2 Introduction

This guide highlights the source code and build changes that might be required should you decided to migrate a project from the Microchip MPASM™ assembler (MPASM) to the MPLAB® XC8 PIC Assembler (PIC Assembler).

The majority of the changes required when migrating a project will be to assembler directives. Instruction sequences typically do not require alteration, although some instruction operand expressions might require the use of different operators or syntax.

A migrated project will almost certainly produce a hex file that differs to one produced from the original MPASM project built with the MPASM assembler. When building with the PIC Assembler, objects and code might be linked at different addresses, meaning that different address operands will be used with instructions, and different bank and page selection sequences might be present. Instruction sequences, however, should remain unchanged, as no optimizations or code transformations are performed by the PIC Assembler.

You can use the PIC Assembler from within the MPLAB X IDE. Projects dedicated to this tool can be created and will use their own set of options displayed in the project's properties.

See the MPLAB® XC8 PIC Assembler User's Guide for full information on how to use the assembler and for more detailed information on the assembler's directives and language. A separate MPLAB® XC8 PIC Assembler Guide for Embedded Engineers document contains code and build option examples and getting started information.