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CHAPTER 2 CPU
2.3.4
Program Counter (PC)
This section explains the program counter (PC) functions.
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Program counter (PC)
PC is a 16-bit counter indicating the lower 16 bits in the memory address of an instruction code
to be executed by CPU. An upper 8-bit address is indicated with the program count bank
register (PCB).
instructions, interrupts, or resets. It may also be used as a base pointer for operand access.
Figure 2.3-10 explains the program counter (PC) functions.
PCB
FE
H
36
PC contents are updated by condition branch instructions, subroutine call
Figure 2.3-10 Program counter (PC) functions
PC
ABCD
H
Next instruction executed
FEABCD
H
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