When migrating assembly language programs from one family of microcontrollers to another, the first question is almost always: “What’s the equivalent opcode?” Some operations, like addition and subtraction, are self-evident and practically universal. Other instructions may have some subtle differences in syntax or spelling that make direct conversions a bit trickier. Occasionally, some instructions simply don’t have a direct equivalent in the target set, or an equivalent exists but is explained in different terms. Another question that arises is that of addressing modes. Typically, Direct and Indirect Addressing modes are standard in all architectures. However, they tend to be different in limitations and feature set. AN880 Converting from 8051 to Microchip Assembler: A Quick Reference It is important to remember that this reference list is Author: Gaurang Kavaiya Microchip Technology Inc. only a starting point for code conversion. There are several considerations to keep in mind when moving code from 8-bit 8051 devices to PICmicro devices: 1. The basic processor architecture is significant……