Using pseudo instructions to invoke a method of a simobject

[kaplannp]

Hi all. Gem5 beginner here. I'm trying to hack the simulator to add a new SimObject and invoke one of its methods through a pseudo instruction.

I've registered my pseudo instruction in these files

include/gem5/m5ops.h
include/gem5/asm/generic/m5ops.h
util/m5/src/command/[INSTRUCTION].cc 

Then I add the line tc->getSystemPtr()->MySimObject->myMethod() to a new pseudo instruction in src/sim/pseudo_inst.cc, but when I go to compile I get the error
src/sim/pseudo_inst.cc:568:30: error: ‘class gem5::System’ has no member named MySimObject

Is this the right way to go about this? Where can I instantiate MySimObject so it will be available to me in the pseudo instruction?

[robhau]

Hi @kaplannp,

I would propose you another design to to achieve your desired behavior.

Usually, you can configure peripherals (I assume that your SimObject is a peripheral) by writing to memory mapped registers. They are also used to trigger specific tasks. So I suggest that you implement register(s) in your SimObject that corresponds to your task(s). When write, for example, a 1 to a task register, you then call your member function.

Gem5 already offers you register banks that you can use to implement registers (see src/dev/reg_bank.hh). Take a look in SimObjects where they are used to learn how they work. For example, they are part of Plic and Clint (src/dev/riscv/*)