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This document describes the procedures necessary to initialize a PowerPC™ processor
successfully and begin executing programs compiled using the embedded PowerPC
application interface (EABI). The items discussed in this document have been tested for
MPC603e™, MPC750, and MPC7400 microprocessors. The methods and source code
presented in this document may work unmodified on similar devices as well.
This document contains the following topics:
• Part I, “Overview,” provides a summary of the conditions and exceptions for the
procedures described in this document.
• Part II, “Processor Initialization,” provides information on the general setup of the
processor registers, caches, and MMU.
• Part III, “EABI Compliance,” discusses aspects of the EABI that apply directly to
preparing to jump into a compiled C program.
• Part IV, “Sample Boot Sequence,” describes the basic operation of the boot sequence
and the many options of configuration, explains in detail a sample configurable boot
and how the code may be modified for use in different environments, and discusses
the compilation procedure using the supporting GNU build environment.
• Part V, “Source Files,” contains the complete source code for the files ppcinit.S,
ppcinit.h, reg_defs.h, ld.script, and Makefile.
• Part VI, “Revision History,” contains a table that lists the document revisions since its
inception.
Part I Overview
The procedures discussed in this document perform only the minimum amount of work
necessary to execute a user program. The sample boot sequence is designed to run from
system reset. It does not contain exception handling facilities for other exceptions, although
the code is located so that it doesn’t interfere with exception space. This allows users who wish
to provide exception handling to add exception code without modifying this source. In
addition, this code only handles processor setup. It does not initialize any peripheral devices
because it is designed to be run on instruction set simulators, test cards, or small evaluation
boards. No input/output interface is provided. Results are obtained by looking at data saved in
memory via hardware debuggers or simulator commands.
Application Note
AN1809
Rev. 1.2, 11/2003
Minimal Boot Sequence
for Executing Compiled C
Programs on PowerPC™
Devices
Freescale Semiconductor, I
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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