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#
# Copyright (C) 2005 Jakub Jermar
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
# - Redistributions of source code must retain the above copyright
#   notice, this list of conditions and the following disclaimer.
# - Redistributions in binary form must reproduce the above copyright
#   notice, this list of conditions and the following disclaimer in the
#   documentation and/or other materials provided with the distribution.
# - The name of the author may not be used to endorse or promote products
#   derived from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#

#include <arch/boot/boot.h>

.register %g2, #scratch
.register %g3, #scratch
.register %g6, #scratch
.register %g7, #scratch

.section K_TEXT_START, "ax"

/*
 * Here is where the kernel is passed control.
 * The code must be position independent until
 * the kernel relocates itself to its VMA.
 */

.global kernel_image_start
kernel_image_start:
0:
    b 1f
    nop

/*
 * This header forces SILO to load the kernel at 0x4000.
 * More precisely, SILO will think this is an old version of Linux.
 */
.ascii "HdrS"
.word 0
.half 0

.align 8

1:
    flushw              ! flush all but the active register window

    /*
     * Prepare to copy the kernel image to 4M.
     */

    set LMA, %g1            ! source address
    set VMA, %g2            ! destination address
    set hardcoded_ktext_size, %g3   ! link address of hardcoded_ktext_size
    set hardcoded_kdata_size, %g4   ! link address of hardcoded_kdata_size

    sub %g3, %g2, %g3       ! offset of hardcoded_ktext_size from the beginning of the load address
    sub %g4, %g2, %g4       ! offset of hardcoded_kdata_size from the beginning of the load address
    
    ldx [%g3 + %g1], %g3        ! hardcoded_ktext_size -> %g3
    ldx [%g4 + %g1], %g4        ! hardcoded_kdata_size -> %g4

    add %g3, %g4, %g3       ! size of kernel text and data

    /*
     * Start copying the kernel from higher addresses towards lower addresses.
     */

2:  dec %g3
    ldub [%g1 + %g3], %g4
    stb %g4, [%g2 + %g3]
    cmp %g3, 0
    bnz 2b
    nop

    set relocated, %g1
    jmp %g1
    nop

relocated:
    set ofw, %l0

    call ofw_init
    stx %o4, [%l0]

    call main_bsp
    nop

    /* Not reached. */

2:
    b 2b
    nop