GNU MP (Multiprecision) library. This is needed by secure RPC (being

done by Bill Paul) and various other BSD programs.
Obtained from:FSF

1 files changed, 82 insertions, 0 deletions

diff --git a/gnu/lib/libgmp/mpz_mod_2exp.c b/gnu/lib/libgmp/mpz_mod_2exp.c
new file mode 100644
index 0000000..696acd4
--- /dev/null
+++ b/gnu/lib/libgmp/mpz_mod_2exp.c
@@ -0,0 +1,82 @@
+/* mpz_mod_2exp -- divide a MP_INT by 2**n and produce a remainder.
+
+Copyright (C) 1991 Free Software Foundation, Inc.
+
+This file is part of the GNU MP Library.
+
+The GNU MP Library 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, or (at your option)
+any later version.
+
+The GNU MP Library 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 the GNU MP Library; see the file COPYING.  If not, write to
+the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
+
+#include "gmp.h"
+#include "gmp-impl.h"
+
+void
+#ifdef __STDC__
+mpz_mod_2exp (MP_INT *res, const MP_INT *in, unsigned long int cnt)
+#else
+mpz_mod_2exp (res, in, cnt)
+     MP_INT *res;
+     const MP_INT *in;
+     unsigned long int cnt;
+#endif
+{
+  mp_size in_size = ABS (in->size);
+  mp_size res_size;
+  mp_size limb_cnt = cnt / BITS_PER_MP_LIMB;
+  mp_srcptr in_ptr = in->d;
+
+  if (in_size > limb_cnt)
+    {
+      /* The input operand is (probably) greater than 2**CNT.  */
+      mp_limb x;
+
+      x = in_ptr[limb_cnt] & (((mp_limb) 1 << cnt % BITS_PER_MP_LIMB) - 1);
+      if (x != 0)
+	{
+	  res_size = limb_cnt + 1;
+	  if (res->alloc < res_size)
+	    _mpz_realloc (res, res_size);
+
+	  res->d[limb_cnt] = x;
+	}
+      else
+	{
+	  mp_size i;
+
+	  for (i = limb_cnt - 1; i >= 0; i--)
+	    if (in_ptr[i] != 0)
+	      break;
+	  res_size = i + 1;
+
+	  if (res->alloc < res_size)
+	    _mpz_realloc (res, res_size);
+
+	  limb_cnt = res_size;
+	}
+    }
+  else
+    {
+      /* The input operand is smaller than 2**CNT.  We perform a no-op,
+	 apart from that we might need to copy IN to RES.  */
+      res_size = in_size;
+      if (res->alloc < res_size)
+	_mpz_realloc (res, res_size);
+
+      limb_cnt = res_size;
+    }
+
+  if (res != in)
+    MPN_COPY (res->d, in->d, limb_cnt);
+  res->size = (in->size >= 0) ? res_size : -res_size;
+}