Virtuoso AMS Environment User Guide

Producing Customized Netlists

Data Objects Supported for Netlisting

The data used for netlisting is organized into objects. The AMS netlister objects include netlister, formatter, cellview, parameter, and instance. Each of these is described in detail in the following sections.

Netlister Object

The netlister object contains the global options applicable to the AMS netlister. You obtain the

ID of the netlister object by calling the amsGetNetlister function, with a command like

A_netlisterId = amsGetNetlister()

The netlister object is available throughout the life of the UNIX process that is running the AMS netlister and is a unique object for that process. The netlister object ID does not change as long as the process remains the same. However, the values of the fields of the netlister object can change with every netlist run as the netlister rereads the ams.env file.

Running a command like

A_netlisterId->?

you find that the netlister object contains the following fields. With the exception of thevlog and vhdl fields, each field corresponds to anams.env variable described in Appendix A, “Variables for ams.env Files.”

Virtuoso AMS Environment User Guide

Producing Customized Netlists

All of these fields are read-only. Attempting to change their values results in an error.

When you add new data to the database, be sure that the data adhere to the format and content requirements set by the values of these fields.

Formatter Object

The formatter object contains information about the netlist procedures for the formatter it represents. You use a command like the following to obtain the ID of the formatter:

A_formatterId = A_netlisterId->vlog

In this release, the only available formatter is the Verilog-AMS (vlog) formatter.

The formatter object is created when the vlog field of the netlister object is accessed for the first time. After that, the formatter object is available throughout the life of the UNIX process that is running the AMS netlister and is a unique object for that process. The formatter object ID does not change as long as the process remains the same. However, the values of the

fields of the formatter object can change with every netlist run as the netlister rereads the ams.env file.

Running the command

A_formatterId->?

you find that the formatter object contains the fields listed in the next two tables. Some of the fields correspond toams.env variables described in Appendix A, “Variables for ams.env Files.”

Table 13-2 Fields of the Formatter Object

Virtuoso AMS Environment User Guide

Producing Customized Netlists

All of these fields are read-only. Attempting to change their values results in an error.

The formatter object also lists the netlisting procedures that are in effect. The sections of the netlist that each procedure is responsible for generating are listed in the right column. The entries in that column are the same as the labels shown in Figure 13-1 on page 301.

Table 13-3 Netlisting Procedures Listed in the Formatter Object

Virtuoso AMS Environment User Guide

Producing Customized Netlists

Cellview Object

The cellview object contains fields that characterize a cellview.

The cellview object is created when netlisting begins for the cellview and is destroyed when netlisting ends. As a consequence, to view the fields you need to ask for the information during the netlisting run. You might, for example, use statements like the following in your netlisting procedures override file to obtain a list of the fields.

;; Define a print comments functions (defun MyProc (formatter cellview )

(printf "Var = %L\n" cellview->??)

)

Running these statements, you find that the cellview object contains the following fields. Notice that some of these fields return information that is collected indirectly, and is therefore more costly in terms of processing time and memory. For efficient netlisting, try to use such indirectly collected information sparingly.

All of these fields are read-only, so attempting to change their values results in an error.