Reorganisation of the source tree

Most of the other users of the fptools build system have migrated to
Cabal, and with the move to darcs we can now flatten the source tree
without losing history, so here goes.

The main change is that the ghc/ subdir is gone, and most of what it
contained is now at the top level.  The build system now makes no
pretense at being multi-project, it is just the GHC build system.

No doubt this will break many things, and there will be a period of
instability while we fix the dependencies.  A straightforward build
should work, but I haven't yet fixed binary/source distributions.
Changes to the Building Guide will follow, too.

1 files changed, 165 insertions, 0 deletions

diff --git a/rts/gmp/mpz/fib_ui.c b/rts/gmp/mpz/fib_ui.c
new file mode 100644
index 0000000000..4bebb80d94
--- /dev/null
+++ b/rts/gmp/mpz/fib_ui.c
@@ -0,0 +1,165 @@
+/* mpz_fib_ui(result, n) -- Set RESULT to the Nth Fibonacci number.
+
+Copyright (C) 1998, 1999, 2000 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"
+
+/* This is fast, but could be made somewhat faster and neater.
+   The timing is somewhat fluctuating for even/odd sizes because
+   of the extra hair used to save variables and operations.  Here
+   are a few things one might want to address:
+     1. Avoid using 4 intermediate variables in mpz_fib_bigcase.
+     2. Call mpn functions directly.  Straightforward for these functions.
+     3. Merge the three functions into one.
+
+Said by Kevin:
+   Consider using the Lucas numbers L[n] as an auxiliary sequence, making
+   it possible to do the "doubling" operation in mpz_fib_bigcase with two
+   squares rather than two multiplies.  The formulas are a little more
+   complicated, something like the following (untested).
+
+       F[2n] = ((F[n]+L[n])^2 - 6*F[n]^2 - 4*(-1)^n) / 2
+       L[2n] = 5*F[n]^2 + 2*(-1)^n
+
+       F[2n+1] = (F[2n] + L[2n]) / 2
+       L[2n+1] = (5*F[2n] + L[2n]) / 2
+
+   The Lucas number that comes for free here could even be returned.
+
+   Maybe there's formulas with two squares using just F[n], but I don't
+   know of any.
+*/
+
+/* Determine the needed storage for Fib(n).  */
+#define FIB_SIZE(n) (((mp_size_t) ((n)*0.695)) / BITS_PER_MP_LIMB + 2)
+
+static void mpz_fib_bigcase _PROTO ((mpz_t, mpz_t, unsigned long int));
+static void mpz_fib_basecase _PROTO ((mpz_t, mpz_t, unsigned long int));
+
+
+#ifndef FIB_THRESHOLD
+#define FIB_THRESHOLD 60
+#endif
+
+void
+#if __STDC__
+mpz_fib_ui (mpz_t r, unsigned long int n)
+#else
+mpz_fib_ui (r, n)
+     mpz_t r;
+     unsigned long int n;
+#endif
+{
+  if (n == 0)
+    mpz_set_ui (r, 0);
+  else
+    {
+      mpz_t t1;
+      mpz_init (t1);
+      if (n < FIB_THRESHOLD)
+	mpz_fib_basecase (t1, r, n);
+      else
+	mpz_fib_bigcase (t1, r, n);
+      mpz_clear (t1);
+    }
+}
+
+static void
+#if __STDC__
+mpz_fib_basecase (mpz_t t1, mpz_t t2, unsigned long int n)
+#else
+mpz_fib_basecase (t1, t2, n)
+     mpz_t t1;
+     mpz_t t2;
+     unsigned long int n;
+#endif
+{
+  unsigned long int m, i;
+
+  mpz_set_ui (t1, 0);
+  mpz_set_ui (t2, 1);
+  m = n/2;
+  for (i = 0; i < m; i++)
+    {
+      mpz_add (t1, t1, t2);
+      mpz_add (t2, t1, t2);
+    }
+  if ((n & 1) == 0)
+    {
+      mpz_sub (t1, t2, t1);
+      mpz_sub (t2, t2, t1);	/* trick: recover t1 value just overwritten */
+    }
+}
+
+static void
+#if __STDC__
+mpz_fib_bigcase (mpz_t t1, mpz_t t2, unsigned long int n)
+#else
+mpz_fib_bigcase (t1, t2, n)
+     mpz_t t1;
+     mpz_t t2;
+     unsigned long int n;
+#endif
+{
+  unsigned long int n2;
+  int ni, i;
+  mpz_t x1, x2, u1, u2;
+
+  ni = 0;
+  for (n2 = n; n2 >= FIB_THRESHOLD; n2 /= 2)
+    ni++;
+
+  mpz_fib_basecase (t1, t2, n2);
+
+  mpz_init (x1);
+  mpz_init (x2);
+  mpz_init (u1);
+  mpz_init (u2);
+
+  for (i = ni - 1; i >= 0; i--)
+    {
+      mpz_mul_2exp (x1, t1, 1);
+      mpz_mul_2exp (x2, t2, 1);
+
+      mpz_add (x1, x1, t2);
+      mpz_sub (x2, x2, t1);
+
+      mpz_mul (u1, t2, x1);
+      mpz_mul (u2, t1, x2);
+
+      if (((n >> i) & 1) == 0)
+	{
+	  mpz_sub (t1, u1, u2);
+	  mpz_set (t2, u1);
+	}
+      else
+	{
+	  mpz_set (t1, u1);
+	  mpz_mul_2exp (t2, u1, 1);
+	  mpz_sub (t2, t2, u2);
+	}
+    }
+
+  mpz_clear (x1);
+  mpz_clear (x2);
+  mpz_clear (u1);
+  mpz_clear (u2);
+}