1 files changed, 56 insertions, 0 deletions

diff --git a/lib/mpi/mpi-bit.c b/lib/mpi/mpi-bit.c
new file mode 100644
index 000000000000..568724804f29
--- /dev/null
+++ b/lib/mpi/mpi-bit.c
@@ -0,0 +1,56 @@
+/* mpi-bit.c  -  MPI bit level fucntions
+ * Copyright (C) 1998, 1999 Free Software Foundation, Inc.
+ *
+ * This file is part of GnuPG.
+ *
+ * GnuPG is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * GnuPG is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ */
+
+#include "mpi-internal.h"
+#include "longlong.h"
+
+#define A_LIMB_1 ((mpi_limb_t) 1)
+
+/****************
+ * Sometimes we have MSL (most significant limbs) which are 0;
+ * this is for some reasons not good, so this function removes them.
+ */
+void mpi_normalize(MPI a)
+{
+        for (; a->nlimbs && !a->d[a->nlimbs - 1]; a->nlimbs--)
+                ;
+}
+
+/****************
+ * Return the number of bits in A.
+ */
+unsigned mpi_get_nbits(MPI a)
+{
+        unsigned n;
+
+        mpi_normalize(a);
+
+        if (a->nlimbs) {
+                mpi_limb_t alimb = a->d[a->nlimbs - 1];
+                if (alimb)
+                        count_leading_zeros(n, alimb);
+                else
+                        n = BITS_PER_MPI_LIMB;
+                n = BITS_PER_MPI_LIMB - n + (a->nlimbs - 1) * BITS_PER_MPI_LIMB;
+        } else
+                n = 0;
+        return n;
+}
+EXPORT_SYMBOL_GPL(mpi_get_nbits);