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/* utils.c - TinyCrypt platform-dependent run-time operations */
/*
* Copyright (C) 2015 by Intel Corporation, All Rights Reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* - Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* - Neither the name of Intel Corporation nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <utils.h>
#include <string.h>
#define MASK_MOST_SIG_BIT 0x80
#define MASK_TWENTY_SEVEN 0x1b
uint32_t _copy(uint8_t *to, uint32_t to_len, const uint8_t *from, uint32_t from_len)
{
if (from_len <= to_len) {
(void)memcpy(to, from, from_len);
return from_len;
} else {
return TC_FAIL;
}
}
void _set(uint8_t *to, uint8_t val, uint32_t len)
{
(void)memset(to, val, len);
}
/* Doubles the value of a byte for values up to 127. Original 'return
* ((a<<1) ^ ((a>>7) * 0x1b))' re-written to avoid extra multiplicaiton which
* the compiler won't be able to optimize */
uint8_t _double_byte(uint8_t a)
{
return (a & MASK_MOST_SIG_BIT) ? ((a << 1) ^ MASK_TWENTY_SEVEN) : (a << 1);
}
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