Parallel versus serial execution

• assign statements are implicitly parallel

  • “=” means continuous assignment
  • Example  assign E = A & D; assign A = B & C;
  • A and E change if B changes

• always blocks execute in parallel

  • always @(posedge clock)

• Procedural block internals not necessarily parallel

  • “=” is a blocking assignment (sequential)
  • “<=” is a nonblocking assignment (parallel)
  • Examples of procedures: always, function, etc.

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