IEEE 200X Fast Track Change Proposal

ID:      FT-30

Status:       Proposed
Proposed:     29 March 2005
Analyzed:     Date
Resolved:     Date

Related issues:  
Relevant LRM sections:   



Enhancement/Requirements:
-------------------------------------------------------- 
Roll-up of changes made to standard packages not covered elsewhere.

1.  Define function for implementation-defined new line string, eg:

      impure function NL return STRING;

    It has been suggested that this might be declared in package
    STANDARD, but it might be more appropriate to declare it in
    TEXTIO.

    The name is potentially problematic.  It could clash with a
    user-declared identifier.  It may be apppropriate to name the
    function NEWLINE to reduce the chance of name clash.

2.  Define a function to query the simulator resolution, eg:

      impure function SIM_RESOLUTION return DELAY_LENGTH;

    An appropriate place to declare this function would be in the
    package ENV introduced in FT13.  The function might alternatively
    be named RESOLUTION_LIMIT, since that is the term defined in the
    LRM for resolution of time values during execution.

3.  Define functions to detect rising and falling edges of BOOLEAN and
    BIT signals, eg:

      function RISING_EDGE  (signal S: BOOLEAN) return BOOLEAN;
      function FALLING_EDGE (signal S: BOOLEAN) return BOOLEAN;

      function RISING_EDGE  (signal S: BIT) return BOOLEAN;
      function FALLING_EDGE (signal S: BIT) return BOOLEAN;

    The functions would be defined in package STANDARD, and would
    perform operations equivalent to the following bodies:

      function RISING_EDGE (signal S: BOOLEAN) return BOOLEAN is
      begin
          return S'EVENT and S;
      end;

      function FALLING_EDGE (signal S: BOOLEAN) return BOOLEAN is
      begin
          return S'EVENT and not S;
      end;

      function RISING_EDGE (signal S: BIT) return BOOLEAN is
      begin
          return S'EVENT and S = '1';
      end;

      function FALLING_EDGE (signal S: BIT) return BOOLEAN is
      begin
          return S'EVENT and S = '0';
      end;

    Provision of these functions would allow synthesizable code for
    BOOLEAN and BIT values to mirror code for STD_LOGIC values in
    form, making it easier to manage changes in data-type
    representation.


Analysis/LRM Changes
----------------------------
[To be performed by the 200X Fast Track Working Group]


Resolution:
----------------------------
[To be performed by the 200X Fast Track Working Group]