P1076 January 31, 2013 Meeting Minutes



  • Review VHDL-2008-Performance remaining list items
  • Review VHDL-2008-MP remaining list items
  • Review Accellera TC remaining list items
  • See these items in the collected requirements list


  • Peter met with SCE-MI
    • For dual languages, they want a DPI to SystemVerilog Data Types
    • Wanted to know time line for it to ge in the standard
  • DPI to ADA?

64 bit Integers and Beyond, and Real

  • Extend integer to full 2's complement range
  • Need bigger integers for coverage modeling and randomization
  • Separate type or subtypes?
  • integer subtypes & subprogram elaboration will need to be considered
  • Need someone to start a proposal page and flow above into this
  • What does Ada do?

Performance Proposals

  • Perf 1: lots of concern about removal of delta cycles
    • NN much performance gain
    • reject
  • Perf 2: Expressions in sensitivity lists (posedge)
    • Isn't a compiler smart enough to extract this anyway - especially if it can handle process (all).
    • reject
  • Perf 3: 2 & 4 state semantics
    • Simulate std_logic using 2 states (0, 1) or 4 states (0,1,X,Z)
    • Could this buy us anything?
    • Where would it be specified to do this? Is it a tool thing?
    • Does bit simulate faster / use less memory that std_logic?
    • Why can't a compiler/simulator do this automatically for RTL code?
      • If I cannot do it, can I mark it somehow?
      • Simulator flag or marker in code?
    • Further Action Required
  • Perf 4: Light-weight signals
    • Should be handled as a simulator optimization!
    • Is this shared variable with regular types?
    • Does it have a delta cycle?
    • Need to have a use model that interests us
    • reject
  • Perf 5: Atomic Composite Signals
    • Normal composites track events on each subelement
    • Atomic composite only tracks events on the composite
    • With Atomic do I get element resolution functions or do require a resolution function for the entire composite?
    • Can simulators already do this?
      • To some degree. If elements not accessed
    • Are there use cases that the compiler needs help with?
      • What sort of help does the compiler need?
      • Will this provide any benefit?

Action Items:

  • none

Review and Approve Meeting Minutes:

  • Motion: Cliff 2nd: Peter

Next Meeting Date (proposed):

Thursday February 21, 8 am Pacific

Topic revision: r4 - 2020-02-17 - 15:36:12 - JimLewis
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