diff --git a/library/bignum_mod.c b/library/bignum_mod.c
index a4ed32b..6c13b4b 100644
--- a/library/bignum_mod.c
+++ b/library/bignum_mod.c
@@ -39,7 +39,7 @@
                                    mbedtls_mpi_uint *p,
                                    size_t p_limbs )
 {
-    if( p_limbs < m->limbs || !mbedtls_mpi_core_lt_ct( m->p, p, p_limbs ) )
+    if( p_limbs > m->limbs || !mbedtls_mpi_core_lt_ct( p, m->p, m->limbs ) )
         return( MBEDTLS_ERR_MPI_BAD_INPUT_DATA );
 
     r->limbs = m->limbs;
diff --git a/tests/suites/test_suite_bignum_mod.data b/tests/suites/test_suite_bignum_mod.data
index 6b25c49..5edb283 100644
--- a/tests/suites/test_suite_bignum_mod.data
+++ b/tests/suites/test_suite_bignum_mod.data
@@ -50,6 +50,9 @@
 # END MERGE SLOT 6
 
 # BEGIN MERGE SLOT 7
+Test mbedtls_mpi_residue_setup
+mpi_residue_setup:
+
 Test mbedtls_mpi_mod_io_neg
 mpi_mod_io_neg:
 
@@ -280,4 +283,3 @@
 
 Test mbedtls_mpi_mod_io #76 N: "32292747613635961694771916499883650667878589411552643628627186850993060141490368296439843252993342320145797691611646027435006878234727648863911408777308953382400333083852585109256846643097239747078406546553406955958288616728627292699264194880486908744773379992784153004816057528456043920098334713005039494478693892693017304730883448003944721685094014669042959451482141781404822386404101555113742346277194830729517252154824958327000717338180410404929239489607893939166712107274943411892079802406181464789204374234653633818543559183821503846194953493439237710780169796543565449952151334229364816621060143650318299210551" A: "136".
 mpi_mod_io:"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":"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":MBEDTLS_MPI_MOD_EXT_REP_LE
-
diff --git a/tests/suites/test_suite_bignum_mod.function b/tests/suites/test_suite_bignum_mod.function
index 00e8306..5a2d000 100644
--- a/tests/suites/test_suite_bignum_mod.function
+++ b/tests/suites/test_suite_bignum_mod.function
@@ -81,6 +81,53 @@
 
 /* BEGIN MERGE SLOT 7 */
 /* BEGIN_CASE */
+void mpi_residue_setup( )
+{
+    #define RS_ONE       0
+    #define RS_MAX_MIN1  1
+    #define RS_MAX       2
+    const char * s_data[ 3 ] = { "01", "fe", "ff" };
+
+    mbedtls_mpi_uint *N = NULL;
+    mbedtls_mpi_uint *R = NULL;
+    mbedtls_mpi_uint *R_MAX = NULL;
+    size_t n_limbs, r_limbs, r_max_limbs;
+    mbedtls_mpi_mod_modulus m;
+    mbedtls_mpi_mod_residue r;
+
+    /* Allocate the memory for intermediate data structures */
+    TEST_EQUAL( 0, mbedtls_test_read_mpi_core( &N, &n_limbs, s_data[ RS_MAX_MIN1 ] ) );
+    TEST_EQUAL( 0, mbedtls_test_read_mpi_core( &R, &r_limbs, s_data[ RS_ONE ] ) );
+    TEST_EQUAL( 0, mbedtls_test_read_mpi_core( &R_MAX, &r_max_limbs, s_data[ RS_MAX ] ) );
+
+    mbedtls_mpi_mod_modulus_init( &m );
+
+    TEST_EQUAL( 0, mbedtls_mpi_mod_modulus_setup( &m, N, n_limbs,
+                MBEDTLS_MPI_MOD_EXT_REP_LE, MBEDTLS_MPI_MOD_REP_MONTGOMERY ) );
+
+    TEST_EQUAL( 0, mbedtls_mpi_mod_residue_setup( &r, &m, R , r_limbs ) );
+
+    /* Test for r-> limbs > m-> limbs */
+    TEST_EQUAL( MBEDTLS_ERR_MPI_BAD_INPUT_DATA, mbedtls_mpi_mod_residue_setup( &r, &m, R , r_limbs + 1 ) );
+
+    /* Test for r-> p > m-> p */
+    TEST_EQUAL( MBEDTLS_ERR_MPI_BAD_INPUT_DATA, mbedtls_mpi_mod_residue_setup( &r, &m, R_MAX , r_max_limbs ) );
+
+    /* Test for r-> p == m-> p */
+    TEST_EQUAL( MBEDTLS_ERR_MPI_BAD_INPUT_DATA, mbedtls_mpi_mod_residue_setup( &r, &m, N , r_max_limbs ) );
+
+exit:
+    mbedtls_mpi_mod_modulus_free( &m );
+    mbedtls_free( N );
+    mbedtls_free( R );
+    mbedtls_free( R_MAX );
+
+    #undef RS_ONE
+    #undef RS_MAX_MIN1
+    #undef RS_MAX
+}
+/* END_CASE */
+/* BEGIN_CASE */
 void mpi_mod_io_neg( )
 {
     #define IO_ZERO        0