An Instruction Set and Addressing Modes

Abstract

The instruction set of a CPU is a list of the instructions available to the user of that CPU. A comprehensive guide to the instruction set of any CPU details the effect of every instruction not only on the internal registers of the CPU, but also on the external elements of the microcomputer. It also describes the time taken to fetch and execute every instruction in terms of the number of clock pulses of the master oscillator. Since a detailed description of the instruction set will take up a very large number of pages, the description of instructions in this section is limited to that which is necessary for the reader to appreciate the primary effects of the instructions. A comprehensive description of the 8085 instruction set is given in appendix A and appendix B.