P1076 January 31, 2013 Meeting Minutes

Attendees:

• CliffordWalinsky * PeterFlake * JarekKaczynski * JimLewis

Agenda:

• 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

DPI & SCE-MI

• 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