Using XSIM

In this section, we have a series of examples which show some ways of using XSIM to gain a greater insight into how programs run on XCORE devices.

Which tile is my code running on?

Build and execute the example in Targeting multiple tiles:

$ xcc -target=XCORE-200-EXPLORER multitile.xc main.c
$ xrun --io a.xe
Hello from tile 0
Hello from tile 1

How can we convince ourselves that the output was generated by code running on the specified tiles? We can use xsim -t to determine which tile the system calls were generated by. Here we use grep to simplify and reduce the trace output by capturing 1 line before each of the relevant output lines:

$ xsim -t a.xe | grep -B 1 "Hello from"
tile[0]@0- -SI A-.----00040264 (_DoSyscall          +  0) : nop      @11057
Hello from tile 0
tile[1]@0- -SI A-.----00040234 (_DoSyscall          +  0) : nop      @11061
Hello from tile 1

This shows that the system calls were generated by the expected tiles.

Using XScope during simulation

You can use XScope when running code on the simulator. It isn’t faster than the non-Xscope approach, but it allows debug of any XScope-related issues.

Build the example in Using XSCOPE for fast “printf debugging”. Execute the application using the xsim --xscope option as follows:

$ xsim --xscope "-offline xscope.vcd" a.xe
Tile 0: Result 0
Tile 1: Iteration 0 Accumulation: 0
Tile 1: Iteration 1 Accumulation: 1
Tile 1: Iteration 2 Accumulation: 3
Tile 1: Iteration 3 Accumulation: 6
Tile 1: Iteration 4 Accumulation: 10
Tile 1: Iteration 5 Accumulation: 15
Tile 1: Iteration 6 Accumulation: 21
Tile 1: Iteration 7 Accumulation: 28
Tile 1: Iteration 8 Accumulation: 36
Tile 1: Iteration 9 Accumulation: 45
Tile 0: Result 45

XScope trace output will be placed in xscope.vcd.