Caltech Intermediate Form

Caltech Intermediate Form (CIF) is a file format for describing integrated circuits.CIF provides a limited set of graphics primitives that are useful for describing the two-dimensionalshapes on the different layers of a chip.The format allows hierarchical description, which makes the representation concise.In addition, it is a terse but human-readable text format.

Overview

Each statement in CIF consists of a keyword or letter followed by parameters and terminatedwith a semicolon.Spaces must separate the parameters but there are no restrictions on the number of statementsper line or of the particular columns of any field.Comments can be inserted anywhere by enclosing them in parenthesis.

There are only a few CIF statements and they fall into one of two categories: geometry or control.The geometry statements are: <CODE>LAYER</CODE> to switch mask layers, <CODE>BOX</CODE> to draw arectangle, <CODE>WIRE</CODE> to draw a path, <CODE>ROUNDFLASH</CODE> to draw a circle, <CODE>POLYGON</CODE> to draw an arbitraryfigure, and <CODE>CALL</CODE> to draw a subroutine of other geometry statements.The control statements are <CODE>DS</CODE> to start the definition of a subroutine, <CODE>DF</CODE> to finish thedefinition of a subroutine, <CODE>DD</CODE> to delete the definition of subroutines, <CODE>0</CODE> through <CODE>9</CODE> toinclude additional...
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