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root/arch/x86/crypto/twofish-i586-asm_32.S

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/***************************************************************************
*   Copyright (C) 2006 by Joachim Fritschi, <jfritschi@freenet.de>        *
*                                                                         *
*   This program 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.                                   *
*                                                                         *
*   This program 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 this program; if not, write to the                         *
*   Free Software Foundation, Inc.,                                       *
*   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
***************************************************************************/

.file "twofish-i586-asm.S"
.text

#include <asm/asm-offsets.h>

/* return adress at 0 */

#define in_blk    12  /* input byte array address parameter*/
#define out_blk   8  /* output byte array address parameter*/
#define tfm       4  /* Twofish context structure */

#define a_offset        0
#define b_offset        4
#define c_offset        8
#define d_offset        12

/* Structure of the crypto context struct*/

#define s0      0       /* S0 Array 256 Words each */
#define s1      1024    /* S1 Array */
#define s2      2048    /* S2 Array */
#define s3      3072    /* S3 Array */
#define w       4096    /* 8 whitening keys (word) */
#define k       4128    /* key 1-32 ( word ) */

/* define a few register aliases to allow macro substitution */

#define R0D    %eax
#define R0B    %al
#define R0H    %ah

#define R1D    %ebx
#define R1B    %bl
#define R1H    %bh

#define R2D    %ecx
#define R2B    %cl
#define R2H    %ch

#define R3D    %edx
#define R3B    %dl
#define R3H    %dh


/* performs input whitening */
#define input_whitening(src,context,offset)\
        xor     w+offset(context),      src;

/* performs input whitening */
#define output_whitening(src,context,offset)\
        xor     w+16+offset(context),   src;

/*
 * a input register containing a (rotated 16)
 * b input register containing b
 * c input register containing c
 * d input register containing d (already rol $1)
 * operations on a and b are interleaved to increase performance
 */
#define encrypt_round(a,b,c,d,round)\
        push    d ## D;\
        movzx   b ## B,         %edi;\
        mov     s1(%ebp,%edi,4),d ## D;\
        movzx   a ## B,         %edi;\
        mov     s2(%ebp,%edi,4),%esi;\
        movzx   b ## H,         %edi;\
        ror     $16,            b ## D;\
        xor     s2(%ebp,%edi,4),d ## D;\
        movzx   a ## H,         %edi;\
        ror     $16,            a ## D;\
        xor     s3(%ebp,%edi,4),%esi;\
        movzx   b ## B,         %edi;\
        xor     s3(%ebp,%edi,4),d ## D;\
        movzx   a ## B,         %edi;\
        xor     (%ebp,%edi,4),  %esi;\
        movzx   b ## H,         %edi;\
        ror     $15,            b ## D;\
        xor     (%ebp,%edi,4),  d ## D;\
        movzx   a ## H,         %edi;\
        xor     s1(%ebp,%edi,4),%esi;\
        pop     %edi;\
        add     d ## D,         %esi;\
        add     %esi,           d ## D;\
        add     k+round(%ebp),  %esi;\
        xor     %esi,           c ## D;\
        rol     $15,            c ## D;\
        add     k+4+round(%ebp),d ## D;\
        xor     %edi,           d ## D;

/*
 * a input register containing a (rotated 16)
 * b input register containing b
 * c input register containing c
 * d input register containing d (already rol $1)
 * operations on a and b are interleaved to increase performance
 * last round has different rotations for the output preparation
 */
#define encrypt_last_round(a,b,c,d,round)\
        push    d ## D;\
        movzx   b ## B,         %edi;\
        mov     s1(%ebp,%edi,4),d ## D;\
        movzx   a ## B,         %edi;\
        mov     s2(%ebp,%edi,4),%esi;\
        movzx   b ## H,         %edi;\
        ror     $16,            b ## D;\
        xor     s2(%ebp,%edi,4),d ## D;\
        movzx   a ## H,         %edi;\
        ror     $16,            a ## D;\
        xor     s3(%ebp,%edi,4),%esi;\
        movzx   b ## B,         %edi;\
        xor     s3(%ebp,%edi,4),d ## D;\
        movzx   a ## B,         %edi;\
        xor     (%ebp,%edi,4),  %esi;\
        movzx   b ## H,         %edi;\
        ror     $16,            b ## D;\
        xor     (%ebp,%edi,4),  d ## D;\
        movzx   a ## H,         %edi;\
        xor     s1(%ebp,%edi,4),%esi;\
        pop     %edi;\
        add     d ## D,         %esi;\
        add     %esi,           d ## D;\
        add     k+round(%ebp),  %esi;\
        xor     %esi,           c ## D;\
        ror     $1,             c ## D;\
        add     k+4+round(%ebp),d ## D;\
        xor     %edi,           d ## D;

/*
 * a input register containing a
 * b input register containing b (rotated 16)
 * c input register containing c
 * d input register containing d (already rol $1)
 * operations on a and b are interleaved to increase performance
 */
#define decrypt_round(a,b,c,d,round)\
        push    c ## D;\
        movzx   a ## B,         %edi;\
        mov     (%ebp,%edi,4),  c ## D;\
        movzx   b ## B,         %edi;\
        mov     s3(%ebp,%edi,4),%esi;\
        movzx   a ## H,         %edi;\
        ror     $16,            a ## D;\
        xor     s1(%ebp,%edi,4),c ## D;\
        movzx   b ## H,         %edi;\
        ror     $16,            b ## D;\
        xor     (%ebp,%edi,4),  %esi;\
        movzx   a ## B,         %edi;\
        xor     s2(%ebp,%edi,4),c ## D;\
        movzx   b ## B,         %edi;\
        xor     s1(%ebp,%edi,4),%esi;\
        movzx   a ## H,         %edi;\
        ror     $15,            a ## D;\
        xor     s3(%ebp,%edi,4),c ## D;\
        movzx   b ## H,         %edi;\
        xor     s2(%ebp,%edi,4),%esi;\
        pop     %edi;\
        add     %esi,           c ## D;\
        add     c ## D,         %esi;\
        add     k+round(%ebp),  c ## D;\
        xor     %edi,           c ## D;\
        add     k+4+round(%ebp),%esi;\
        xor     %esi,           d ## D;\
        rol     $15,            d ## D;

/*
 * a input register containing a
 * b input register containing b (rotated 16)
 * c input register containing c
 * d input register containing d (already rol $1)
 * operations on a and b are interleaved to increase performance
 * last round has different rotations for the output preparation
 */
#define decrypt_last_round(a,b,c,d,round)\
        push    c ## D;\
        movzx   a ## B,         %edi;\
        mov     (%ebp,%edi,4),  c ## D;\
        movzx   b ## B,         %edi;\
        mov     s3(%ebp,%edi,4),%esi;\
        movzx   a ## H,         %edi;\
        ror     $16,            a ## D;\
        xor     s1(%ebp,%edi,4),c ## D;\
        movzx   b ## H,         %edi;\
        ror     $16,            b ## D;\
        xor     (%ebp,%edi,4),  %esi;\
        movzx   a ## B,         %edi;\
        xor     s2(%ebp,%edi,4),c ## D;\
        movzx   b ## B,         %edi;\
        xor     s1(%ebp,%edi,4),%esi;\
        movzx   a ## H,         %edi;\
        ror     $16,            a ## D;\
        xor     s3(%ebp,%edi,4),c ## D;\
        movzx   b ## H,         %edi;\
        xor     s2(%ebp,%edi,4),%esi;\
        pop     %edi;\
        add     %esi,           c ## D;\
        add     c ## D,         %esi;\
        add     k+round(%ebp),  c ## D;\
        xor     %edi,           c ## D;\
        add     k+4+round(%ebp),%esi;\
        xor     %esi,           d ## D;\
        ror     $1,             d ## D;

.align 4
.global twofish_enc_blk
.global twofish_dec_blk

twofish_enc_blk:
        push    %ebp                    /* save registers according to calling convention*/
        push    %ebx
        push    %esi
        push    %edi

        mov     tfm + 16(%esp), %ebp    /* abuse the base pointer: set new base bointer to the crypto tfm */
        add     $crypto_tfm_ctx_offset, %ebp    /* ctx adress */
        mov     in_blk+16(%esp),%edi    /* input adress in edi */

        mov     (%edi),         %eax
        mov     b_offset(%edi), %ebx
        mov     c_offset(%edi), %ecx
        mov     d_offset(%edi), %edx
        input_whitening(%eax,%ebp,a_offset)
        ror     $16,    %eax
        input_whitening(%ebx,%ebp,b_offset)
        input_whitening(%ecx,%ebp,c_offset)
        input_whitening(%edx,%ebp,d_offset)
        rol     $1,     %edx

        encrypt_round(R0,R1,R2,R3,0);
        encrypt_round(R2,R3,R0,R1,8);
        encrypt_round(R0,R1,R2,R3,2*8);
        encrypt_round(R2,R3,R0,R1,3*8);
        encrypt_round(R0,R1,R2,R3,4*8);
        encrypt_round(R2,R3,R0,R1,5*8);
        encrypt_round(R0,R1,R2,R3,6*8);
        encrypt_round(R2,R3,R0,R1,7*8);
        encrypt_round(R0,R1,R2,R3,8*8);
        encrypt_round(R2,R3,R0,R1,9*8);
        encrypt_round(R0,R1,R2,R3,10*8);
        encrypt_round(R2,R3,R0,R1,11*8);
        encrypt_round(R0,R1,R2,R3,12*8);
        encrypt_round(R2,R3,R0,R1,13*8);
        encrypt_round(R0,R1,R2,R3,14*8);
        encrypt_last_round(R2,R3,R0,R1,15*8);

        output_whitening(%eax,%ebp,c_offset)
        output_whitening(%ebx,%ebp,d_offset)
        output_whitening(%ecx,%ebp,a_offset)
        output_whitening(%edx,%ebp,b_offset)
        mov     out_blk+16(%esp),%edi;
        mov     %eax,           c_offset(%edi)
        mov     %ebx,           d_offset(%edi)
        mov     %ecx,           (%edi)
        mov     %edx,           b_offset(%edi)

        pop     %edi
        pop     %esi
        pop     %ebx
        pop     %ebp
        mov     $1,     %eax
        ret

twofish_dec_blk:
        push    %ebp                    /* save registers according to calling convention*/
        push    %ebx
        push    %esi
        push    %edi


        mov     tfm + 16(%esp), %ebp    /* abuse the base pointer: set new base bointer to the crypto tfm */
        add     $crypto_tfm_ctx_offset, %ebp    /* ctx adress */
        mov     in_blk+16(%esp),%edi    /* input adress in edi */

        mov     (%edi),         %eax
        mov     b_offset(%edi), %ebx
        mov     c_offset(%edi), %ecx
        mov     d_offset(%edi), %edx
        output_whitening(%eax,%ebp,a_offset)
        output_whitening(%ebx,%ebp,b_offset)
        ror     $16,    %ebx
        output_whitening(%ecx,%ebp,c_offset)
        output_whitening(%edx,%ebp,d_offset)
        rol     $1,     %ecx

        decrypt_round(R0,R1,R2,R3,15*8);
        decrypt_round(R2,R3,R0,R1,14*8);
        decrypt_round(R0,R1,R2,R3,13*8);
        decrypt_round(R2,R3,R0,R1,12*8);
        decrypt_round(R0,R1,R2,R3,11*8);
        decrypt_round(R2,R3,R0,R1,10*8);
        decrypt_round(R0,R1,R2,R3,9*8);
        decrypt_round(R2,R3,R0,R1,8*8);
        decrypt_round(R0,R1,R2,R3,7*8);
        decrypt_round(R2,R3,R0,R1,6*8);
        decrypt_round(R0,R1,R2,R3,5*8);
        decrypt_round(R2,R3,R0,R1,4*8);
        decrypt_round(R0,R1,R2,R3,3*8);
        decrypt_round(R2,R3,R0,R1,2*8);
        decrypt_round(R0,R1,R2,R3,1*8);
        decrypt_last_round(R2,R3,R0,R1,0);

        input_whitening(%eax,%ebp,c_offset)
        input_whitening(%ebx,%ebp,d_offset)
        input_whitening(%ecx,%ebp,a_offset)
        input_whitening(%edx,%ebp,b_offset)
        mov     out_blk+16(%esp),%edi;
        mov     %eax,           c_offset(%edi)
        mov     %ebx,           d_offset(%edi)
        mov     %ecx,           (%edi)
        mov     %edx,           b_offset(%edi)

        pop     %edi
        pop     %esi
        pop     %ebx
        pop     %ebp
        mov     $1,     %eax
        ret

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