Initial revision

1 files changed, 79 insertions, 0 deletions

diff --git a/mpz/tdiv_r_2exp.c b/mpz/tdiv_r_2exp.c
new file mode 100644
index 000000000..99d617e9f
--- /dev/null
+++ b/mpz/tdiv_r_2exp.c
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+/* mpz_tdiv_r_2exp -- Divide a integer by 2**CNT and produce a remainder.
+
+Copyright (C) 1991, 1993, 1994, 1995 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 Library General Public License as published by
+the Free Software Foundation; either version 2 of the License, 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 Library General Public
+License for more details.
+
+You should have received a copy of the GNU Library General Public License
+along with the GNU MP Library; see the file COPYING.LIB.  If not, write to
+the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+MA 02111-1307, USA. */
+
+#include "gmp.h"
+#include "gmp-impl.h"
+
+void
+#if __STDC__
+mpz_tdiv_r_2exp (mpz_ptr res, mpz_srcptr in, unsigned long int cnt)
+#else
+mpz_tdiv_r_2exp (res, in, cnt)
+     mpz_ptr res;
+     mpz_srcptr in;
+     unsigned long int cnt;
+#endif
+{
+  mp_size_t in_size = ABS (in->_mp_size);
+  mp_size_t res_size;
+  mp_size_t limb_cnt = cnt / BITS_PER_MP_LIMB;
+  mp_srcptr in_ptr = in->_mp_d;
+
+  if (in_size > limb_cnt)
+    {
+      /* The input operand is (probably) greater than 2**CNT.  */
+      mp_limb_t x;
+
+      x = in_ptr[limb_cnt] & (((mp_limb_t) 1 << cnt % BITS_PER_MP_LIMB) - 1);
+      if (x != 0)
+	{
+	  res_size = limb_cnt + 1;
+	  if (res->_mp_alloc < res_size)
+	    _mpz_realloc (res, res_size);
+
+	  res->_mp_d[limb_cnt] = x;
+	}
+      else
+	{
+	  res_size = limb_cnt;
+	  MPN_NORMALIZE (in_ptr, res_size);
+
+	  if (res->_mp_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->_mp_alloc < res_size)
+	_mpz_realloc (res, res_size);
+
+      limb_cnt = res_size;
+    }
+
+  if (res != in)
+    MPN_COPY (res->_mp_d, in->_mp_d, limb_cnt);
+  res->_mp_size = in->_mp_size >= 0 ? res_size : -res_size;
+}