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96 lines
1.9 KiB
96 lines
1.9 KiB
/*
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* Copyright (C) Paul Mackerras 1997.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* NOTE: this code runs in 32 bit mode and is packaged as ELF32.
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*/
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#include "ppc_asm.h"
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.text
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/* a procedure descriptor used when booting this as a COFF file */
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.globl _zimage_start_opd
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_zimage_start_opd:
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.long _zimage_start, 0, 0, 0
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.weak _zimage_start
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.globl _zimage_start
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_zimage_start:
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.globl _zimage_start_lib
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_zimage_start_lib:
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/* Work out the offset between the address we were linked at
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and the address where we're running. */
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bl 1f
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1: mflr r0
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lis r9,1b@ha
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addi r9,r9,1b@l
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subf. r0,r9,r0
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beq 3f /* if running at same address as linked */
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/* The .got2 section contains a list of addresses, so add
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the address offset onto each entry. */
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lis r9,__got2_start@ha
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addi r9,r9,__got2_start@l
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lis r8,__got2_end@ha
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addi r8,r8,__got2_end@l
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subf. r8,r9,r8
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beq 3f
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srwi. r8,r8,2
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mtctr r8
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add r9,r0,r9
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2: lwz r8,0(r9)
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add r8,r8,r0
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stw r8,0(r9)
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addi r9,r9,4
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bdnz 2b
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/* Do a cache flush for our text, in case the loader didn't */
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3: lis r9,_start@ha
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addi r9,r9,_start@l
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add r9,r0,r9
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lis r8,_etext@ha
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addi r8,r8,_etext@l
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add r8,r0,r8
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4: dcbf r0,r9
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icbi r0,r9
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addi r9,r9,0x20
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cmplw cr0,r9,r8
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blt 4b
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sync
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isync
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/* Clear the BSS */
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lis r9,__bss_start@ha
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addi r9,r9,__bss_start@l
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add r9,r0,r9
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lis r8,_end@ha
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addi r8,r8,_end@l
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add r8,r0,r8
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li r10,0
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5: stw r10,0(r9)
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addi r9,r9,4
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cmplw cr0,r9,r8
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blt 5b
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/* Possibly set up a custom stack */
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.weak _platform_stack_top
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lis r8,_platform_stack_top@ha
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addi r8,r8,_platform_stack_top@l
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cmpwi r8,0
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beq 6f
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add r8,r0,r8
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lwz r1,0(r8)
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add r1,r0,r1
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li r0,0
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stwu r0,-16(r1) /* establish a stack frame */
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6:
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/* Call platform_init() */
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bl platform_init
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/* Call start */
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b start
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