Program Counter (Pc) - Fujitsu MB90335 Series Hardware Manual

CHAPTER 2 CPU
2.6 Registers
2.6.4

Program Counter (PC)

Program counter (PC) shows lower 16-bit of the memory address of the instruction code
that CPU should execute.
■ Program Counter (PC)
The program counter (PC) register is a 16-bit counter that indicates the lower 16 bits of the memory
address of an instruction code to be executed by the CPU. The upper 8 bits of the address are indicated by
the PCB. The PC register is updated by a conditional branch instruction, subroutine call instruction,
interrupt, or reset. The PC register can also be used as a base pointer for operand access.
Figure 2.6-10 shows the program counter.
PCB
FE
H
36
Figure 2.6-10 Program Counter
PC
ABCD
H
FEABCD
FUJITSU MICROELECTRONICS LIMITED
MB90335 Series
Next instruction to be executed
H
CM44-10137-6E