Index: mpi-1.8.6/mpi.c
===================================================================
--- mpi-1.8.6.orig/mpi.c	2015-02-07 19:32:53.524604501 -0800
+++ mpi-1.8.6/mpi.c	2015-02-07 19:32:56.016560235 -0800
@@ -571,6 +571,15 @@
   return MP_OKAY;
 }
 
+mp_err mp_set_word(mp_int *mp, mp_word w, int sign)
+{
+  USED(mp) = 2;
+  DIGIT(mp, 0) = w & MP_DIGIT_MAX;
+  DIGIT(mp, 1) = w >> MP_DIGIT_BIT;
+  SIGN(mp) = sign;
+  return MP_OKAY;
+}
+
 /*------------------------------------------------------------------------*/
 /* {{{ Digit arithmetic */
 
Index: mpi-1.8.6/mpi.h
===================================================================
--- mpi-1.8.6.orig/mpi.h	2015-02-07 19:32:48.892686392 -0800
+++ mpi-1.8.6/mpi.h	2015-02-07 19:32:56.016560235 -0800
@@ -100,6 +100,7 @@
 mp_err mp_set_int(mp_int *mp, long z);
 mp_err mp_set_intptr(mp_int *mp, int_ptr_t z);
 mp_err mp_get_intptr(mp_int *mp, int_ptr_t *z);
+mp_err mp_set_word(mp_int *mp, mp_word w, int sign);
 
 /*------------------------------------------------------------------------*/
 /* Single digit arithmetic                                                */