Hi Dave,
Can you help with difference between semaphore and event. If both are used for synchronization purpose then where to use what? Please help
In reply to kranthi445:
An named event in SystemVerilog is broadcasting signal without a value. Think of a clock as broadcasting signal in hardware where everyone is looking for the rising edge (@posedge clock) as its event. But you have to go through the process of setting the clock to 0 for some period, and then setting it 1 for some period to get the posedge event.
A named event just requires an instantaneous trigger (->name or ->>name) to signal all the other processes waiting for @name. Since your testbench should be written without timing, you would use an event instead of ever waiting for the rising/falling edge of a signal within your testbench.
A semaphore is a locking mechanism using a set of keys to a shared resource that processes us the get() and put() methods to manage the keys. The shared resource might be to write to a variable or access to a bus.
Both of these constructs are fairly low-level, and the UVM has many higher level constructs for synchronization. So I suggest you avoid them until you have exhausted other possible solutions.
BTW, I happy to answer questions when I have the time, but please don’t directly address them to me so other people have the opportunity :)