## Predefined Evaluated Functions

The following predefined evaluated functions are built into AHDL; that is, no Define Statements are needed to use them:

The `USED`

function can be used to test whether a port has been used, for example, in an If Generate Statement or a Parameters Statement. `USED`

takes the port name as input and returns a value of `FALSE`

if the port is not used.

The `CEIL`

function specifies the ceiling of a real number, which is the smallest integer
that is equal to or greater than the real number. Although this operation applies to all
arithmetic expressions, it is meaningful only for `LOG2`

and `DIV`

operations
in which the result can be a real number.

- The
`FLOOR`

function specifies the floor of a real number, which is the largest integer that is equal to or less than the real number. Although this operation applies to all arithmetic expressions,
it is meaningful only for `LOG2`

and `DIV`

operations in which the result can
be a real number.

Example

You can use these predefined evaluated functions in arithmetic expressions only; you cannot use evaluated functions in Boolean expressions.

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