1 files changed, 89 insertions, 0 deletions
diff --git a/third_party/heimdal/lib/hcrypto/libtommath/bn_mp_add_d.c b/third_party/heimdal/lib/hcrypto/libtommath/bn_mp_add_d.c
new file mode 100644
index 0000000..f301575
--- /dev/null
+++ b/third_party/heimdal/lib/hcrypto/libtommath/bn_mp_add_d.c
@@ -0,0 +1,89 @@
+#include "tommath_private.h"
+#ifdef BN_MP_ADD_D_C
+/* LibTomMath, multiple-precision integer library -- Tom St Denis */
+/* SPDX-License-Identifier: Unlicense */
+
+/* single digit addition */
+mp_err mp_add_d(const mp_int *a, mp_digit b, mp_int *c)
+{
+   mp_err     err;
+   int ix, oldused;
+   mp_digit *tmpa, *tmpc;
+
+   /* grow c as required */
+   if (c->alloc < (a->used + 1)) {
+      if ((err = mp_grow(c, a->used + 1)) != MP_OKAY) {
+         return err;
+      }
+   }
+
+   /* if a is negative and |a| >= b, call c = |a| - b */
+   if ((a->sign == MP_NEG) && ((a->used > 1) || (a->dp[0] >= b))) {
+      mp_int a_ = *a;
+      /* temporarily fix sign of a */
+      a_.sign = MP_ZPOS;
+
+      /* c = |a| - b */
+      err = mp_sub_d(&a_, b, c);
+
+      /* fix sign  */
+      c->sign = MP_NEG;
+
+      /* clamp */
+      mp_clamp(c);
+
+      return err;
+   }
+
+   /* old number of used digits in c */
+   oldused = c->used;
+
+   /* source alias */
+   tmpa    = a->dp;
+
+   /* destination alias */
+   tmpc    = c->dp;
+
+   /* if a is positive */
+   if (a->sign == MP_ZPOS) {
+      /* add digits, mu is carry */
+      mp_digit mu = b;
+      for (ix = 0; ix < a->used; ix++) {
+         *tmpc   = *tmpa++ + mu;
+         mu      = *tmpc >> MP_DIGIT_BIT;
+         *tmpc++ &= MP_MASK;
+      }
+      /* set final carry */
+      ix++;
+      *tmpc++  = mu;
+
+      /* setup size */
+      c->used = a->used + 1;
+   } else {
+      /* a was negative and |a| < b */
+      c->used  = 1;
+
+      /* the result is a single digit */
+      if (a->used == 1) {
+         *tmpc++  =  b - a->dp[0];
+      } else {
+         *tmpc++  =  b;
+      }
+
+      /* setup count so the clearing of oldused
+       * can fall through correctly
+       */
+      ix       = 1;
+   }
+
+   /* sign always positive */
+   c->sign = MP_ZPOS;
+
+   /* now zero to oldused */
+   MP_ZERO_DIGITS(tmpc, oldused - ix);
+   mp_clamp(c);
+
+   return MP_OKAY;
+}
+
+#endif