Most operations require two operands. One of these operands usually comes from memory via the memory buffer register , while the other is the previously loaded value stored in the accumulator . The results of an arithmetic-logic unit operation is usually transfered to the accumulator . The basic components found on the central processing unit include the accumulator , arithmetic-logic unit , control unit , instruction register , memory address register , memory buffer register and the program counter . Clock Pulse A circuit which sends pulses of current to the central processing unit.
Nothing happens in the computer untill a pulse is received.
This is accomplished by using the contents of the instruction register to decide which circuits are to be activated. A register located on the central processing unit which holds the contents of the last instruction fetched. This instruction is now ready to be executed and is accessed by the control unit . These individual bits are grouped together in lots of eight and are referred to as a byte. Every byte in memory can be accessed by a unique address which identifies its location.