Fix bug in bignum addition.

* mpi/mpi.c (s_mp_add): It looks like this function had the
same kind of bug I fixed years ago in the multiplication routines.
("fix-mult-bug" patch, originally).  In the main loop, two digit-sized
values are added together to produce a partial sum with carry.
Unfortunately, both operands digit-sized, so the result is truncated to
the digit type. The cast of one of the operands to mp_word is missing.

1 files changed, 1 insertions, 1 deletions

diff --git a/mpi/mpi.c b/mpi/mpi.c
index 1e236e26..aea72585 100644
--- a/mpi/mpi.c
+++ b/mpi/mpi.c
@@ -4130,7 +4130,7 @@ mp_err   s_mp_add(mp_int *a, mp_int *b)        /* magnitude addition      */
   pa = DIGITS(a);
   pb = DIGITS(b);
   for(ix = 0; ix < used; ++ix) {
-    w += *pa + *pb++;
+    w += *pa + convert(mp_word, *pb++);
     *pa++ = ACCUM(w);
     w = CARRYOUT(w);
   }