upd70f3017ay Renesas Electronics Corporation., upd70f3017ay Datasheet - Page 68

• Manufacturer Part Number: upd70f3017ay
• Description: V850/sa1tm 32-/16-bit Single-chip Microcontroller
• Manufacturer: Renesas Electronics Corporation.

3.4.3 Wraparound of CPU address space
(1) Program space
(2) Data space
68
Of the 32 bits of the PC (program counter), the higher 8 bits are fixed to 0, and only the lower 24 bits are valid.
Even if a carry or borrow occurs from bit 23 to bit 24 as a result of branch address calculation, the higher 8 bits
ignore the carry or borrow and remain 0. Therefore, the lower-limit address of the program space, address
00000000H, and the upper-limit address 00FFFFFFH are contiguous addresses, and the program space is
wrapped around at the boundary of these addresses.
The result of operand address calculation that exceeds 32 bits is ignored. Therefore, the lower-limit address of
the program space, address 00000000H, and the upper-limit address FFFFFFFFH are contiguous addresses,
and the data space is wrapped around at the boundary of these addresses.
Caution No instruction can be fetched from the 4 KB area of 00FFF000H to 00FFFFFFH because this
area is defined as peripheral I/O area. Therefore, do not execute any branch operation
instructions in which the destination address will reside in any part of this area.
00FFFFFEH
FFFFFFFEH
00FFFFFFH
FFFFFFFFH
00000000H
00000001H
00000000H
00000001H
Program space
Program space
Data space
Data space
CHAPTER 3 CPU FUNCTIONS
Figure 3-4. Program Space
User’s Manual U12768EJ4V1UD
Figure 3-5. Data Space
(+) direction
(+) direction
(–) direction
(–) direction