Registers

The Central Processing Unit is a set of registers for storing instructions as well as for
storage and manipulation of temporary result.
Some Registers are given below:

1. Memory Data Register (DR)- Memory Data Register is used to read the value of an operand
from a memory location. It can hold up to 16 bits.

2. Memory Address Register (AR)- Memory Address Register holds the address of memory where
operand is stored. It can hold up to 12 bits.

3. Accumulator - Accumulator is a general purpose processing register. It can hold up to
16 bits.

4. Instruction Register (IR)- IR generally contains 16 bits for storing the instructions.

5. Program Counter (PC)- PC Register generally holds upto 12bits registers and holds the
address of the instruction to be executed next.

6. Temporary Register (TR)- This register can holds upto 8 bits.

7. Stack Pointer (SP)- A stack is created in the main memory and stores information in such
a manner that the item stored last is the first item retrived. The register that holds the
address for the stack is called Stack Pointer.

8. Index Register - Index Register holds upto 16 bit base index register.

9. Flag Register - The Flag Register provides memory information to such information. The
common flag register i.e. overflow, direction, interrupt, sign and zero.