1 files changed, 80 insertions, 0 deletions
diff --git a/ghc/runtime/gmp/mpz_gcdext.c b/ghc/runtime/gmp/mpz_gcdext.c
new file mode 100644
index 0000000000..183b9bd197
--- /dev/null
+++ b/ghc/runtime/gmp/mpz_gcdext.c
@@ -0,0 +1,80 @@
+/* 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 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"
+
+/* Botch:  SLOW!  */
+
+void
+#ifdef __STDC__
+mpz_gcdext (MP_INT *g, MP_INT *s, MP_INT *t, const MP_INT *a, const MP_INT *b)
+#else
+mpz_gcdext (g, s, t, a, b)
+     MP_INT *g;
+     MP_INT *s;
+     MP_INT *t;
+     const MP_INT *a;
+     const MP_INT *b;
+#endif
+{
+  MP_INT s0, s1, q, r, x, d0, d1;
+
+  mpz_init_set_ui (&s0, 1);
+  mpz_init_set_ui (&s1, 0);
+  mpz_init (&q);
+  mpz_init (&r);
+  mpz_init (&x);
+  mpz_init_set (&d0, a);
+  mpz_init_set (&d1, b);
+
+  while (d1.size != 0)
+    {
+      mpz_divmod (&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);
+    }
+
+  if (t != NULL)
+    {
+      mpz_mul (&x, &s0, a);
+      mpz_sub (&x, &d0, &x);
+      if (b->size == 0)
+	t->size = 0;
+      else
+	mpz_div (t, &x, b);
+    }
+  mpz_set (s, &s0);
+  mpz_set (g, &d0);
+
+  mpz_clear (&s0);
+  mpz_clear (&s1);
+  mpz_clear (&q);
+  mpz_clear (&r);
+  mpz_clear (&x);
+  mpz_clear (&d0);
+  mpz_clear (&d1);
+}