CHAPTER 3 CPU FUNCTIONSUser’s Manual U16896EJ2V0UD 513.4.2 Wraparound of CPU address space(1) Program spaceOf the 32 bits of the program counter (PC), the higher 6 bits are fixed to 0 and only the lower 26 bits are valid.Even if a carry or borrow occurs from bit 25 to bit 26 as a result of branch address calculation, the higher 6 bitsignore this and remain 0.Therefore, the lower-limit address of the program space, 00000000H, and the upper-limit address,03FFFFFFH, are contiguous addresses, and the program space is wrapped around at the boundary of theseaddresses.Caution No instructions can be fetched from the 4 KB area of 03FFF000H to 03FFFFFFH because thisarea is an on-chip peripheral I/O area. Therefore, do not execute any branch operationinstructions in which the destination address will reside in any part of this area.03FFFFFEH03FFFFFFH00000000H00000001H Program spaceProgram space(+) direction (–) direction(2) Data spaceThe result of an operand address calculation that exceeds 32 bits is ignored.Therefore, the lower-limit address of the data space, address 00000000H, and the upper-limit address,FFFFFFFFH, are contiguous addresses, and the data space is wrapped around at the boundary of theseaddresses.FFFFFFFEHFFFFFFFFH00000000H00000001H Data spaceData space(+) direction (–) direction
