1 files changed, 56 insertions, 0 deletions
diff --git a/third_party/heimdal/lib/hcrypto/libtommath/bn_mp_xor.c b/third_party/heimdal/lib/hcrypto/libtommath/bn_mp_xor.c
new file mode 100644
index 0000000..71e7ca1
--- /dev/null
+++ b/third_party/heimdal/lib/hcrypto/libtommath/bn_mp_xor.c
@@ -0,0 +1,56 @@
+#include "tommath_private.h"
+#ifdef BN_MP_XOR_C
+/* LibTomMath, multiple-precision integer library -- Tom St Denis */
+/* SPDX-License-Identifier: Unlicense */
+
+/* two complement xor */
+mp_err mp_xor(const mp_int *a, const mp_int *b, mp_int *c)
+{
+   int used = MP_MAX(a->used, b->used) + 1, i;
+   mp_err err;
+   mp_digit ac = 1, bc = 1, cc = 1;
+   mp_sign csign = (a->sign != b->sign) ? MP_NEG : MP_ZPOS;
+
+   if (c->alloc < used) {
+      if ((err = mp_grow(c, used)) != MP_OKAY) {
+         return err;
+      }
+   }
+
+   for (i = 0; i < used; i++) {
+      mp_digit x, y;
+
+      /* convert to two complement if negative */
+      if (a->sign == MP_NEG) {
+         ac += (i >= a->used) ? MP_MASK : (~a->dp[i] & MP_MASK);
+         x = ac & MP_MASK;
+         ac >>= MP_DIGIT_BIT;
+      } else {
+         x = (i >= a->used) ? 0uL : a->dp[i];
+      }
+
+      /* convert to two complement if negative */
+      if (b->sign == MP_NEG) {
+         bc += (i >= b->used) ? MP_MASK : (~b->dp[i] & MP_MASK);
+         y = bc & MP_MASK;
+         bc >>= MP_DIGIT_BIT;
+      } else {
+         y = (i >= b->used) ? 0uL : b->dp[i];
+      }
+
+      c->dp[i] = x ^ y;
+
+      /* convert to to sign-magnitude if negative */
+      if (csign == MP_NEG) {
+         cc += ~c->dp[i] & MP_MASK;
+         c->dp[i] = cc & MP_MASK;
+         cc >>= MP_DIGIT_BIT;
+      }
+   }
+
+   c->used = used;
+   c->sign = csign;
+   mp_clamp(c);
+   return MP_OKAY;
+}
+#endif