diff --git a/tests/suites/test_suite_bignum_mod.function b/tests/suites/test_suite_bignum_mod.function
index 51a910f..6e25ff7 100644
--- a/tests/suites/test_suite_bignum_mod.function
+++ b/tests/suites/test_suite_bignum_mod.function
@@ -109,99 +109,89 @@
                   char * input_N,
                   char * result )
 {
-    mbedtls_mpi_uint *A = NULL;
-    mbedtls_mpi_uint *B = NULL;
-    mbedtls_mpi_uint *N = NULL;
     mbedtls_mpi_uint *X = NULL;
-    mbedtls_mpi_uint *R = NULL;
-    size_t limbs_A;
-    size_t limbs_B;
-    size_t limbs_N;
-    size_t limbs_R;
 
     mbedtls_mpi_mod_modulus m;
     mbedtls_mpi_mod_modulus_init( &m );
 
-    TEST_EQUAL( mbedtls_test_read_mpi_core( &A, &limbs_A, input_A ), 0 );
-    TEST_EQUAL( mbedtls_test_read_mpi_core( &B, &limbs_B, input_B ), 0 );
-    TEST_EQUAL( mbedtls_test_read_mpi_core( &N, &limbs_N, input_N ), 0 );
-    TEST_EQUAL( mbedtls_test_read_mpi_core( &R, &limbs_R, result  ), 0 );
-
-    const size_t limbs = limbs_N;
-    const size_t bytes = limbs * sizeof( mbedtls_mpi_uint );
-
-    TEST_EQUAL( limbs_A, limbs );
-    TEST_EQUAL( limbs_B, limbs );
-    TEST_EQUAL( limbs_R, limbs );
-
-    ASSERT_ALLOC( X, limbs );
-
-    TEST_EQUAL( mbedtls_mpi_mod_modulus_setup(
-                        &m, N, limbs,
-                        MBEDTLS_MPI_MOD_REP_MONTGOMERY ), 0 );
+    TEST_EQUAL( test_read_modulus( &m, MBEDTLS_MPI_MOD_REP_MONTGOMERY, input_N ),
+                0 );
 
     mbedtls_mpi_mod_residue rA;
-    TEST_EQUAL( mbedtls_mpi_mod_residue_setup( &rA, &m, A, limbs ), 0 );
+    TEST_EQUAL( test_read_residue( &rA, &m, input_A, 0 ), 0 );
 
     mbedtls_mpi_mod_residue rB;
-    TEST_EQUAL( mbedtls_mpi_mod_residue_setup( &rB, &m, B, limbs ), 0 );
+    TEST_EQUAL( test_read_residue( &rB, &m, input_B, 0 ), 0 );
+
+    mbedtls_mpi_mod_residue rR;
+    TEST_EQUAL( test_read_residue( &rR, &m, result, 0 ), 0 );
+
+    const size_t limbs = m.limbs;
+    const size_t bytes = limbs * sizeof( mbedtls_mpi_uint );
+
+    TEST_EQUAL( rA.limbs, limbs );
+    TEST_EQUAL( rB.limbs, limbs );
+    TEST_EQUAL( rR.limbs, limbs );
+
+    ASSERT_ALLOC( X, limbs );
 
     mbedtls_mpi_mod_residue rX;
     TEST_EQUAL( mbedtls_mpi_mod_residue_setup( &rX, &m, X, limbs ), 0 );
 
     TEST_EQUAL( mbedtls_mpi_mod_mul( &rX, &rA, &rB, &m ), 0 );
-    ASSERT_COMPARE( rX.p, bytes, R, bytes );
+    ASSERT_COMPARE( rX.p, bytes, rR.p, bytes );
 
     /* alias X to A */
     memcpy( rX.p, rA.p, bytes );
     TEST_EQUAL( mbedtls_mpi_mod_mul( &rX, &rX, &rB, &m ), 0 );
-    ASSERT_COMPARE( rX.p, bytes, R, bytes );
+    ASSERT_COMPARE( rX.p, bytes, rR.p, bytes );
 
     /* alias X to B */
     memcpy( rX.p, rB.p, bytes );
     TEST_EQUAL( mbedtls_mpi_mod_mul( &rX, &rA, &rX, &m ), 0);
-    ASSERT_COMPARE( rX.p, bytes, R, bytes );
+    ASSERT_COMPARE( rX.p, bytes, rR.p, bytes );
 
     /* A == B: alias A and B */
     if( memcmp( rA.p, rB.p, bytes ) == 0 )
     {
         TEST_EQUAL( mbedtls_mpi_mod_mul( &rX, &rA, &rA, &m ), 0 );
-        ASSERT_COMPARE( rX.p, bytes, R, bytes );
+        ASSERT_COMPARE( rX.p, bytes, rR.p, bytes );
 
         /* X, A, B all aliased together */
         memcpy( rX.p, rA.p, bytes );
         TEST_EQUAL( mbedtls_mpi_mod_mul( &rX, &rX, &rX, &m ), 0 );
-        ASSERT_COMPARE( rX.p, bytes, R, bytes );
+        ASSERT_COMPARE( rX.p, bytes, rR.p, bytes );
     }
 
     /* A != B: test B * A */
     else
     {
         TEST_EQUAL( mbedtls_mpi_mod_mul( &rX, &rB, &rA, &m ), 0 );
-        ASSERT_COMPARE( rX.p, bytes, R, bytes );
+        ASSERT_COMPARE( rX.p, bytes, rR.p, bytes );
 
         /* B * A: alias X to A */
         memcpy( rX.p, rA.p, bytes );
         TEST_EQUAL( mbedtls_mpi_mod_mul( &rX, &rB, &rX, &m ), 0 );
-        ASSERT_COMPARE( rX.p, bytes, R, bytes );
+        ASSERT_COMPARE( rX.p, bytes, rR.p, bytes );
 
         /* B + A: alias X to B */
         memcpy( rX.p, rB.p, bytes );
         TEST_EQUAL( mbedtls_mpi_mod_mul( &rX, &rX, &rA, &m ), 0 );
-        ASSERT_COMPARE( rX.p, bytes, R, bytes );
+        ASSERT_COMPARE( rX.p, bytes, rR.p, bytes );
     }
 
 exit:
     mbedtls_mpi_mod_residue_release( &rA );
     mbedtls_mpi_mod_residue_release( &rB );
+    mbedtls_mpi_mod_residue_release( &rR );
     mbedtls_mpi_mod_residue_release( &rX );
     mbedtls_mpi_mod_modulus_free( &m );
 
-    mbedtls_free( A );
-    mbedtls_free( B );
-    mbedtls_free( N );
+    mbedtls_free( rA.p );
+    mbedtls_free( rB.p );
+    mbedtls_free( rR.p );
     mbedtls_free( X );
-    mbedtls_free( R );
+    mbedtls_free( (mbedtls_mpi_uint *) m.p );
 }
 /* END_CASE */
 
@@ -212,51 +202,36 @@
                       char * result,
                       int exp_ret )
 {
-    mbedtls_mpi_uint *A = NULL;
-    mbedtls_mpi_uint *B = NULL;
-    mbedtls_mpi_uint *N = NULL;
     mbedtls_mpi_uint *X = NULL;
-    mbedtls_mpi_uint *R = NULL;
-    size_t limbs_A = 0;
-    size_t limbs_B = 0;
-    size_t limbs_N = 0;
-    size_t limbs_X = 0;
 
     mbedtls_mpi_mod_modulus m;
     mbedtls_mpi_mod_modulus_init( &m );
 
-    mbedtls_mpi_mod_modulus fake_m;
-    mbedtls_mpi_mod_modulus_init( &fake_m );
-
-    TEST_EQUAL( mbedtls_test_read_mpi_core( &A, &limbs_A, input_A ), 0 );
-    TEST_EQUAL( mbedtls_test_read_mpi_core( &B, &limbs_B, input_B ), 0 );
-    TEST_EQUAL( mbedtls_test_read_mpi_core( &N, &limbs_N, input_N ), 0 );
-    TEST_EQUAL( mbedtls_test_read_mpi_core( &R, &limbs_X, result  ), 0 );
-
-    ASSERT_ALLOC( X, limbs_X );
-
-    TEST_EQUAL( mbedtls_mpi_mod_modulus_setup(
-                    &m, N, limbs_N,
-                    MBEDTLS_MPI_MOD_REP_MONTGOMERY ), 0 );
+    TEST_EQUAL( test_read_modulus( &m, MBEDTLS_MPI_MOD_REP_MONTGOMERY, input_N ),
+                0 );
 
     mbedtls_mpi_mod_residue rA;
-    TEST_EQUAL( mbedtls_mpi_mod_residue_setup( &rA, &m, A, limbs_N ), 0 );
-    rA.limbs = limbs_A;
+    TEST_EQUAL( test_read_residue( &rA, &m, input_A, 1 ), 0 );
 
     mbedtls_mpi_mod_residue rB;
-    TEST_EQUAL( mbedtls_mpi_mod_residue_setup( &rB, &m, B, limbs_N ), 0 );
-    rB.limbs = limbs_B;
+    TEST_EQUAL( test_read_residue( &rB, &m, input_B, 1 ), 0 );
+
+    mbedtls_mpi_mod_residue rR;
+    TEST_EQUAL( test_read_residue( &rR, &m, result, 1 ), 0 );
+
+    const size_t limbs = m.limbs;
+
+    ASSERT_ALLOC( X, limbs );
 
     mbedtls_mpi_mod_residue rX;
-    TEST_EQUAL( mbedtls_mpi_mod_residue_setup( &rX, &m, X, limbs_N ), 0 );
-    rX.limbs = limbs_X;
-
-    /* Convert to Montgomery representation */
-    TEST_EQUAL( mbedtls_mpi_mod_raw_to_mont_rep( rA.p, &m ), 0 );
-    TEST_EQUAL( mbedtls_mpi_mod_raw_to_mont_rep( rB.p, &m ), 0 );
+    TEST_EQUAL( mbedtls_mpi_mod_residue_setup( &rX, &m, X, limbs ), 0 );
+    rX.limbs = rR.limbs;
 
     TEST_EQUAL( mbedtls_mpi_mod_mul( &rX, &rA, &rB, &m ), exp_ret );
 
+    mbedtls_mpi_mod_modulus fake_m;
+    mbedtls_mpi_mod_modulus_init( &fake_m );
+
     /* Check when m is not initialized */
     TEST_EQUAL( mbedtls_mpi_mod_mul( &rX, &rA, &rB, &fake_m ),
                 MBEDTLS_ERR_MPI_BAD_INPUT_DATA );
@@ -264,15 +239,16 @@
 exit:
     mbedtls_mpi_mod_residue_release( &rA );
     mbedtls_mpi_mod_residue_release( &rB );
+    mbedtls_mpi_mod_residue_release( &rR );
     mbedtls_mpi_mod_residue_release( &rX );
     mbedtls_mpi_mod_modulus_free( &m );
     mbedtls_mpi_mod_modulus_free( &fake_m );
 
-    mbedtls_free( A );
-    mbedtls_free( B );
-    mbedtls_free( N );
+    mbedtls_free( rA.p );
+    mbedtls_free( rB.p );
+    mbedtls_free( rR.p );
     mbedtls_free( X );
-    mbedtls_free( R );
+    mbedtls_free( (mbedtls_mpi_uint *) m.p );
 }
 /* END_CASE */