Add docs for mbedtls_ct_memcmp_partial test
Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
diff --git a/tests/suites/test_suite_constant_time.function b/tests/suites/test_suite_constant_time.function
index 9df9432..262f841 100644
--- a/tests/suites/test_suite_constant_time.function
+++ b/tests/suites/test_suite_constant_time.function
@@ -260,6 +260,17 @@
/* END_CASE */
/* BEGIN_CASE depends_on:MBEDTLS_NIST_KW_C */
+
+/**
+ * Generate two arrays of the given size, and test mbedtls_ct_memcmp_partial
+ * over them. The arrays will be identical, except that one byte may be specified
+ * to be different.
+ *
+ * \p diff Index of byte that differs (if out of range, the arrays will match).
+ * \p size Size of arrays to compare
+ * \p skip_head Leading bytes to skip, as per mbedtls_ct_memcmp_partial
+ * \p skip_tail Trailing bytes to skip, as per mbedtls_ct_memcmp_partial
+ */
void mbedtls_ct_memcmp_partial(int diff, int size, int skip_head, int skip_tail)
{
uint8_t *a = NULL, *b = NULL;