2. E.U unit performs the following functions.
It performs the logic and Arithmetic
operation on memory or register.
It receives the instruction from pre fetch
queue and decodes it.
It stores the information temporary in the
register array.
3. Control Circuit
ALU
General Purpose Register
Special Purpose Register
2 pointer registers
2 index registers
6. This is a 16 bit unit which performs
the AND, OR, Exclusive, Addition,
Subtraction, Increment, Decrement,
Complement and Shift functions.
7.
8. It has 4 data registers,AX, BX, CX,
DX
AX, BX, CX and DX registers has 2 8-
bit registers to access the high and
low byte data registers.The high
byte of AX is called AH and the low
byte is AL. Similarly,
9.
10. Flags Register
It is also called status register
flags represent result of last
arithmetic or logical instruction
executed. Conditional flags are as
follows:
1. CF (Carry Flag)
2. AF (Auxiliary Flag)
3. PF (Parity Flag)
4. ZF (Zero Flag)
11. Flags Register
5. SF (Sign Flag)
6. OF (Overflow Flag)
Control register
5. TF (Trap Flag):
6. IF (Interrupt Flag):
7. DF (Direction Flag):
And Seven undefined flags register
12. 2 pointer registers SP, BP
SP (Stack pointer)
BP (Base pointer)
2 index registers SI, DI
SI(Sours index)
DI (Destination index)
