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bignum_core: Extracted mbedtls_mpi_shift_l from prototype

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Signed-off-by: Minos Galanakis <minos.galanakis@arm.com>
This commit is contained in:
Minos Galanakis 2023-04-20 12:18:41 +01:00
parent ad450d5a92
commit ad808dd5f1
2 changed files with 60 additions and 0 deletions
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48
library/bignum_core.c
View File

@ -353,6 +353,54 @@ void mbedtls_mpi_core_shift_r(mbedtls_mpi_uint *X, size_t limbs,
}
}
int mbedtls_mpi_shift_l( mbedtls_mpi *X, size_t count )
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
size_t i, v0, t1;
mbedtls_mpi_uint r0 = 0, r1;
MPI_VALIDATE_RET( X != NULL );
v0 = count / (biL );
t1 = count & (biL - 1);
i = mbedtls_mpi_bitlen( X ) + count;
if( X->n * biL < i )
MBEDTLS_MPI_CHK( mbedtls_mpi_grow( X, BITS_TO_LIMBS( i ) ) );
ret = 0;
/*
* shift by count / limb_size
*/
if( v0 > 0 )
{
for( i = X->n; i > v0; i-- )
X->p[i - 1] = X->p[i - v0 - 1];
for( ; i > 0; i-- )
X->p[i - 1] = 0;
}
/*
* shift by count % limb_size
*/
if( t1 > 0 )
{
for( i = v0; i < X->n; i++ )
{
r1 = X->p[i] >> (biL - t1);
X->p[i] <<= t1;
X->p[i] |= r0;
r0 = r1;
}
}
cleanup:
return( ret );
}
mbedtls_mpi_uint mbedtls_mpi_core_add(mbedtls_mpi_uint *X,
const mbedtls_mpi_uint *A,
const mbedtls_mpi_uint *B,

12
library/bignum_core.h
View File

@ -293,6 +293,18 @@ int mbedtls_mpi_core_write_be(const mbedtls_mpi_uint *A,
void mbedtls_mpi_core_shift_r(mbedtls_mpi_uint *X, size_t limbs,
size_t count);
/**
* \brief Perform a left-shift on an MPI: X <<= count
*
* \param X The MPI to shift. This must point to an initialized MPI.
* \param count The number of bits to shift by.
*
* \return \c 0 if successful.
* \return #MBEDTLS_ERR_MPI_ALLOC_FAILED if a memory allocation failed.
* \return Another negative error code on different kinds of failure.
*/
int mbedtls_mpi_shift_l( mbedtls_mpi *X, size_t count );
/**
* \brief Add two fixed-size large unsigned integers, returning the carry.
*