diff libtommath/bn_mp_neg.c @ 330:5488db2e9e4e

merge of 332f709a4cb39cde4cedab7c3be89e05f3023067 and ca4ca78b82c5d430c69ce01bf794e8886ce81431
author Matt Johnston <matt@ucc.asn.au>
date Sat, 10 Jun 2006 16:39:40 +0000
parents eed26cff980b
children 5ff8218bcee9
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libtommath/bn_mp_neg.c	Sat Jun 10 16:39:40 2006 +0000
@@ -0,0 +1,36 @@
+#include <tommath.h>
+#ifdef BN_MP_NEG_C
+/* LibTomMath, multiple-precision integer library -- Tom St Denis
+ *
+ * LibTomMath is a library that provides multiple-precision
+ * integer arithmetic as well as number theoretic functionality.
+ *
+ * The library was designed directly after the MPI library by
+ * Michael Fromberger but has been written from scratch with
+ * additional optimizations in place.
+ *
+ * The library is free for all purposes without any express
+ * guarantee it works.
+ *
+ * Tom St Denis, [email protected], http://math.libtomcrypt.org
+ */
+
+/* b = -a */
+int mp_neg (mp_int * a, mp_int * b)
+{
+  int     res;
+  if (a != b) {
+     if ((res = mp_copy (a, b)) != MP_OKAY) {
+        return res;
+     }
+  }
+
+  if (mp_iszero(b) != MP_YES) {
+     b->sign = (a->sign == MP_ZPOS) ? MP_NEG : MP_ZPOS;
+  } else {
+     b->sign = MP_ZPOS;
+  }
+
+  return MP_OKAY;
+}
+#endif