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

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

diff --git a/ghc/runtime/gmp/mpz_mmod.c b/ghc/runtime/gmp/mpz_mmod.c
new file mode 100644 (file)
index 0000000..c1d3d3f
--- /dev/null
+++ b/ghc/runtime/gmp/mpz_mmod.c
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+/* mpz_mmod -- Mathematical MODulo, i.e. with the remainder
+   non-negative.
+
+Copyright (C) 1991, 1992 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_mmod (MP_INT *rem,
+            const MP_INT *dividend, const MP_INT *divisor)
+#else
+mpz_mmod (rem, dividend, divisor)
+     MP_INT *rem;
+     const MP_INT *dividend;
+     const MP_INT *divisor;
+#endif
+{
+  if ((dividend->size ^ divisor->size) >= 0)
+    {
+      /* When the dividend and the divisor has same sign, this function
+        gives same result as mpz_mod.  */
+      mpz_mod (rem, dividend, divisor);
+    }
+  else
+    {
+      MP_INT temp_divisor;     /* N.B.: lives until function returns! */
+ 
+      /* We need the original value of the divisor after the remainder has
+        been preliminary calculated.  We have to copy it to temporary
+        space if it's the same variable as REM.  */
+      if (rem == divisor)
+       {
+         MPZ_TMP_INIT (&temp_divisor, ABS (divisor->size));
+         mpz_set (&temp_divisor, divisor);
+         divisor = &temp_divisor;
+       }
+
+      mpz_mod (rem, dividend, divisor);
+      if (rem->size != 0)
+       mpz_add (rem, rem, divisor);
+    }
+}