Reorganisation of the source tree

[ghc-hetmet.git] / rts / gmp / mpz / mul_2exp.c

diff --git a/rts/gmp/mpz/mul_2exp.c b/rts/gmp/mpz/mul_2exp.c
new file mode 100644 (file)
index 0000000..abea5fe
--- /dev/null
+++ b/rts/gmp/mpz/mul_2exp.c
@@ -0,0 +1,76 @@
+/* mpz_mul_2exp -- Multiply a bignum by 2**CNT
+
+Copyright (C) 1991, 1993, 1994, 1996 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 Lesser General Public License as published by
+the Free Software Foundation; either version 2.1 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 Lesser General Public
+License for more details.
+
+You should have received a copy of the GNU Lesser 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_mul_2exp (mpz_ptr w, mpz_srcptr u, unsigned long int cnt)
+#else
+mpz_mul_2exp (w, u, cnt)
+     mpz_ptr w;
+     mpz_srcptr u;
+     unsigned long int cnt;
+#endif
+{
+  mp_size_t usize = u->_mp_size;
+  mp_size_t abs_usize = ABS (usize);
+  mp_size_t wsize;
+  mp_size_t limb_cnt;
+  mp_ptr wp;
+  mp_limb_t wlimb;
+
+  if (usize == 0)
+    {
+      w->_mp_size = 0;
+      return;
+    }
+
+  limb_cnt = cnt / BITS_PER_MP_LIMB;
+  wsize = abs_usize + limb_cnt + 1;
+  if (w->_mp_alloc < wsize)
+    _mpz_realloc (w, wsize);
+
+  wp = w->_mp_d;
+  wsize = abs_usize + limb_cnt;
+
+  cnt %= BITS_PER_MP_LIMB;
+  if (cnt != 0)
+    {
+      wlimb = mpn_lshift (wp + limb_cnt, u->_mp_d, abs_usize, cnt);
+      if (wlimb != 0)
+       {
+         wp[wsize] = wlimb;
+         wsize++;
+       }
+    }
+  else
+    {
+      MPN_COPY_DECR (wp + limb_cnt, u->_mp_d, abs_usize);
+    }
+
+  /* Zero all whole limbs at low end.  Do it here and not before calling
+     mpn_lshift, not to lose for U == W.  */
+  MPN_ZERO (wp, limb_cnt);
+
+  w->_mp_size = usize >= 0 ? wsize : -wsize;
+}