Are there any precautions regarding cache control register setting?
Longword access to CCR can be performed from H'FF00 001C in the P4 area and H'1F00 001C in area 7. CCR modifications must only be made by a program in the non-cached P2 area. After CCR is updated, an instruction that performs data access to the P0, P1, P3, or U0 area should be located at least four instructions after the CCR update instruction. Also, a branch instruction to the P0, P1, P3, or U0 area should be located at least eight instructions after the CCR update instruction.