Code segment (CS) is a 16-bit register containing address of 64 KB segment with processor instructions. The processor uses CS segment for all accesses to instructions referenced by instruction pointer (IP) register. CS register cannot be changed directly. The CS register is automatically updated during far jump, far call and far return instructions.
In computer architecture, a processor register is a quickly accessible location available to a computer’s central processing unit (CPU). Registers usually consist of a small amount of fast storage, although some registers have specific hardware functions, and may be read-only or write-only. Registers are normally measured by the number of bits they can hold, for example, an “8-bit register”, “32-bit register” or a “64-bit register” (or even with more bits).
The Intel 8086, also called the iAPX 86, is a 16-bit microprocessor designed by Intel corporation between 1976-1978. This Intel 8086 microprocessor gave rise to the x86 architecture or 16-bit architecture. The figure given below is the internal architecture of Intel 8086 microprocessor