Chapter 9

Foundation Express Directives

The Foundation Express HDL compiler has several methods of writing circuit design information directly in your VHDL source code.

Using Foundation Express directives, you can direct the translation from VHDL to components with special VHDL comments. These synthetic comments turn translation on or off, specify one of several hard-wired resolution methods, and provide a means to map subprograms to hardware components.

To familiarize yourself with Foundation Express directives, consider the following topics presented in this chapter.

•“Notation for Foundation Express Directives”

•“Foundation Express Directives”

Notation for Foundation Express Directives

Foundation Express directives are special (synthetic) VHDL comments that affect the actions of Foundation Express. These comments are a special case of regular VHDL comments, which are ignored by other VHDL tools. Synthetic comments are used only to direct the actions of Foundation Express.

Synthetic comments begin with two hyphens (--) like a regular comment. If the word following these characters is pragma or synopsys, Foundation Express treats the remaining comment text as a directive.

Note: Foundation Express displays a syntax error if an unrecognized directive is encountered after -- synopsys or -- pragma.