1 files changed, 61 insertions, 0 deletions
diff --git a/third_party/heimdal/lib/hcrypto/libtommath/bn_mp_mul_d.c b/third_party/heimdal/lib/hcrypto/libtommath/bn_mp_mul_d.c
new file mode 100644
index 00000000000..b56dfa3c9db
--- /dev/null
+++ b/third_party/heimdal/lib/hcrypto/libtommath/bn_mp_mul_d.c
@@ -0,0 +1,61 @@
+#include "tommath_private.h"
+#ifdef BN_MP_MUL_D_C
+/* LibTomMath, multiple-precision integer library -- Tom St Denis */
+/* SPDX-License-Identifier: Unlicense */
+
+/* multiply by a digit */
+mp_err mp_mul_d(const mp_int *a, mp_digit b, mp_int *c)
+{
+   mp_digit u, *tmpa, *tmpc;
+   mp_word  r;
+   mp_err   err;
+   int      ix, olduse;
+
+   /* make sure c is big enough to hold a*b */
+   if (c->alloc < (a->used + 1)) {
+      if ((err = mp_grow(c, a->used + 1)) != MP_OKAY) {
+         return err;
+      }
+   }
+
+   /* get the original destinations used count */
+   olduse = c->used;
+
+   /* set the sign */
+   c->sign = a->sign;
+
+   /* alias for a->dp [source] */
+   tmpa = a->dp;
+
+   /* alias for c->dp [dest] */
+   tmpc = c->dp;
+
+   /* zero carry */
+   u = 0;
+
+   /* compute columns */
+   for (ix = 0; ix < a->used; ix++) {
+      /* compute product and carry sum for this term */
+      r       = (mp_word)u + ((mp_word)*tmpa++ * (mp_word)b);
+
+      /* mask off higher bits to get a single digit */
+      *tmpc++ = (mp_digit)(r & (mp_word)MP_MASK);
+
+      /* send carry into next iteration */
+      u       = (mp_digit)(r >> (mp_word)MP_DIGIT_BIT);
+   }
+
+   /* store final carry [if any] and increment ix offset  */
+   *tmpc++ = u;
+   ++ix;
+
+   /* now zero digits above the top */
+   MP_ZERO_DIGITS(tmpc, olduse - ix);
+
+   /* set used count */
+   c->used = a->used + 1;
+   mp_clamp(c);
+
+   return MP_OKAY;
+}
+#endif