Add the new modulus and the residue structures
Signed-off-by: Gabor Mezei <gabor.mezei@arm.com>
diff --git a/library/bignum_mod.h b/library/bignum_mod.h
new file mode 100644
index 0000000..378c58d
--- /dev/null
+++ b/library/bignum_mod.h
@@ -0,0 +1,68 @@
+/**
+ * Internal bignum functions
+ *
+ * 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.
+ */
+
+#ifndef MBEDTLS_BIGNUM_MOD_H
+#define MBEDTLS_BIGNUM_MOD_H
+
+#include "common.h"
+
+#if defined(MBEDTLS_BIGNUM_C)
+#include "mbedtls/bignum.h"
+#endif
+
+
+typedef struct
+{
+ size_t n;
+ mbedtls_mpi_uint *p;
+} mbedtls_mpi_mod_residue;
+
+typedef void* mbedtls_mpi_mont_struct;
+typedef void* mbedtls_mpi_opt_red_struct;
+
+typedef struct {
+ mbedtls_mpi_uint *p;
+ size_t n; // number of limbs
+ size_t plen; // bitlen of p
+ int ext_rep; // signals external representation (eg. byte order)
+ int int_rep; // selector to signal the active member of the union
+ union rep
+ {
+ mbedtls_mpi_mont_struct mont;
+ mbedtls_mpi_opt_red_struct ored;
+ } rep;
+} mbedtls_mpi_mod_modulus;
+
+void mbedtls_mpi_mod_residue_release( mbedtls_mpi_mod_residue *r );
+
+int mbedtls_mpi_mod_residue_setup( mbedtls_mpi_mod_residue *r,
+ mbedtls_mpi_mod_modulus *m,
+ mbedtls_mpi_uint *p );
+
+void mbedtls_mpi_mod_modulus_init( mbedtls_mpi_mod_modulus *m );
+
+void mbedtls_mpi_mod_modulus_init( mbedtls_mpi_mod_modulus *m );
+
+int mbedtls_mpi_mod_modulus_setup( mbedtls_mpi_mod_modulus *m,
+ mbedtls_mpi_uint *p,
+ size_t n,
+ int ext_rep,
+ int int_rep );
+
+#endif /* MBEDTLS_BIGNUM_MOD_H */
diff --git a/library/bignum_new.c b/library/bignum_new.c
new file mode 100644
index 0000000..3292861
--- /dev/null
+++ b/library/bignum_new.c
@@ -0,0 +1,138 @@
+/**
+ * Internal bignum functions
+ *
+ * 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/error.h"
+#include "mbedtls/bignum.h"
+#include "bignum_mod.h"
+
+#define ciL (sizeof(mbedtls_mpi_uint)) /* chars in limb */
+#define biL (ciL << 3) /* bits in limb */
+#define biH (ciL << 2) /* half limb size */
+
+/*
+ * Convert between bits/chars and number of limbs
+ * Divide first in order to avoid potential overflows
+ */
+#define BITS_TO_LIMBS(i) ( (i) / biL + ( (i) % biL != 0 ) )
+#define CHARS_TO_LIMBS(i) ( (i) / ciL + ( (i) % ciL != 0 ) )
+
+/*
+ * Count leading zero bits in a given integer
+ */
+static size_t mpi_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
+ */
+static size_t mpi_bitlen( const mbedtls_mpi_uint *X, size_t nx )
+{
+ size_t i, j;
+
+ if( nx == 0 )
+ return( 0 );
+
+ for( i = nx - 1; i > 0; i-- )
+ if( X[i] != 0 )
+ break;
+
+ j = biL - mpi_clz( X[i] );
+
+ return( ( i * biL ) + j );
+}
+
+void mbedtls_mpi_mod_residue_release( mbedtls_mpi_mod_residue *r )
+{
+ if ( r == NULL )
+ return;
+
+ r->n = 0;
+ r->p = NULL;
+}
+
+int mbedtls_mpi_mod_residue_setup( mbedtls_mpi_mod_residue *r,
+ mbedtls_mpi_mod_modulus *m,
+ mbedtls_mpi_uint *X )
+{
+ if( X == NULL || m == NULL || r == NULL || X >= m->p)
+ return( MBEDTLS_ERR_MPI_BAD_INPUT_DATA );
+
+ r->n = m->n;
+ r->p = X;
+
+ return( 0 );
+}
+
+void mbedtls_mpi_mod_modulus_init( mbedtls_mpi_mod_modulus *m )
+{
+ if ( m == NULL )
+ return;
+
+ m->rep.mont = 0;
+}
+
+void mbedtls_mpi_mod_modulus_free( mbedtls_mpi_mod_modulus *m )
+{
+ if ( m == NULL )
+ return;
+
+ m->p = NULL;
+ m->n = 0;
+ m->plen = 0;
+ m->ext_rep = 0;
+ m->int_rep = 0;
+ m->rep.mont = NULL;
+ m->rep.ored = NULL;
+}
+
+int mbedtls_mpi_mod_modulus_setup( mbedtls_mpi_mod_modulus *m,
+ mbedtls_mpi_uint *X,
+ size_t nx,
+ int ext_rep,
+ int int_rep )
+{
+ if ( X == NULL || m == NULL )
+ return( MBEDTLS_ERR_MPI_BAD_INPUT_DATA );
+
+ m->p = X;
+ m->n = nx;
+ m->ext_rep = ext_rep;
+ m->int_rep = int_rep;
+ m->plen = mpi_bitlen( X, nx );
+
+ return( 0 );
+}
+
+#endif /* MBEDTLS_BIGNUM_C */