Basic execution control¶
Renode allows you to precisely control the execution of the emulation.
Starting and pausing the execution¶
At the beginning emulation is in paused state which means that no machine is running and virtual time is not progressing.
To start the emulation execute:
(machine-0) start Starting emulation...
To pause it type:
(machine-0) pause Pausing emulation...
When you need to analyze in details how the execution of your binary influences the state of a hardware you can switch to stepping execution mode:
(machine-0) sysbus.cpu ExecutionMode SingleStepBlocking
This will stop the emulation after execution of each instruction. In order to move to the next one type:
(machine-0) sysbus.cpu Step
When you want to return to the normal execution mode type:
(machine-0) sysbus.cpu ExecutionMode Continuous
More advance control can be obtained by connecting external GDB.
Blocking and non-blocking stepping¶
When you use
SingleStepBlocking mode the emulation won’t progress between steps.
This can cause problems with blocking the emulation when executing multiple cores instruction-by-instruction, in which case
SingleStepNonBlocking mode is the preferred option.
The drawback of the non-blocking mode is that the virtual time will progress between steps, which might introduce desynchronization and timeout-related issues.
Step command will preserve the current mode when in instruction-by-instruction flow and use the default value (
This behavior can be overridden by selecting the non-blocking mode explicitly:
(machine-0) sysbus.cpu Step false
Inspecting current location¶
Renode allows you to easily examine the current state of your application:
(machine-0) sysbus.cpu PC 0xC01890A8
As a result you will get a hexadecimal address of the instruction currently executed.
If you want to know the name of the function that is currently executed (assuming your binary has been compiled with the symbols inside) type:
(machine-0) sysbus FindSymbolAt `sysbus.cpu PC` # equivalent of 0xC01890A8 uart_console_write
This will print the name of the symbol.