remove empty dir

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

diff --git a/ghc/rts/gmp/mpz/gcdext.c b/ghc/rts/gmp/mpz/gcdext.c
index adf66b0..3ba04c8 100644 (file)
--- a/ghc/rts/gmp/mpz/gcdext.c
+++ b/ghc/rts/gmp/mpz/gcdext.c
@@ -1,30 +1,30 @@
 /* mpz_gcdext(g, s, t, a, b) -- Set G to gcd(a, b), and S and T such that
    g = as + bt.
 
-Copyright (C) 1991, 1993, 1994, 1995 Free Software Foundation, Inc.
+Copyright (C) 1991, 1993, 1994, 1995, 1996, 1997, 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 Library General Public License as published by
-the Free Software Foundation; either version 2 of the License, or (at your
+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 Library General Public
+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 Library General Public License
+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 <stdio.h> /* for NULL */
 #include "gmp.h"
 #include "gmp-impl.h"
 
-/* Botch:  SLOW!  */
-
 void
 #if __STDC__
 mpz_gcdext (mpz_ptr g, mpz_ptr s, mpz_ptr t, mpz_srcptr a, mpz_srcptr b)
@@ -37,52 +37,101 @@ mpz_gcdext (g, s, t, a, b)
      mpz_srcptr b;
 #endif
 {
-  mpz_t s0, s1, q, r, x, d0, d1;
+  mp_size_t asize, bsize, usize, vsize;
+  mp_srcptr ap, bp;
+  mp_ptr up, vp;
+  mp_size_t gsize, ssize, tmp_ssize;
+  mp_ptr gp, sp, tmp_gp, tmp_sp;
+  mpz_srcptr u, v;
+  mpz_ptr ss, tt;
+  __mpz_struct stmp, gtmp;
+  TMP_DECL (marker);
+
+  TMP_MARK (marker);
+
+  /* mpn_gcdext requires that U >= V.  Therefore, we often have to swap U and
+     V.  This in turn leads to a lot of complications.  The computed cofactor
+     will be the wrong one, so we have to fix that up at the end.  */
+
+  asize = ABS (SIZ (a));
+  bsize = ABS (SIZ (b));
+  ap = PTR (a);
+  bp = PTR (b);
+  if (asize > bsize || (asize == bsize && mpn_cmp (ap, bp, asize) > 0))
+    {
+      usize = asize;
+      vsize = bsize;
+      up = (mp_ptr) TMP_ALLOC ((usize + 1) * BYTES_PER_MP_LIMB);
+      vp = (mp_ptr) TMP_ALLOC ((vsize + 1) * BYTES_PER_MP_LIMB);
+      MPN_COPY (up, ap, usize);
+      MPN_COPY (vp, bp, vsize);
+      u = a;
+      v = b;
+      ss = s;
+      tt = t;
+    }
+  else
+    {
+      usize = bsize;
+      vsize = asize;
+      up = (mp_ptr) TMP_ALLOC ((usize + 1) * BYTES_PER_MP_LIMB);
+      vp = (mp_ptr) TMP_ALLOC ((vsize + 1) * BYTES_PER_MP_LIMB);
+      MPN_COPY (up, bp, usize);
+      MPN_COPY (vp, ap, vsize);
+      u = b;
+      v = a;
+      ss = t;
+      tt = s;
+    }
 
-  mpz_init_set_ui (s0, 1L);
-  mpz_init_set_ui (s1, 0L);
-  mpz_init (q);
-  mpz_init (r);
-  mpz_init (x);
-  mpz_init_set (d0, a);
-  mpz_init_set (d1, b);
+  tmp_gp = (mp_ptr) TMP_ALLOC ((usize + 1) * BYTES_PER_MP_LIMB);
+  tmp_sp = (mp_ptr) TMP_ALLOC ((usize + 1) * BYTES_PER_MP_LIMB);
 
-  while (d1->_mp_size != 0)
+  if (vsize == 0)
     {
-      mpz_tdiv_qr (q, r, d0, d1);
-      mpz_set (d0, d1);
-      mpz_set (d1, r);
-
-      mpz_mul (x, s1, q);
-      mpz_sub (x, s0, x);
-      mpz_set (s0, s1);
-      mpz_set (s1, x);
+      tmp_sp[0] = 1;
+      tmp_ssize = 1;
+      MPN_COPY (tmp_gp, up, usize);
+      gsize = usize;
     }
+  else
+    gsize = mpn_gcdext (tmp_gp, tmp_sp, &tmp_ssize, up, usize, vp, vsize);
+  ssize = ABS (tmp_ssize);
+
+  PTR (&gtmp) = tmp_gp;
+  SIZ (&gtmp) = gsize;
 
-  if (t != NULL)
+  PTR (&stmp) = tmp_sp;
+  SIZ (&stmp) = (tmp_ssize ^ SIZ (u)) >= 0 ? ssize : -ssize;
+
+  if (tt != NULL)
     {
-      mpz_mul (x, s0, a);
-      mpz_sub (x, d0, x);
-      if (b->_mp_size == 0)
-       t->_mp_size = 0;
+      if (SIZ (v) == 0)
+       SIZ (tt) = 0;
       else
-       mpz_tdiv_q (t, x, b);
+       {
+         mpz_t x;
+         MPZ_TMP_INIT (x, ssize + usize + 1);
+         mpz_mul (x, &stmp, u);
+         mpz_sub (x, &gtmp, x);
+         mpz_tdiv_q (tt, x, v);
+       }
     }
-  mpz_set (s, s0);
-  mpz_set (g, d0);
-  if (g->_mp_size < 0)
+
+  if (ss != NULL)
     {
-      g->_mp_size = -g->_mp_size;
-      s->_mp_size = -s->_mp_size;
-      if (t != NULL)
-       t->_mp_size = -t->_mp_size;
+      if (ALLOC (ss) < ssize)
+       _mpz_realloc (ss, ssize);
+      sp = PTR (ss);
+      MPN_COPY (sp, tmp_sp, ssize);
+      SIZ (ss) = SIZ (&stmp);
     }
 
-  mpz_clear (s0);
-  mpz_clear (s1);
-  mpz_clear (q);
-  mpz_clear (r);
-  mpz_clear (x);
-  mpz_clear (d0);
-  mpz_clear (d1);
+  if (ALLOC (g) < gsize)
+    _mpz_realloc (g, gsize);
+  gp = PTR (g);
+  MPN_COPY (gp, tmp_gp, gsize);
+  SIZ (g) = gsize;
+
+  TMP_FREE (marker);
 }