lzo1x_d.ash

开源的压缩算法 lzo 源码 ,open VPN 就是用这个算法

/* lzo1x_d.ash -- assembler implementation of the LZO1X decompression algorithm

   This file is part of the LZO real-time data compression library.

   Copyright (C) 2005 Markus Franz Xaver Johannes Oberhumer
   Copyright (C) 2004 Markus Franz Xaver Johannes Oberhumer
   Copyright (C) 2003 Markus Franz Xaver Johannes Oberhumer
   Copyright (C) 2002 Markus Franz Xaver Johannes Oberhumer
   Copyright (C) 2001 Markus Franz Xaver Johannes Oberhumer
   Copyright (C) 2000 Markus Franz Xaver Johannes Oberhumer
   Copyright (C) 1999 Markus Franz Xaver Johannes Oberhumer
   Copyright (C) 1998 Markus Franz Xaver Johannes Oberhumer
   Copyright (C) 1997 Markus Franz Xaver Johannes Oberhumer
   Copyright (C) 1996 Markus Franz Xaver Johannes Oberhumer
   All Rights Reserved.

   The LZO library is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License,
   version 2, as published by the Free Software Foundation.

   The LZO library 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 the LZO library; see the file COPYING.
   If not, write to the Free Software Foundation, Inc.,
   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.

   Markus F.X.J. Oberhumer
   <[e-mail]>
   http://www.oberhumer.com/opensource/lzo/
 */


/*
 * This file has been adapted from code generously contributed by
 * Laszlo Molnar aka ML1050 <[e-mail]>
 *
 * Many thanks, Laszlo !
 *
 * I (Markus) have optimized the fast version a lot, so enjoy...
 */


#if !defined(LZO1X) && !defined(LZO1Y)
#  define LZO1X
#endif

#if defined(LZO_FAST)
#  define NN    3
#else
#  define NN    0
#endif


/***********************************************************************
// init
************************************************************************/

        xorl    %eax,%eax
        xorl    %ebx,%ebx       /* high bits 9-32 stay 0 */
        lodsb
        cmpb    $17,%al
        jbe     .L01
        subb    $17-NN,%al
#if defined(LZO_FAST)
        jmp     .LFLR
#else
        cmpb    $4,%al
        jae     .LFLR
#if 1
        TEST_OP((%edi,%eax),%edx)
        TEST_IP((%esi,%eax),%edx)
        movl    %eax,%ecx
        jmp     .LFLR2
#else
        jmp     .LFLR3
#endif
#endif


/***********************************************************************
// literal run
************************************************************************/

0:      addl    N_255,%eax
        TEST_IP(18(%esi,%eax),%edx)     /* minimum */
1:      movb    (%esi),%bl
        incl    %esi
        orb     %bl,%bl
        jz      0b
        leal    18+NN(%eax,%ebx),%eax
        jmp     3f


        ALIGN3
.L00:
#ifdef LZO_DEBUG
    andl $0xffffff00,%eax ; jnz .L_assert_fail
    andl $0xffffff00,%ebx ; jnz .L_assert_fail
    xorl %eax,%eax ; xorl %ebx,%ebx
    xorl %ecx,%ecx ; xorl %edx,%edx
#endif
        TEST_IP_R(%esi)
        LODSB
.L01:
        cmpb    $16,%al
        jae     .LMATCH

/* a literal run */
        orb     %al,%al
        jz      1b
        addl    $3+NN,%eax
3:
.LFLR:
        TEST_OP(-NN(%edi,%eax),%edx)
        TEST_IP(-NN(%esi,%eax),%edx)
#if defined(LZO_FAST)
        movl    %eax,%ecx
        NOTL_3(%eax)
        shrl    $2,%ecx
        andl    N_3,%eax
        COPYL(%esi,%edi,%edx)
        subl    %eax,%esi
        subl    %eax,%edi
#else
        movl    %eax,%ecx
        shrl    $2,%eax
        andl    N_3,%ecx
        COPYL_C(%esi,%edi,%edx,%eax)
.LFLR2:
        rep
        movsb
#endif

#ifdef LZO_DEBUG
    andl $0xffffff00,%eax ; jnz .L_assert_fail
    andl $0xffffff00,%ebx ; jnz .L_assert_fail
    xorl %eax,%eax ; xorl %ebx,%ebx
    xorl %ecx,%ecx ; xorl %edx,%edx
#endif
        LODSB
        cmpb    $16,%al
        jae     .LMATCH


/***********************************************************************
// R1
************************************************************************/

        TEST_OP(3(%edi),%edx)
        shrl    $2,%eax
        movb    (%esi),%bl
#if defined(LZO1X)
        leal    -0x801(%edi),%edx
#elif defined(LZO1Y)
        leal    -0x401(%edi),%edx
#endif
        leal    (%eax,%ebx,4),%eax
        incl    %esi
        subl    %eax,%edx
        TEST_LOOKBEHIND(%edx)
#if defined(LZO_FAST)
        movl    (%edx),%ecx
        movl    %ecx,(%edi)
#else
        movb    (%edx),%al
        movb    %al,(%edi)
        movb    1(%edx),%al
        movb    %al,1(%edi)
        movb    2(%edx),%al
        movb    %al,2(%edi)
#endif
        addl    N_3,%edi
        jmp     .LMDONE


/***********************************************************************
// M2
************************************************************************/

        ALIGN3
.LMATCH:
        cmpb    $64,%al
        jb      .LM3MATCH

/* a M2 match */
        movl    %eax,%ecx
        shrl    $2,%eax
        leal    -1(%edi),%edx
#if defined(LZO1X)
        andl    $7,%eax
        movb    (%esi),%bl
        shrl    $5,%ecx
        leal    (%eax,%ebx,8),%eax
#elif defined(LZO1Y)
        andl    N_3,%eax
        movb    (%esi),%bl
        shrl    $4,%ecx
        leal    (%eax,%ebx,4),%eax
#endif
        incl    %esi
        subl    %eax,%edx

#if defined(LZO_FAST)
#if defined(LZO1X)
        addl    $1+3,%ecx
#elif defined(LZO1Y)
        addl    $2,%ecx
#endif
#else
#if defined(LZO1X)
        incl    %ecx
#elif defined(LZO1Y)
        decl    %ecx
#endif
#endif

        cmpl    N_3,%eax
        jae     .LCOPYLONG
        jmp     .LCOPYBYTE


/***********************************************************************
// M3
************************************************************************/

0:      addl    N_255,%eax
        TEST_IP(3(%esi),%edx)       /* minimum */
1:      movb    (%esi),%bl
        incl    %esi
        orb     %bl,%bl
        jz      0b
        leal    33+NN(%eax,%ebx),%ecx
        xorl    %eax,%eax
        jmp     3f


        ALIGN3
.LM3MATCH:
        cmpb    $32,%al
        jb      .LM4MATCH

/* a M3 match */
        andl    $31,%eax
        jz      1b
        lea     2+NN(%eax),%ecx
3:
#ifdef LZO_DEBUG
    andl $0xffff0000,%eax ; jnz .L_assert_fail
#endif
        movw    (%esi),%ax
        leal    -1(%edi),%edx
        shrl    $2,%eax
        addl    $2,%esi
        subl    %eax,%edx

        cmpl    N_3,%eax
        jb      .LCOPYBYTE


/***********************************************************************
// copy match
************************************************************************/

        ALIGN1
.LCOPYLONG:                      /* copy match using longwords */
        TEST_LOOKBEHIND(%edx)
#if defined(LZO_FAST)
        leal    -3(%edi,%ecx),%eax
        shrl    $2,%ecx
        TEST_OP_R(%eax)
        COPYL(%edx,%edi,%ebx)
        movl    %eax,%edi
        xorl    %ebx,%ebx
#else
        TEST_OP((%edi,%ecx),%eax)
        movl    %ecx,%ebx
        shrl    $2,%ebx
        jz      2f
        COPYL_C(%edx,%edi,%eax,%ebx)
        andl    N_3,%ecx
        jz      1f
2:      COPYB_C(%edx,%edi,%al,%ecx)
1:
#endif

.LMDONE:
        movb    -2(%esi),%al
        andl    N_3,%eax
        jz      .L00
.LFLR3:
        TEST_OP((%edi,%eax),%edx)
        TEST_IP((%esi,%eax),%edx)
#if defined(LZO_FAST)
        movl    (%esi),%edx
        addl    %eax,%esi
        movl    %edx,(%edi)
        addl    %eax,%edi
#else
        COPYB_C(%esi,%edi,%cl,%eax)
#endif

#ifdef LZO_DEBUG
    andl $0xffffff00,%eax ; jnz .L_assert_fail
    andl $0xffffff00,%ebx ; jnz .L_assert_fail
    xorl %eax,%eax ; xorl %ebx,%ebx
    xorl %ecx,%ecx ; xorl %edx,%edx
#endif
        LODSB
        jmp     .LMATCH


        ALIGN3
.LCOPYBYTE:                      /* copy match using bytes */
        TEST_LOOKBEHIND(%edx)
        TEST_OP(-NN(%edi,%ecx),%eax)
        xchgl   %edx,%esi
#if defined(LZO_FAST)
        subl    N_3,%ecx
#endif
        rep
        movsb
        movl    %edx,%esi
        jmp     .LMDONE


/***********************************************************************
// M4
************************************************************************/

0:      addl    N_255,%ecx
        TEST_IP(3(%esi),%edx)       /* minimum */
1:      movb    (%esi),%bl
        incl    %esi
        orb     %bl,%bl
        jz      0b
        leal    9+NN(%ebx,%ecx),%ecx
        jmp     3f


        ALIGN3
.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:
#ifdef LZO_DEBUG
    movl %eax,%edx ; andl $0xfffe0000,%edx ; jnz .L_assert_fail
#endif
        movw    (%esi),%ax
        addl    $2,%esi
        leal    -0x4000(%edi),%edx
        shrl    $2,%eax
        jz      .LEOF
        subl    %eax,%edx
        jmp     .LCOPYLONG


/***********************************************************************
// M1
************************************************************************/

        ALIGN3
.LM1MATCH:
/* a M1 match */
        TEST_OP(2(%edi),%edx)
        shrl    $2,%eax
        movb    (%esi),%bl
        leal    -1(%edi),%edx
        leal    (%eax,%ebx,4),%eax
        incl    %esi
        subl    %eax,%edx
        TEST_LOOKBEHIND(%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


/*
vi:ts=4
*/