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/*
 * This is based on the mvme-crt0.S file from libgloss/rs6000.
 * crt0.S -- startup file for PowerPC systems.
 *
 * (c) 1998, Radstone Technology plc.
 *
 *
 * This is an unpublished work the copyright  in  which   vests
 * in  Radstone Technology plc.  All rights reserved.
 *
 * The information contained herein is the property of Radstone
 * Technology  plc.  and  is  supplied  without  liability  for
 * errors or omissions and no part may be reproduced,  used  or
 * disclosed except as authorized by contract or  other written
 * permission.     The    copyright    and    the     foregoing
 * restriction   on  reproduction, use and disclosure extend to
 * all  the   media   in   which   this  information   may   be
 * embodied.
 *
 * Copyright (c) 1995 Cygnus Support
 *
 * The authors hereby grant permission to use, copy, modify, distribute,
 * and license this software and its documentation for any purpose, provided
 * that existing copyright notices are retained in all copies and that this
 * notice is included verbatim in any distributions. No written agreement,
 * license, or royalty fee is required for any of the authorized uses.
 * Modifications to this software may be copyrighted by their authors
 * and need not follow the licensing terms described here, provided that
 * the new terms are clearly indicated on the first page of each file where
 * they apply.
 *
 *  $Id: start.S,v 1.2 2001-09-27 12:00:54 chris Exp $
 */
#include <rtems/score/targopts.h>
#include "ppc-asm.h"
#include "bsp.h"

        .file   "start.s"

        .extern FUNC_NAME(atexit)
        .globl  FUNC_NAME(__atexit)
        .section ".sdata","aw"
        .align  2
FUNC_NAME(__atexit):                    /* tell C's eabi-ctor's we have an atexit function */
        .long   FUNC_NAME(atexit)@fixup /* and that it is to register __do_global_dtors */

        .section ".fixup","aw"
        .align  2
        .long   FUNC_NAME(__atexit)

        .text
        .globl  _start
        .type   _start,@function
_start:
        /* Set MSR */
        /*
         * Enable data and instruction address translation and floating point
         */
        li      r3,MSR_IR | MSR_DR | MSR_FP
        mtmsr   r3

        /*
         * The caches are already flushed by the firmware so just enable
         */
        mfspr   r3,HID0
#if PPC_USE_DATA_CACHE
        /*
         * Enable data and instruction cache
         */
        ori     r3,r3 ,H0_60X_ICE | H0_60X_DCE
#else
        /*
         * Enable instruction cache only
         */
        ori     r3,r3 ,H0_60X_ICE
#endif
        mtspr   HID0,r3
        
        /* clear bss */
        lis     r6,__bss_start@h
        ori     r6,r6,__bss_start@l
        lis     r7,__bss_end@h
        ori     r7,r7,__bss_end@l

        cmplw   1,r6,r7
        bc      4,4,.Lbss_done

        subf    r8,r6,r7                /* number of bytes to zero */
        srwi    r9,r8,2                 /* number of words to zero */
        mtctr   r9
        li      r0,0                    /* zero to clear memory */
        addi    r6,r6,-4                /* adjust so we can use stwu */
.Lbss_loop:
        stwu    r0,4(r6)                /* zero bss */
        bdnz    .Lbss_loop

.Lbss_done:

        /* clear sbss */
        lis     r6,__sbss_start@h
        ori     r6,r6,__sbss_start@l
        lis     r7,__sbss_end@h
        ori     r7,r7,__sbss_end@l

        cmplw   1,r6,r7
        bc      4,4,.Lsbss_done

        subf    r8,r6,r7                /* number of bytes to zero */
        srwi    r9,r8,2                 /* number of words to zero */
        mtctr   r9
        li      r0,0                    /* zero to clear memory */
        addi    r6,r6,-4                /* adjust so we can use stwu */
.Lsbss_loop:
        stwu    r0,4(r6)                /* zero sbss */
        bdnz    .Lsbss_loop

.Lsbss_done:

        lis     sp,__stack@h
        ori     sp,sp,__stack@l

        /* set up initial stack frame */
        addi    sp,sp,-4                /* make sure we don't overwrite debug mem */
        lis     r0,0
        stw     r0,0(sp)                /* clear back chain */
        stwu    sp,-56(sp)              /* push another stack frame */

        li      r3, 0                   /* argc */
        li      r4, 0                   /* argv */
        li      r5, 0                   /* environp */

        /* Let her rip */
        bl      FUNC_NAME(boot_card)

        /*
         * This should never get reached
         */
        /*
         * Return MSR to its reset state
         */
        li      r3,0
        mtmsr   r3
        isync

        /*
         * Call reset entry point
         */
        lis     r3,0xfff0
        ori     r3,r3,0x100
        mtlr    r3
        blr
.Lstart:
        .size   _start,.Lstart-_start