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#
# Copyright (C) 2005 Jakub Jermar
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#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
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#include <arch/asm/regname.h>
#include <arch/asm/spr.h>

.section K_TEXT_START

.global kernel_image_start

.org 0x0
/* 256 bytes of some data */
/* exception table - must use 'ba' instructions for branches,
 * because it is elsewhere than the linker thinks
 */
.space 4096

kernel_image_start:
    /* Initialize OFW, might be needed before relocate_kernel? */
    lis r4, ofw@ha
    addi r4, r4, ofw@l
    stw r5, 0(r4)
    
    bl ofw_init
    bl preboot_read_config

    bl relocate_kernel
__after_reloc:
    /* Set stack to some more meaningful value */
    /* TODO: This is hardcoded for PearPC, must be changed later */
    lis r1, 0x70
    b main_bsp
    
relocate_kernel:
    /* TODO: We _know_ that pearpc loads it to 8MB, and
     * but it should be really generic
     */
    lis r4, 0x80 /* r4 is where data was loaded - 8MB */
    
    bl to_real_mode
    /* Now we are in real mode, copy first block and jump to it,
     * we are running in the loaded kernel now
     * We still have in r3 physical load kernel address
     */
    
    b __after_reloc /* We know in pearpc we are ok, so return,
                     * otherwise we should relocate kernel
                 * here
                     */

    

    
/* Turn off page translation
 * - assume that physical-loaded address is in r4
 */
to_real_mode:
    mflr r0
    
    lis   r5, ktext_start@ha // Expected start of kernel
    addi r5, r5, ktext_start@l
    
    add  r0, r4, r0     
    sub  r0, r0, r5         // r0 now contains physical return address
    
    mfmsr r3
    andis. r3, r3, (~MSR_DR | MSR_IR) >> 16
    mtspr SPRN_SRR0, r0
    mtspr SPRN_SRR1, r3
    sync            // Really needed? RFI should do it as well?
    RFI