- 6 general purpose registers to store 8-bit data B, C, D, E, H & L.
- Can be combined as register pairs – BC, DE, and HL to perform 16-bit operations.
- Used to store or copy data using data copy instructions.
Accumulator
- 8 - bit register, identified as A
- Part of ALU
- Used to store 8-bit data to perform arithmetic & logical operations.
- Result of operation is stored in it.
Flag Register
- ALU has 5 Flag Register that set/reset after an operation according to data conditions of the result in accumulator & other registers.
- Helpful in decision making process of Microprocessor
- Conditions are tested through software instructions
- For e.g.
- JC (Jump on Carry) is implemented to change the sequence of program when CY is set.
Program Counter
- 16-bit registers used to hold memory addresses.
- Size is 16-bits because memory addresses are of 16-bits.
- Microprocessor uses PC register to sequence the execution of instructions.
- Its function is to point to memory address from which next byte is to be fetched.
- When a byte is being fetched, PC is incremented by 1 to point to next memory location.
Stack Pointer
- Used as memory pointer
- Points to the memory location in R/W memory, called Stack.
- Beginning of stack is defined by loading a 16-bit address in the stack pointer.