program counter


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Related to program counter: Instruction register, Memory address register

program counter

[′prō·grəm ‚kau̇nt·ər]
(computer science)

program counter

(hardware)
(PC, or "instruction address register") A register in the central processing unit that contains the addresss of the next instruction to be executed. The PC is automatically incremented after each instruction is fetched to point to the following instruction. It is not normally manipulated like an ordinary register but instead, special instructions are provided to alter the flow of control by writing a new value to the PC, e.g. JUMP, CALL, RTS.

program counter

A register in the control unit of the CPU that is used to keep track of the address of the current or next instruction. Typically, the program counter is advanced to the next instruction, and then the current instruction is executed. Also known as a "sequence control register" and the "instruction pointer." See address register and instruction register.
References in periodicals archive ?
When the macro_end instruction is executed, the program counter is reset to the top value of the program counter stack (which is popped), and execution continues at the next instruction.
We previously noted (May 1991) the Bank of New York's accidental $32 billion overdraft due to an unchecked program counter over-flow, with BoNY having to fork out $5 million for a day's interest (SEN 11, 1, 1986, 3-7).
In its simplest form a power log window displays the measured current and the time and location of the program counter when it was sampled.
The '400 includes a 24-bit program counter, four 24-bit data pointers, a 10-bit stack pointer and special function register (SFR) bits to control the expanded-addressing operations.
There are nine addressing modes, permitting memory addresses to be computed from most of the useful combinations of the program counter, register contents and/or a displacement of 12, 16, or 32 bits.
A simple procedure-time profiler estimates the time spent in each procedure by observing the program counter at a regular interval (60 times a second on my system).

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