When you first try to issue floating point instructions on the processor, you may run into a “Device Not Found” exception. This is because the Pintos starter code intializes the CR0 register to indicate that there is no FPU by setting the
CR0_EM bit. You must update this in
threads/start.S to remove the flag and indicate to the processor that the FPU is present.
- orl $CR0_PE | CR0_PG | CR0_WP | CR0_EM, %eax + orl $CR0_PE | CR0_PG | CR0_WP, %eax