1 files changed, 68 insertions, 0 deletions
diff --git a/ghc/runtime/gmp/mpz_mul_2exp.c b/ghc/runtime/gmp/mpz_mul_2exp.c
new file mode 100644
index 0000000000..1a9767a9f7
--- /dev/null
+++ b/ghc/runtime/gmp/mpz_mul_2exp.c
@@ -0,0 +1,68 @@
+/* mpz_mul_2exp -- Multiply a bignum by 2**CNT
+
+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_mul_2exp (MP_INT *w, const MP_INT *u, unsigned long int cnt)
+#else
+mpz_mul_2exp (w, u, cnt)
+     MP_INT *w;
+     const MP_INT *u;
+     unsigned long int cnt;
+#endif
+{
+  mp_size usize = u->size;
+  mp_size abs_usize = ABS (usize);
+  mp_size wsize;
+  mp_size limb_cnt;
+  mp_ptr wp;
+  mp_limb wdigit;
+
+  if (usize == 0)
+    {
+      w->size = 0;
+      return;
+    }
+
+  limb_cnt = cnt / BITS_PER_MP_LIMB;
+  wsize = abs_usize + limb_cnt + 1;
+  if (w->alloc < wsize)
+    _mpz_realloc (w, wsize);
+  wp = w->d;
+
+  wdigit = mpn_lshift (wp + limb_cnt, u->d, abs_usize,
+			cnt % BITS_PER_MP_LIMB);
+  wsize = abs_usize + limb_cnt;
+
+  if (wdigit != 0)
+    {
+      wp[wsize] = wdigit;
+      wsize++;
+    }
+
+  /* Zero all whole digits at low end.  Do it here and not before calling
+     mpn_lshift, not to loose for U == W.  */
+  MPN_ZERO (wp, limb_cnt);
+
+  w->size = (usize >= 0) ? wsize : -wsize;
+}