Specifications

A Minimal PowerPCª Boot Sequence for

Executing Compiled C Programs

Source Files

Part V Source Files

The following sections contain the complete source code for the Þles ppcinit.S, ppcinit.h, ld.script, and

makeÞle.

5.1 ppcinit.S

// This file contains generic boot init code designed to be run on

// PowerPC processor simulations that just need minimal setup.

// This code has also successfully been used to run processor-intensive

// benchmarks (written in C) from power-up on minimal hardware boards such as

// Excimer.

// This code is designed to be run from Power-up or hard reset; running from

// soft reset may require additional operations such as cache invalidation,

// that are not supplied here.

// Once the hw init is complete, this code branches into the

// USER_ENTRY defined in the user code

// This code has been tested on the mpc603e, mpc750 and mpc7400/

// Architectural differences between processors with respect to cache

// types and sizes, cache management instructions, number of TLB

// entries, etc, may require changes to be made to this code before it may

// be used successfully on other processors.

// WARNING: If this code is run on a MAX! (MPC7400) processor

// earlier than rev 2.9, certain bits in HID0, IABR, MSSCR0, and

// MSSCR1 have to be set. Please refer to the processor errata if

// problems are encountered with this part.

// NOTE: If you need to define variables, put them at the end! The _start

// symbol needs to be at hreset in order for this code to run automatically

// on hard reset.

#include "ppcinit.h"

.text

.global __eabi

.global _start

.space (0x0100) // locate at hreset vector

// this should now be located at the reset vector

_start:

b system_reset

.space (0x3000) // space past exception space