fix MP_MIN_PREC

libtom · Nov 3, 2019 · f27db36 · f27db36
1 parent f6e1152
commit f27db36
Showing 1 changed file with 6 additions and 2 deletions.
diff --git a/tommath_private.h b/tommath_private.h
@@ -177,9 +177,13 @@ MP_STATIC_ASSERT(correct_word_size, sizeof(mp_word) == (2u * sizeof(mp_digit)))
 #   endif
 #endif
 
-/* Minimum number of available digits in mp_int, MP_PREC >= MP_MIN_PREC */
-#define MP_MIN_PREC ((((int)MP_SIZEOF_BITS(long long) + MP_DIGIT_BIT) - 1) / MP_DIGIT_BIT)
+/* Minimum number of available digits in mp_int, MP_PREC >= MP_MIN_PREC
+ * - Must be at least 3 for s_mp_div_school.
+ * - Must be large enough such that uint64_t can be stored in mp_int without growing
+ */
+#define MP_MIN_PREC  3
 
+MP_STATIC_ASSERT(min_prec_large_enough, MP_MIN_PREC >= (((int)MP_SIZEOF_BITS(long long) + MP_DIGIT_BIT) - 1) / MP_DIGIT_BIT);
 MP_STATIC_ASSERT(prec_geq_min_prec, MP_PREC >= MP_MIN_PREC)
 
 /* random number source */