[project @ 1996-01-08 20:28:12 by partain]

[ghc-hetmet.git] / ghc / runtime / gmp / mpq_set_si.c

diff --git a/ghc/runtime/gmp/mpq_set_si.c b/ghc/runtime/gmp/mpq_set_si.c
new file mode 100644 (file)
index 0000000..f108b6c
--- /dev/null
+++ b/ghc/runtime/gmp/mpq_set_si.c
@@ -0,0 +1,76 @@
+/* mpq_set_si(dest,ulong_num,ulong_den) -- Set DEST to the retional number
+   ULONG_NUM/ULONG_DEN.
+
+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"
+
+static unsigned long int
+gcd (x, y)
+     unsigned long int x, y;
+{
+  for (;;)
+    {
+      x = x % y;
+      if (x == 0)
+       return y;
+      y = y % x;
+      if (y == 0)
+       return x;
+    }
+}
+
+void
+#ifdef __STDC__
+mpq_set_si (MP_RAT *dest, signed long int num, unsigned long int den)
+#else
+mpq_set_si (dest, num, den)
+     MP_RAT *dest;
+     signed long int num;
+     unsigned long int den;
+#endif
+{
+  unsigned long int g;
+  unsigned long int abs_num;
+
+  abs_num = ABS (num);
+
+  if (num == 0)
+    {
+      /* Canonicalize 0/d to 0/1.  */
+      den = 1;
+      dest->num.size = 0;
+    }
+  else
+    {
+      /* Remove any common factor in NUM and DEN. */
+      /* Pass DEN as the second argument to gcd, in order to make the
+        gcd function divide by zero if DEN is zero.  */
+      g = gcd (abs_num, den);
+      abs_num /= g;
+      den /= g;
+
+      dest->num.d[0] = abs_num;
+      dest->num.size = num > 0 ? 1 : -1;
+    }
+
+  dest->den.d[0] = den;
+  dest->den.size = 1;
+}