532
Digital Electronics
Demultiplexer
General Purpose
Registers
Multiplexer
Multiplexer
Arithmetic Logic Unit (ALU)
Status
Register
Stack
Pointer
Program
Counter
Control
Unit
Result
Status
Function
Select
Data Bus
Address Bus
Control Bus
Figure 13.4 Descriptive block diagram of a microprocessor.
13.4.2 Arithmetic Instructions
Arithmetic instructions performed by microprocessors include addition, subtraction, multiplication,
division, comparison, negation, increment and decrement. It may be mentioned here that most of the
eight-bit microprocessors do not support multiplication and division operations. These operations are
supported by the 16-bit and 32-bit microprocessors. The arithmetic operations supported by the 8085
microprocessor are addition, subtraction, increment and decrement operations. Examples are as follows:
ADD R
Adds the contents of the register to the accumulator
ADI eight-bit Adds the eight-bit data to the accumulator
Digital Electronics
Demultiplexer
General Purpose
Registers
Multiplexer
Multiplexer
Arithmetic Logic Unit (ALU)
Status
Register
Stack
Pointer
Program
Counter
Control
Unit
Result
Status
Function
Select
Data Bus
Address Bus
Control Bus
Figure 13.4 Descriptive block diagram of a microprocessor.
13.4.2 Arithmetic Instructions
Arithmetic instructions performed by microprocessors include addition, subtraction, multiplication,
division, comparison, negation, increment and decrement. It may be mentioned here that most of the
eight-bit microprocessors do not support multiplication and division operations. These operations are
supported by the 16-bit and 32-bit microprocessors. The arithmetic operations supported by the 8085
microprocessor are addition, subtraction, increment and decrement operations. Examples are as follows:
ADD R
Adds the contents of the register to the accumulator
ADI eight-bit Adds the eight-bit data to the accumulator