Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/*
 * Copyright (C) Paul Mackerras 1997.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 *
 * NOTE: this code runs in 32 bit mode and is packaged as ELF32.
 */

#include "ppc_asm.h"

        .text
        /* a procedure descriptor used when booting this as a COFF file */
        .globl  _zimage_start_opd
_zimage_start_opd:
        .long   _zimage_start, 0, 0, 0

        .weak   _zimage_start
        .globl  _zimage_start
_zimage_start:
        .globl  _zimage_start_lib
_zimage_start_lib:
        /* Work out the offset between the address we were linked at
           and the address where we're running. */
        bl      1f
1:      mflr    r0
        lis     r9,1b@ha
        addi    r9,r9,1b@l
        subf.   r0,r9,r0
        beq     3f              /* if running at same address as linked */

        /* The .got2 section contains a list of addresses, so add
           the address offset onto each entry. */
        lis     r9,__got2_start@ha
        addi    r9,r9,__got2_start@l
        lis     r8,__got2_end@ha
        addi    r8,r8,__got2_end@l
        subf.   r8,r9,r8
        beq     3f
        srwi.   r8,r8,2
        mtctr   r8
        add     r9,r0,r9
2:      lwz     r8,0(r9)
        add     r8,r8,r0
        stw     r8,0(r9)
        addi    r9,r9,4
        bdnz    2b

        /* Do a cache flush for our text, in case the loader didn't */
3:      lis     r9,_start@ha
        addi    r9,r9,_start@l
        add     r9,r0,r9
        lis     r8,_etext@ha
        addi    r8,r8,_etext@l
        add     r8,r0,r8
4:      dcbf    r0,r9
        icbi    r0,r9
        addi    r9,r9,0x20
        cmplw   cr0,r9,r8
        blt     4b
        sync
        isync

        /* Clear the BSS */
        lis     r9,__bss_start@ha
        addi    r9,r9,__bss_start@l
        add     r9,r0,r9
        lis     r8,_end@ha
        addi    r8,r8,_end@l
        add     r8,r0,r8
        li      r10,0
5:      stw     r10,0(r9)
        addi    r9,r9,4
        cmplw   cr0,r9,r8
        blt     5b

        /* Possibly set up a custom stack */
.weak   _platform_stack_top
        lis     r8,_platform_stack_top@ha
        addi    r8,r8,_platform_stack_top@l
        cmpwi   r8,0
        beq     6f
        add     r8,r0,r8
        lwz     r1,0(r8)
        add     r1,r0,r1
        li      r0,0
        stwu    r0,-16(r1)      /* establish a stack frame */
6:

        /* Call platform_init() */
        bl      platform_init

        /* Call start */
        b       start