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199 lines
7.2 KiB
199 lines
7.2 KiB
/* crypto/des/cfb_enc.c */ |
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/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) |
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* All rights reserved. |
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* |
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* This package is an SSL implementation written |
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* by Eric Young (eay@cryptsoft.com). |
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* The implementation was written so as to conform with Netscapes SSL. |
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* |
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* This library is free for commercial and non-commercial use as long as |
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* the following conditions are aheared to. The following conditions |
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* apply to all code found in this distribution, be it the RC4, RSA, |
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* lhash, DES, etc., code; not just the SSL code. The SSL documentation |
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* included with this distribution is covered by the same copyright terms |
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* except that the holder is Tim Hudson (tjh@cryptsoft.com). |
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* |
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* Copyright remains Eric Young's, and as such any Copyright notices in |
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* the code are not to be removed. |
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* If this package is used in a product, Eric Young should be given attribution |
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* as the author of the parts of the library used. |
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* This can be in the form of a textual message at program startup or |
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* in documentation (online or textual) provided with the package. |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* 1. Redistributions of source code must retain the copyright |
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* notice, this list of conditions and the following disclaimer. |
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* 2. Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in the |
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* documentation and/or other materials provided with the distribution. |
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* 3. All advertising materials mentioning features or use of this software |
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* must display the following acknowledgement: |
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* "This product includes cryptographic software written by |
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* Eric Young (eay@cryptsoft.com)" |
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* The word 'cryptographic' can be left out if the rouines from the library |
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* being used are not cryptographic related :-). |
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* 4. If you include any Windows specific code (or a derivative thereof) from |
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* the apps directory (application code) you must include an acknowledgement: |
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* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" |
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* |
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* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND |
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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* SUCH DAMAGE. |
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* |
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* The licence and distribution terms for any publically available version or |
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* derivative of this code cannot be changed. i.e. this code cannot simply be |
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* copied and put under another distribution licence |
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* [including the GNU Public Licence.] |
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*/ |
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#include "e_os.h" |
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#include "des_locl.h" |
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#include <assert.h> |
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/* |
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* The input and output are loaded in multiples of 8 bits. What this means is |
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* that if you hame numbits=12 and length=2 the first 12 bits will be |
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* retrieved from the first byte and half the second. The second 12 bits |
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* will come from the 3rd and half the 4th byte. |
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*/ |
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/* |
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* Until Aug 1 2003 this function did not correctly implement CFB-r, so it |
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* will not be compatible with any encryption prior to that date. Ben. |
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*/ |
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void DES_cfb_encrypt(const unsigned char *in, unsigned char *out, int numbits, |
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long length, DES_key_schedule *schedule, |
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DES_cblock *ivec, int enc) |
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{ |
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register DES_LONG d0, d1, v0, v1; |
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register unsigned long l = length; |
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register int num = numbits / 8, n = (numbits + 7) / 8, i, rem = |
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numbits % 8; |
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DES_LONG ti[2]; |
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unsigned char *iv; |
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#ifndef L_ENDIAN |
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unsigned char ovec[16]; |
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#else |
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unsigned int sh[4]; |
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unsigned char *ovec = (unsigned char *)sh; |
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/* I kind of count that compiler optimizes away this assertioni, */ |
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assert(sizeof(sh[0]) == 4); /* as this holds true for all, */ |
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/* but 16-bit platforms... */ |
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#endif |
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if (numbits <= 0 || numbits > 64) |
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return; |
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iv = &(*ivec)[0]; |
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c2l(iv, v0); |
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c2l(iv, v1); |
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if (enc) { |
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while (l >= (unsigned long)n) { |
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l -= n; |
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ti[0] = v0; |
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ti[1] = v1; |
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DES_encrypt1((DES_LONG *)ti, schedule, DES_ENCRYPT); |
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c2ln(in, d0, d1, n); |
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in += n; |
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d0 ^= ti[0]; |
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d1 ^= ti[1]; |
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l2cn(d0, d1, out, n); |
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out += n; |
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/* |
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* 30-08-94 - eay - changed because l>>32 and l<<32 are bad under |
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* gcc :-( |
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*/ |
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if (numbits == 32) { |
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v0 = v1; |
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v1 = d0; |
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} else if (numbits == 64) { |
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v0 = d0; |
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v1 = d1; |
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} else { |
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#ifndef L_ENDIAN |
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iv = &ovec[0]; |
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l2c(v0, iv); |
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l2c(v1, iv); |
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l2c(d0, iv); |
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l2c(d1, iv); |
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#else |
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sh[0] = v0, sh[1] = v1, sh[2] = d0, sh[3] = d1; |
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#endif |
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if (rem == 0) |
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memmove(ovec, ovec + num, 8); |
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else |
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for (i = 0; i < 8; ++i) |
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ovec[i] = ovec[i + num] << rem | |
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ovec[i + num + 1] >> (8 - rem); |
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#ifdef L_ENDIAN |
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v0 = sh[0], v1 = sh[1]; |
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#else |
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iv = &ovec[0]; |
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c2l(iv, v0); |
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c2l(iv, v1); |
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#endif |
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} |
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} |
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} else { |
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while (l >= (unsigned long)n) { |
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l -= n; |
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ti[0] = v0; |
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ti[1] = v1; |
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DES_encrypt1((DES_LONG *)ti, schedule, DES_ENCRYPT); |
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c2ln(in, d0, d1, n); |
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in += n; |
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/* |
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* 30-08-94 - eay - changed because l>>32 and l<<32 are bad under |
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* gcc :-( |
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*/ |
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if (numbits == 32) { |
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v0 = v1; |
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v1 = d0; |
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} else if (numbits == 64) { |
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v0 = d0; |
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v1 = d1; |
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} else { |
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#ifndef L_ENDIAN |
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iv = &ovec[0]; |
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l2c(v0, iv); |
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l2c(v1, iv); |
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l2c(d0, iv); |
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l2c(d1, iv); |
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#else |
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sh[0] = v0, sh[1] = v1, sh[2] = d0, sh[3] = d1; |
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#endif |
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if (rem == 0) |
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memmove(ovec, ovec + num, 8); |
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else |
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for (i = 0; i < 8; ++i) |
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ovec[i] = ovec[i + num] << rem | |
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ovec[i + num + 1] >> (8 - rem); |
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#ifdef L_ENDIAN |
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v0 = sh[0], v1 = sh[1]; |
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#else |
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iv = &ovec[0]; |
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c2l(iv, v0); |
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c2l(iv, v1); |
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#endif |
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} |
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d0 ^= ti[0]; |
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d1 ^= ti[1]; |
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l2cn(d0, d1, out, n); |
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out += n; |
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} |
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} |
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iv = &(*ivec)[0]; |
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l2c(v0, iv); |
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l2c(v1, iv); |
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v0 = v1 = d0 = d1 = ti[0] = ti[1] = 0; |
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}
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