Get the information stored in the CPU registers based on the current thread of the process associated with the file descriptor. The argument is a pointer to a procfs_greg structure (see debug_greg_t in <sys/debug.h>) that's filled in with the required information on return. If you provide a non-NULL extra argument, it's filled with the size of the data. For example:

procfs_greg my_greg;

devctl( fd, DCMD_PROC_GETGREG, my_greg, sizeof(procfs_greg),

To set the CPU registers, use DCMD_PROC_SETGREG .