See Also

Boolean expressions consist of operands that are separated by logical and arithmetic operators and comparators, and are optionally grouped within parentheses. Expressions are used in Boolean equations as well as in other statements such as Case and If Then Statements.

A Boolean expression may be one of the following:

• An operand

  Examples: a, b[5..1], 7, VCC

• An in-line logic function reference

  Example: out[15..0] = 16dmux(q[3..0]);

• A prefix operator (! or -) applied to a Boolean expression

  Example: !c

• Two Boolean expressions separated by a binary (non-prefix) operator

  Example: d1 $ d3

• A Boolean expression enclosed in parentheses

  Example: (!foo & bar)

The result of every Boolean expression has the same width as its operands.

You can name Boolean operators and comparators in AHDL files to make it easy to enter resource assignments and to interpret the Equations Section of the Text-Format Report File (.rpt) or HTML-Format Report File (.htm). For more information, go to Naming a Boolean Operator or Comparator.

Back to Top