VHDLViewportDirective < P1735

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*24.1.2.23 Protect viewport directive*

protect_viewport_directive :: =
*` protect viewport* = ( viewport_object_description , viewport_access_description )

viewport_object_description ::= *object* = string_literal

viewport_access_description ::= *access* = string_literal

A protect viewport directive describes a declared object or objects in a VHDL description for which certain
operations are to be permitted by a tool.

The value of the string literal following the object keyword identifies the declared object or objects. The
value shall be in the form of the <nop>DefName property (see 19.4.6) of a VHPI object representing a declared
object, but with the leading commercial at character, library name and period omitted. The declared objects
identified are those declared objects for which both of the following hold:
   * The declared object is declared in the source text of the protection envelope containing the protect viewport directive.
   * The <nop>DefName property of the VHPI object representing the declared object, with the leading commercial at character, library name and period omitted, is the same as the value of the string literal, not counting differences in the use of corresponding uppercase and lowercase letters in basic identifiers.

If more than one declared object is identified, the operations are to be permitted for all of those declared
objects.

The string literal following the access keyword specifies which operations are permitted for the identified
declared object or objects, as follows:

   *  "R": _Read-only access_ The object may be read by any part of the VHDL description, by a VHPI program, or by a tool. It is an error if the object is updated other than by part of the VHDL description contained within the protection envelope containing the protect viewport directive.
   * "W": _Write-only access_ The object may be updated by any part of the VHDL description, by a VHPI program, or by a tool. It is an error if the object is read other than by part of the VHDL description contained within the protection envelope containing the protect viewport directive.
   * "RW": _Read-write access_ The object may be read and updated.
Topic revision: r1 - 2010-07-23 - 16:05:04 - JohnShields
P1735