of CIF, certain conventions have evolved for the use of these extensions (see Fig. B.5).

0 x y layer N name; Set named node on specified layer and position
0V x1 y1 x2 y2 ... xn yn; Draw vectors
2A "msg" T x y; Place message above specified location
2B "msg" T x y; Place message below specified location
2C "msg" T x y; Place message centered at specified location
2L "msg" T x y; Place message left of specified location
2R "msg" T x y; Place message right of specified location
4A lowx lowy highx highy; Declare cell boundary
4B instancename; Attach instance name to cell
4N signalname x y; Labels a signal at a location
9 cellname; Declare cell name
91 instancename; Attach instance name to cell
94 label x y; Place label in specified location
95 label length width x y; Place label in specified area
FIGURE B.5 Typical user extensions to CIF.

The final statement in a CIF file is the END statement (or the letter E). It takes no parameters and typically does not include a semicolon.

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