Program counter

The program counter is a processor register that holds the address of the next instruction to execute. Control-flow instructions can change that address, redirecting execution.

Instruction cycle: The repeated process by which a processor fetches, decodes, and executes instructions. The program counter supplies the address used during each instruction fetch.
Machine code: The binary instructions directly interpreted or executed by a processor. The program counter addresses positions in the instruction stream encoded as machine code.
Stack pointer: A processor register that identifies the current position of a program's stack. It tracks stack data, while the program counter tracks instruction position.
Debugger: A tool for inspecting and controlling a program's execution state. Debuggers display or modify the instruction address to pause or redirect execution.
Instruction pointer: A processor register that identifies the instruction address used by the execution sequence. This is the common x86 name for a register serving the program-counter role.
Memory address: A value identifying a location in a computer's addressable memory. The counter stores an address rather than the instruction's contents.
Frame pointer: A register or convention identifying a stable reference point in a function's stack frame. It helps locate function data rather than determine which instruction executes next.
Context switch: An operating-system operation that saves one execution context and restores another. Saving and restoring the program counter lets a task resume where it stopped.
Branch instruction: An instruction that changes execution to a specified or computed program address. A branch replaces the sequential address the program counter would otherwise hold.
Instruction set architecture: The programmer-visible specification of a processor's instructions, registers, and execution behavior. An architecture defines the program counter's visible behavior and conventions.

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