Reuse Bignum helper functions
Signed-off-by: Janos Follath <janos.follath@arm.com>
diff --git a/library/bignum.c b/library/bignum.c
index 870365d..a238f8c 100644
--- a/library/bignum.c
+++ b/library/bignum.c
@@ -338,40 +338,11 @@
}
/*
- * Count leading zero bits in a given integer
- */
-static size_t mbedtls_clz( const mbedtls_mpi_uint x )
-{
- size_t j;
- mbedtls_mpi_uint mask = (mbedtls_mpi_uint) 1 << (biL - 1);
-
- for( j = 0; j < biL; j++ )
- {
- if( x & mask ) break;
-
- mask >>= 1;
- }
-
- return j;
-}
-
-/*
* Return the number of bits
*/
size_t mbedtls_mpi_bitlen( const mbedtls_mpi *X )
{
- size_t i, j;
-
- if( X->n == 0 )
- return( 0 );
-
- for( i = X->n - 1; i > 0; i-- )
- if( X->p[i] != 0 )
- break;
-
- j = biL - mbedtls_clz( X->p[i] );
-
- return( ( i * biL ) + j );
+ return mbedtls_mpi_core_bitlen( X->p, X->n );
}
/*
@@ -678,97 +649,6 @@
}
#endif /* MBEDTLS_FS_IO */
-
-/* Convert a big-endian byte array aligned to the size of mbedtls_mpi_uint
- * into the storage form used by mbedtls_mpi. */
-
-static mbedtls_mpi_uint mpi_uint_bigendian_to_host_c( mbedtls_mpi_uint x )
-{
- uint8_t i;
- unsigned char *x_ptr;
- mbedtls_mpi_uint tmp = 0;
-
- for( i = 0, x_ptr = (unsigned char*) &x; i < ciL; i++, x_ptr++ )
- {
- tmp <<= CHAR_BIT;
- tmp |= (mbedtls_mpi_uint) *x_ptr;
- }
-
- return( tmp );
-}
-
-static mbedtls_mpi_uint mpi_uint_bigendian_to_host( mbedtls_mpi_uint x )
-{
-#if defined(__BYTE_ORDER__)
-
-/* Nothing to do on bigendian systems. */
-#if ( __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__ )
- return( x );
-#endif /* __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__ */
-
-#if ( __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ )
-
-/* For GCC and Clang, have builtins for byte swapping. */
-#if defined(__GNUC__) && defined(__GNUC_PREREQ)
-#if __GNUC_PREREQ(4,3)
-#define have_bswap
-#endif
-#endif
-
-#if defined(__clang__) && defined(__has_builtin)
-#if __has_builtin(__builtin_bswap32) && \
- __has_builtin(__builtin_bswap64)
-#define have_bswap
-#endif
-#endif
-
-#if defined(have_bswap)
- /* The compiler is hopefully able to statically evaluate this! */
- switch( sizeof(mbedtls_mpi_uint) )
- {
- case 4:
- return( __builtin_bswap32(x) );
- case 8:
- return( __builtin_bswap64(x) );
- }
-#endif
-#endif /* __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ */
-#endif /* __BYTE_ORDER__ */
-
- /* Fall back to C-based reordering if we don't know the byte order
- * or we couldn't use a compiler-specific builtin. */
- return( mpi_uint_bigendian_to_host_c( x ) );
-}
-
-static void mpi_bigendian_to_host( mbedtls_mpi_uint * const p, size_t limbs )
-{
- mbedtls_mpi_uint *cur_limb_left;
- mbedtls_mpi_uint *cur_limb_right;
- if( limbs == 0 )
- return;
-
- /*
- * Traverse limbs and
- * - adapt byte-order in each limb
- * - swap the limbs themselves.
- * For that, simultaneously traverse the limbs from left to right
- * and from right to left, as long as the left index is not bigger
- * than the right index (it's not a problem if limbs is odd and the
- * indices coincide in the last iteration).
- */
- for( cur_limb_left = p, cur_limb_right = p + ( limbs - 1 );
- cur_limb_left <= cur_limb_right;
- cur_limb_left++, cur_limb_right-- )
- {
- mbedtls_mpi_uint tmp;
- /* Note that if cur_limb_left == cur_limb_right,
- * this code effectively swaps the bytes only once. */
- tmp = mpi_uint_bigendian_to_host( *cur_limb_left );
- *cur_limb_left = mpi_uint_bigendian_to_host( *cur_limb_right );
- *cur_limb_right = tmp;
- }
-}
-
/*
* Import X from unsigned binary data, little endian
*
@@ -824,7 +704,7 @@
Xp = (unsigned char*) X->p;
memcpy( Xp + overhead, buf, buflen );
- mpi_bigendian_to_host( X->p, limbs );
+ mbedtls_mpi_core_bigendian_to_host( X->p, limbs );
}
cleanup:
@@ -1530,7 +1410,7 @@
/*
* Normalize the divisor, d, and dividend, u0, u1
*/
- s = mbedtls_clz( d );
+ s = mbedtls_mpi_core_clz( d );
d = d << s;
u1 = u1 << s;
@@ -2319,7 +2199,7 @@
memset( X->p, 0, overhead );
memset( (unsigned char *) X->p + limbs * ciL, 0, ( X->n - limbs ) * ciL );
MBEDTLS_MPI_CHK( f_rng( p_rng, (unsigned char *) X->p + overhead, n_bytes ) );
- mpi_bigendian_to_host( X->p, limbs );
+ mbedtls_mpi_core_bigendian_to_host( X->p, limbs );
cleanup:
return( ret );