Instruction Set Summary Source: http://www.edsim51.com/8051Notes/8051/instructionSetSummary.html under http://www.edsim51.com/8051Notes/index.html
Instructions tell the processor which operation to carry out Instructions tell the processor which operation to carry out. For example, MOV A, #5EH tells the processor to move the data 5EH to the accumulator.
Instructions result in the processor performing some operation on some data (the data being #5EH in the example above). The instruction above is an example of what's known as immediate addressing. The reason for this is because the data immediately follows the instruction in code memory.
Address Modes Immediate Register Direct Indirect Relative Absolute Long Indexed