49 lines
1.1 KiB
ArmAsm
49 lines
1.1 KiB
ArmAsm
/*
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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 <asm/ppc_asm.h>
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.text
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.globl _start
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_start:
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lis r9,_start@h
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lis r8,_etext@ha
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addi r8,r8,_etext@l
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1: dcbf r0,r9
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icbi r0,r9
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addi r9,r9,0x20
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cmplwi 0,r9,8
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blt 1b
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sync
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isync
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## Clear out the BSS as per ANSI C requirements
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lis r7,_end@ha
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addi r7,r7,_end@l # r7 = &_end
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lis r8,__bss_start@ha #
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addi r8,r8,__bss_start@l # r8 = &_bss_start
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## Determine how large an area, in number of words, to clear
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subf r7,r8,r7 # r7 = &_end - &_bss_start + 1
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addi r7,r7,3 # r7 += 3
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srwi. r7,r7,2 # r7 = size in words.
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beq 3f # If the size is zero, don't bother
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addi r8,r8,-4 # r8 -= 4
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mtctr r7 # SPRN_CTR = number of words to clear
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li r0,0 # r0 = 0
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2: stwu r0,4(r8) # Clear out a word
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bdnz 2b # Keep clearing until done
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3:
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b start
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