P1076 February 25, 2016 Meeting Minutes

Attendees:

• Jim Lewis, Peter Flake, Ryan Hinton, Rob Gaddi, Ernst Christen, Jing Pang

Agenda:

Meeting Discussion

• What's Next - see PrivateDocuments file: _summary_vhdl_requirements_priority.xlsx
• Integers
  • Rob tested on GMP and found a 10X increase in run time with arbitrary length integers
    • http://pastebin.com/pHS2yE2X
    • What percentage of simulation time does integer math take up.
  • Ryan some languages play pointer tricks and run near native speed for smaller values
    • Need some tested run times
  • What languages support unbounded integers: python, ruby
  • Not supported by SV or Matlab
  • Need make sure indexing and looping is still fast
    • Maybe keep around a 32 bit object for this?
    • Can compilers already determine this by knowing the objects they are working with?
• 38: Configuration Declaration for Direct Instances
  • Allow to rebind architecture if has been specified in instance vs specify binding only if architecture not specified in instance
  • Want similar capability to component declaration
  • However, have to consider what can we actually do
• 39: Stop Binary, Octal, Hex read before trailing underscore
  • Clarify so that trailing underscore is not read and/or consumed by the read operation
  • Arguments against is the difference between something that is working and something that is correct -
    • It is incorrect to have the '_' separating different values
• 40: OO
  • Lack of justification and not enough time left before we have to be done to consider this
• 41: Bus Mode - part of interface discussion
• 42: Record introspection
  • Without the anonymous types, this is pointless and perhaps impossible
  • Walking field names at run time
  • Need some sort of type identification - ie: array, record, scalar
    • may need on the object interface
    • may need in the run-time of an object
      • name'object_type
  • Have 'basetype 'subtype (spelling?)
  • for i in record_object'field_name loop
    • create implicit enum type having the field_names as values
  • Seems like a good thing, but may be complicated
  • Application:
    • use with anonymous typed subprogram and create a general purpose json/xml writer
  • This would only be useful with run time anonymous types
  • Also comes close to OO
  • Can do some of this sort of thing with VHPI - and write C code.
  • Level of complexity is similar to interfaces and integers and without someone working on it, it will not happen.
• 43: No Overriding Predefined Attributes
  • Ernst: Should not be a language restriction, it should be a coding guidelines restriction
  • Currently a user defined attribute can only be a constant value and never a function call.
  • Alternately, why not extend attributes and give them the capability to return a function value
  • User attributes currently do not pass through levels of hierarchy.
  • What is the utility of that, why not just use function itself
  • AI: Ernst and Cliff coordinate and provide a LCS if one is needed.
  • Currently no reason to make any changes for this item.
• 44: Attributes for PSL
  • Base proposal targeted as testbenches
  • Ryan Extension: PSL Error checking conditions in a synthesizable component. It would be nice to be able to actualize the check as hardware.
  • Is some of this already done for SV?
  • It is also a university topic
  • Ryan wants a 'value that returns a value that can be assigned to a signal (value as a boolean is ok).
    • Can separately convert it to std_logic
    • Checking it in a clocked process
  • Alternately could have an attribute that returns a signal object such that if do a concurrent assignment it will update
  • AI: Ryan provide use case
• 45: Protected Types with Public Signals
  • Likely belongs in the interface bin
  • Rob: if can do interfaces w/o PT in play, then more likely to be accepted.
  • Aspect that does not is protected types need some sort of an event strobe
    • However, this is lighter than a signal - want an event, but do not want to worry about drivers
  • Rob: SharedVar.Method'event or just SharedVar 'event
• restart at 46

Review and Approve Meeting Minutes:

Ryan, Rob

Next Meeting: Thursday March 31, 2016 11 am Pacific

Previous Meeting: Thursday February 18, 2016