Author name: Abhay

Branch instructions allow the microprocessor to change the sequence of the program, either unconditionally or under certain conditions. Branch instructions are classified into the following three categories. Jump instructions. Call and return instructions. Restart instructions. Jump instructions are classified into two categories: Unconditional and conditional jump instructions. Unconditional Jump Instructions Unconditional jump instructions allow the […]

A microprocessor can perform all the logic functions of the hard-wired logic through its instruction set. These instructions include: AND OR Exclusive-OR Compare Rotate Bits All logic operations are performed in relation to the contents of the accumulator. The complete list of logical instructions in 8085 is described in the following table. Mnemonic Description Example

Arithmetic instructions perform various arithmetic operations such as addition, subtraction, increment, and decrement. Commonly used arithmetic operations are: Add Subtract Increment Decrement The complete list of arithmetic instructions in 8085 is described in the following table. Mnemonic Description Example ADD R 1-byte instructionAdds the contents of register R to the contents of the accumulator. ADD

Data transfer instructions copies data from a source to a destination without modifying the contents of the source. They perform the following six operations: Load an 8 bit number in a register. Copy from register to register. Copy between I/O and accumulator. Load 16-bit number in a register pair. Copy betwwen register and memory. Copy

The entire group of instructions that a microprocessor is called the instruction set of that microprocessor. The instruction set determines what functions the microprocessor can perform. The 8085 instructions are classified into five functional categories Data transfer operations. Arithmetic operations. Logical operations. Branching operations. Machine control operations. Data transfer operations Data transfer instructions copies data