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/* -*- asm -*-
* $ $
*
*/
/*
* Copyright (C) 1996-2002 Markus Franz Xaver Johannes Oberhumer
*
* This file is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* Originally this code was part of ucl the data compression library
* for upx the ``Ultimate Packer of eXecutables''.
*
* - Converted to gas assembly, and refitted to work with etherboot.
* Eric Biederman 20 Aug 2002
* - Merged the nrv2b decompressor into crt0.base of LinuxBIOS
* Eric Biederman 26 Sept 2002
*/
#include <arch/asm.h>
#include <arch/intel.h>
#if CONFIG_SMP==1
#include <cpu/p6/apic.h>
#endif
/*
* This is the entry code the code in .reset section
* jumps to this address.
*
*/
.section ".rom.data", "a", @progbits
.section ".rom.text", "ax", @progbits
intel_chip_post_macro(0x01) /* delay for chipsets */
#include "crt0_includes.h"
/* clear boot_complete flag */
xorl %ebp, %ebp
__main:
CONSOLE_DEBUG_TX_STRING($str_copying_to_ram)
/*
* Copy data into RAM and clear the BSS. Since these segments
* isn\'t really that big we just copy/clear using bytes, not
* double words.
*/
intel_chip_post_macro(0x11) /* post 11 */
cld /* clear direction flag */
/* copy linuxBIOS from it's initial load location to
* the location it is compiled to run at.
* Normally this is copying from FLASH ROM to RAM.
*/
#if !CONFIG_COMPRESS
movl $_liseg, %esi
movl $_iseg, %edi
movl $_eiseg, %ecx
subl %edi, %ecx
rep movsb
#else
leal 4+_liseg, %esi
leal _iseg, %edi
movl %ebp, %esp /* preserve %ebp */
movl $-1, %ebp /* last_m_off = -1 */
jmp dcl1_n2b
/* ------------- DECOMPRESSION -------------
Input:
%esi - source
%edi - dest
%ebp - -1
cld
Output:
%eax - 0
%ecx - 0
*/
.macro getbit bits
.if \bits == 1
addl %ebx, %ebx
jnz 1f
.endif
movl (%esi), %ebx
subl $-4, %esi /* sets carry flag */
adcl %ebx, %ebx
1:
.endm
decompr_literals_n2b:
movsb
decompr_loop_n2b:
addl %ebx, %ebx
jnz dcl2_n2b
dcl1_n2b:
getbit 32
dcl2_n2b:
jc decompr_literals_n2b
xorl %eax, %eax
incl %eax /* m_off = 1 */
loop1_n2b:
getbit 1
adcl %eax, %eax /* m_off = m_off*2 + getbit() */
getbit 1
jnc loop1_n2b /* while(!getbit()) */
xorl %ecx, %ecx
subl $3, %eax
jb decompr_ebpeax_n2b /* if (m_off == 2) goto decompr_ebpeax_n2b ? */
shll $8, %eax
movb (%esi), %al /* m_off = (m_off - 3)*256 + src[ilen++] */
incl %esi
xorl $-1, %eax
jz decompr_end_n2b /* if (m_off == 0xffffffff) goto decomp_end_n2b */
movl %eax, %ebp /* last_m_off = m_off ?*/
decompr_ebpeax_n2b:
getbit 1
adcl %ecx, %ecx /* m_len = getbit() */
getbit 1
adcl %ecx, %ecx /* m_len = m_len*2 + getbit()) */
jnz decompr_got_mlen_n2b /* if (m_len == 0) goto decompr_got_mlen_n2b */
incl %ecx /* m_len++ */
loop2_n2b:
getbit 1
adcl %ecx, %ecx /* m_len = m_len*2 + getbit() */
getbit 1
jnc loop2_n2b /* while(!getbit()) */
incl %ecx
incl %ecx /* m_len += 2 */
decompr_got_mlen_n2b:
cmpl $-0xd00, %ebp
adcl $1, %ecx /* m_len = m_len + 1 + (last_m_off > 0xd00) */
movl %esi, %edx
leal (%edi,%ebp), %esi /* m_pos = dst + olen + -m_off */
rep
movsb /* dst[olen++] = *m_pos++ while(m_len > 0) */
movl %edx, %esi
jmp decompr_loop_n2b
decompr_end_n2b:
intel_chip_post_macro(0x12) /* post 12 */
movl %esp, %ebp
#endif
CONSOLE_DEBUG_TX_STRING($str_pre_main)
leal _iseg, %edi
jmp %edi
.Lhlt:
intel_chip_post_macro(0xee) /* post fe */
hlt
jmp .Lhlt
.section ".rom.data"
str_copying_to_ram: .string "Copying LinuxBIOS to ram.\r\n"
str_pre_main: .string "Jumping to LinuxBIOS.\r\n"
.previous
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