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path: root/src/arch/ppc/lib/c_start.S
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/* Copyright 2000  AG Electronics Ltd. */
/* This code is distributed without warranty under the GPL v2 (see COPYING) */

/*
 * The assumption is that we're located in ROM and we have a fake stack
 * located in cache. Our task is to turn on memory proper, the finish
 * configuring the machine.
 */

#define ASM
#include "ppcreg.h"
#include <ppc_asm.tmpl>

.section ".text"
.globl _start

_start:
	/* 
	 * init stack pointer to real ram now that memory is on
	 */
	lis     r1, _estack@ha
	addi    r1, r1, _estack@l
	stwu    r0,-64(r1) 
	stwu    r1,-24(r1) 

	/*
	 * Clear stack
	 */
	lis	r4, _stack@ha
	addi	r4, r4, _stack@l
	lis	r7, _estack@ha
	addi	r7, r7, _estack@l
	lis	r5, 0
1:	stwx	r5, 0, r4
	addi	r4, r4, 4
	cmp	0, 0, r4, r7
	ble	1b
	sync

	/*
	 * Clear bss
	 */
	lis	r4, _bss@ha
	addi	r4, r4, _bss@l
	lis	r7, _ebss@ha
	addi	r7, r7, _ebss@l
	lis	r5, 0
1:	stwx	r5, 0, r4
	addi	r4, r4, 4
	cmp	0, 0, r4, r7
	ble	1b
	sync

	/*
	 * Set up the EABI pointers, before we enter any C code
	 */
	lis     r13, _SDA_BASE_@ha
	addi    r13, r13, _SDA_BASE_@l
	lis     r2, _SDA2_BASE_@ha
	addi    r2, r2, _SDA2_BASE_@l

	/*
	 * load start address into SRR0 for rfi
	 */
	lis	r3, hardwaremain@ha
	addi	r3, r3, hardwaremain@l
	mtspr	SRR0, r3

	/*
	 * load the current MSR into SRR1 so that it will be copied 
	 * back into MSR on rfi
	 */
	mfmsr	r4
	mtspr	SRR1, r4	// load SRR1 with r4

	/*
	 * If something returns after rfi then die
	 */
	lis	r3, dead@ha
	addi	r3, r3, dead@l
	mtlr	r3

	/*
	 * Complete rest of initialization in C (hardwaremain)
	 */
	rfi

	/*
	 * Stop here if something goes wrong
	 */
dead:
	b	dead
	/*NOTREACHED*/

/* Remove need for ecrti.o and ectrn.o */
.globl __init
__init:
.globl __fini
__fini:
.globl __CTOR_LIST__
__CTOR_LIST__:
.globl __CTOR_END__
__CTOR_END__:
.globl __DTOR_LIST__
__DTOR_LIST__:
.globl __DTOR_END__
__DTOR_END__:
        blr