Bignum: Implement mbedtls_mpi_mod_raw_inv_prime() and tests

Fixes #6023.

Signed-off-by: Tom Cosgrove <tom.cosgrove@arm.com>

scripts/mbedtls_dev/bignum_mod_raw.py

@@ -18,6 +18,7 @@ from typing import Dict, List
 
 from . import test_data_generation
 from . import bignum_common
+from .bignum_data import ONLY_PRIME_MODULI
 
 class BignumModRawTarget(test_data_generation.BaseTarget):
     #pylint: disable=abstract-method, too-few-public-methods
@@ -53,6 +54,36 @@ class BignumModRawSub(bignum_common.ModOperationCommon,
 
 # BEGIN MERGE SLOT 3
 
+class BignumModRawInvPrime(bignum_common.ModOperationCommon,
+                           BignumModRawTarget):
+    """Test cases for bignum mpi_mod_raw_inv_prime()."""
+    moduli = ONLY_PRIME_MODULI
+    symbol = "^ -1"
+    test_function = "mpi_mod_raw_inv_prime"
+    test_name = "mbedtls_mpi_mod_raw_inv_prime (Montgomery form only)"
+    input_style = "fixed"
+    arity = 1
+    suffix = True
+
+    @property
+    def is_valid(self) -> bool:
+        return self.int_a > 0 and self.int_a < self.int_n
+
+    def arguments(self) -> List[str]:
+        # Input has to be given in Montgomery form
+        mont_a = self.to_montgomery(self.int_a)
+        arg_mont_a = self.format_arg('{:x}'.format(mont_a))
+        return [bignum_common.quote_str(n) for n in [self.arg_n,
+                                                     arg_mont_a]
+               ] + self.result()
+
+    def result(self) -> List[str]:
+        result = bignum_common.invmod(self.int_a, self.int_n)
+        if result < 0:
+            result += self.int_n
+        mont_result = self.to_montgomery(result)
+        return [self.format_result(mont_result)]
+
 # END MERGE SLOT 3
 
 # BEGIN MERGE SLOT 4