/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 1996-2002 Markus Franz Xaver Johannes Oberhumer
* Copyright (C) 2003,2007 Free Software Foundation, Inc.
*
* GRUB 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 3 of the License, or
* (at your option) any later version.
*
* GRUB is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GRUB. If not, see .
*/
/*
* This code was stolen from the files enter.sh, leave.sh, lzo1x_d.sh,
* lzo1x_f.s and lzo_asm.h in LZO version 1.08, and was heavily modified
* to adapt it to GRUB's requirement.
*
* See , for more information
* about LZO.
*/
#define INP 4+16(%esp)
#define INS 8+16(%esp)
#define OUTP 12+16(%esp)
#define NN 3
#define N_3 %ebp
#define N_255 $255
#define LODSB movb (%esi), %al ; incl %esi
#define NOTL_3(r) xorl N_3, r
#define MOVSL(r1,r2,x) movl (r1), x ; addl $4, r1 ; movl x, (r2) ; addl $4, r2
#define COPYL_C(r1,r2,x,rc) 9: MOVSL(r1,r2,x) ; decl rc ; jnz 9b
#define COPYL(r1,r2,x) COPYL_C(r1,r2,x,%ecx)
lzo1x_decompress:
pushl %ebp
pushl %edi
pushl %esi
pushl %ebx
cld
movl INP, %esi
movl OUTP, %edi
movl $3, %ebp
xorl %eax, %eax
xorl %ebx, %ebx /* high bits 9-32 stay 0 */
lodsb
cmpb $17, %al
jbe .L01
subb $17-NN, %al
jmp .LFLR
/***********************************************************************
// literal run
************************************************************************/
0: addl N_255, %eax
1: movb (%esi), %bl
incl %esi
orb %bl, %bl
jz 0b
leal 18+NN(%eax,%ebx), %eax
jmp 3f
.align 8
.L00:
LODSB
.L01:
cmpb $16, %al
jae .LMATCH
/* a literal run */
orb %al, %al
jz 1b
addl $3+NN, %eax
3:
.LFLR:
movl %eax, %ecx
NOTL_3(%eax)
shrl $2, %ecx
andl N_3, %eax
COPYL(%esi,%edi,%edx)
subl %eax, %esi
subl %eax, %edi
LODSB
cmpb $16, %al
jae .LMATCH
/***********************************************************************
// R1
************************************************************************/
shrl $2, %eax
movb (%esi), %bl
leal -0x801(%edi), %edx
leal (%eax,%ebx,4), %eax
incl %esi
subl %eax, %edx
movl (%edx), %ecx
movl %ecx, (%edi)
addl N_3, %edi
jmp .LMDONE
/***********************************************************************
// M2
************************************************************************/
.align 8
.LMATCH:
cmpb $64, %al
jb .LM3MATCH
/* a M2 match */
movl %eax, %ecx
shrl $2, %eax
leal -1(%edi), %edx
andl $7, %eax
movb (%esi), %bl
shrl $5, %ecx
leal (%eax,%ebx,8), %eax
incl %esi
subl %eax, %edx
addl $1+3, %ecx
cmpl N_3, %eax
jae .LCOPYLONG
jmp .LCOPYBYTE
/***********************************************************************
// M3
************************************************************************/
0: addl N_255, %eax
1: movb (%esi), %bl
incl %esi
orb %bl, %bl
jz 0b
leal 33+NN(%eax,%ebx), %ecx
xorl %eax, %eax
jmp 3f
.align 8
.LM3MATCH:
cmpb $32, %al
jb .LM4MATCH
/* a M3 match */
andl $31, %eax
jz 1b
lea 2+NN(%eax), %ecx
3:
movw (%esi), %ax
leal -1(%edi), %edx
shrl $2, %eax
addl $2, %esi
subl %eax, %edx
cmpl N_3, %eax
jb .LCOPYBYTE
/***********************************************************************
// copy match
************************************************************************/
.align 2
.LCOPYLONG: /* copy match using longwords */
leal -3(%edi,%ecx), %eax
shrl $2, %ecx
COPYL(%edx,%edi,%ebx)
movl %eax, %edi
xorl %ebx, %ebx
.LMDONE:
movb -2(%esi), %al
andl N_3, %eax
jz .L00
.LFLR3:
movl (%esi), %edx
addl %eax, %esi
movl %edx, (%edi)
addl %eax, %edi
LODSB
jmp .LMATCH
.align 8
.LCOPYBYTE: /* copy match using bytes */
xchgl %edx,%esi
subl N_3,%ecx
rep
movsb
movl %edx, %esi
jmp .LMDONE
/***********************************************************************
// M4
************************************************************************/
0: addl N_255, %ecx
1: movb (%esi), %bl
incl %esi
orb %bl, %bl
jz 0b
leal 9+NN(%ebx,%ecx), %ecx
jmp 3f
.align 8
.LM4MATCH:
cmpb $16, %al
jb .LM1MATCH
/* a M4 match */
movl %eax, %ecx
andl $8, %eax
shll $13, %eax /* save in bit 16 */
andl $7, %ecx
jz 1b
addl $2+NN, %ecx
3:
movw (%esi), %ax
addl $2, %esi
leal -0x4000(%edi), %edx
shrl $2, %eax
jz .LEOF
subl %eax, %edx
jmp .LCOPYLONG
/***********************************************************************
// M1
************************************************************************/
.align 8
.LM1MATCH:
/* a M1 match */
shrl $2, %eax
movb (%esi), %bl
leal -1(%edi), %edx
leal (%eax,%ebx,4), %eax
incl %esi
subl %eax, %edx
movb (%edx), %al /* we must use this because edx can be edi-1 */
movb %al, (%edi)
movb 1(%edx), %bl
movb %bl, 1(%edi)
addl $2, %edi
jmp .LMDONE
/***********************************************************************
//
************************************************************************/
.LEOF:
/**** xorl %eax,%eax eax=0 from above */
cmpl $3+NN, %ecx /* ecx must be 3/6 */
setnz %al
/* check compressed size */
movl INP, %edx
addl INS, %edx
cmpl %edx, %esi /* check compressed size */
ja .L_input_overrun
jb .L_input_not_consumed
.L_leave:
negl %eax
jnz 1f
subl OUTP, %edi /* write back the uncompressed size */
movl %edi, %eax
1: popl %ebx
popl %esi
popl %edi
popl %ebp
ret
.L_input_not_consumed:
movl $8, %eax /* LZO_E_INPUT_NOT_CONSUMED */
jmp .L_leave
.L_input_overrun:
movl $4, %eax /* LZO_E_INPUT_OVERRUN */
jmp .L_leave
#undef INP
#undef INS
#undef OUTP
#undef NN
#undef NN
#undef N_3
#undef N_255
#undef LODSB
#undef NOTL_3
#undef MOVSL
#undef COPYL_C
#undef COPYL