126 lines
3.3 KiB
C
126 lines
3.3 KiB
C
/*
|
|
* Multi-precision integer library
|
|
*
|
|
* Copyright The Mbed TLS Contributors
|
|
* SPDX-License-Identifier: Apache-2.0
|
|
*
|
|
* Licensed under the Apache License, Version 2.0 (the "License"); you may
|
|
* not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
|
|
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*/
|
|
|
|
#include "common.h"
|
|
|
|
#if defined(MBEDTLS_BIGNUM_C)
|
|
|
|
#include "mbedtls/bignum.h"
|
|
#include "bignum_core.h"
|
|
#include "bn_mul.h"
|
|
|
|
#include <string.h>
|
|
|
|
void MPI_CORE(montmul)( mbedtls_mpi_uint *X,
|
|
const mbedtls_mpi_uint *A,
|
|
const mbedtls_mpi_uint *B,
|
|
size_t B_len,
|
|
const mbedtls_mpi_uint *N,
|
|
size_t n,
|
|
mbedtls_mpi_uint mm,
|
|
mbedtls_mpi_uint *T )
|
|
{
|
|
memset( T, 0, (2*n+1)*ciL );
|
|
|
|
for( size_t i = 0; i < n; i++, T++ )
|
|
{
|
|
mbedtls_mpi_uint u0, u1;
|
|
/* T = (T + u0*B + u1*N) / 2^biL */
|
|
u0 = A[i];
|
|
u1 = ( T[0] + u0 * B[0] ) * mm;
|
|
|
|
(void) MPI_CORE(mla)( T, n + 2, B, B_len, u0 );
|
|
(void) MPI_CORE(mla)( T, n + 2, N, n, u1 );
|
|
}
|
|
|
|
mbedtls_mpi_uint carry, borrow, fixup;
|
|
|
|
carry = T[n];
|
|
borrow = MPI_CORE(sub)( X, T, N, n );
|
|
fixup = carry < borrow;
|
|
(void) MPI_CORE(add_if)( X, N, n, fixup );
|
|
}
|
|
|
|
mbedtls_mpi_uint MPI_CORE(mla)( mbedtls_mpi_uint *d, size_t d_len,
|
|
const mbedtls_mpi_uint *s, size_t s_len,
|
|
mbedtls_mpi_uint b )
|
|
{
|
|
mbedtls_mpi_uint c = 0; /* carry */
|
|
if( d_len < s_len )
|
|
s_len = d_len;
|
|
size_t excess_len = d_len - s_len;
|
|
size_t steps_x8 = s_len / 8;
|
|
size_t steps_x1 = s_len & 7;
|
|
|
|
while( steps_x8-- )
|
|
{
|
|
MULADDC_X8_INIT
|
|
MULADDC_X8_CORE
|
|
MULADDC_X8_STOP
|
|
}
|
|
|
|
while( steps_x1-- )
|
|
{
|
|
MULADDC_X1_INIT
|
|
MULADDC_X1_CORE
|
|
MULADDC_X1_STOP
|
|
}
|
|
|
|
while( excess_len-- )
|
|
{
|
|
*d += c; c = ( *d < c ); d++;
|
|
}
|
|
|
|
return( c );
|
|
}
|
|
|
|
mbedtls_mpi_uint MPI_CORE(sub)( mbedtls_mpi_uint *d,
|
|
const mbedtls_mpi_uint *l,
|
|
const mbedtls_mpi_uint *r,
|
|
size_t n )
|
|
{
|
|
mbedtls_mpi_uint c = 0, t, z;
|
|
|
|
for( size_t i = 0; i < n; i++ )
|
|
{
|
|
z = ( l[i] < c ); t = l[i] - c;
|
|
c = ( t < r[i] ) + z; d[i] = t - r[i];
|
|
}
|
|
|
|
return( c );
|
|
}
|
|
|
|
mbedtls_mpi_uint MPI_CORE(add_if)( mbedtls_mpi_uint *d,
|
|
const mbedtls_mpi_uint *r,
|
|
size_t n,
|
|
unsigned cond )
|
|
{
|
|
mbedtls_mpi_uint c = 0, t;
|
|
for( size_t i = 0; i < n; i++ )
|
|
{
|
|
mbedtls_mpi_uint add = cond * r[i];
|
|
t = c;
|
|
t += d[i]; c = ( t < d[i] );
|
|
t += add; c += ( t < add );
|
|
d[i] = t;
|
|
}
|
|
return( c );
|
|
}
|
|
|
|
#endif /* MBEDTLS_BIGNUM_C */
|