Miscellaneous instructions ========================== * nop() ``pass`` no operation. * wfi() Suspend execution in a low power state until an interrupt occurs. * cpsid(flags) set the Priority Mask Register - disable interrupts. * cpsie(flags) clear the Priority Mask Register - enable interrupts. * mrs(Rd, special_reg) ``Rd = special_reg`` copy a special register to a general register. The special register may be IPSR (Interrupt Status Register) or BASEPRI (Base Priority Register). The IPSR provides a means of determining the exception number of an interrupt being processed. It contains zero if no interrupt is being processed. Currently the ``cpsie()`` and ``cpsid()`` functions are partially implemented. They require but ignore the flags argument and serve as a means of enabling and disabling interrupts.