Application processors

So far we've talked about microcontrollers, such as the Arm Cortex-M series. Now let's try writing something for Cortex-A. For simplicity we'll just work with QEMU's aarch64 'virt' board.

  • Broadly speaking, microcontrollers don't have an MMU or multiple levels of privilege (exception levels on Arm CPUs, rings on x86), while application processors do.
  • QEMU supports emulating various different machines or board models for each architecture. The 'virt' board doesn't correspond to any particular real hardware, but is designed purely for virtual machines.