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

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

diff --git a/ghc/runtime/gmp/mpq_mul.c b/ghc/runtime/gmp/mpq_mul.c
new file mode 100644 (file)
index 0000000..003d6ca
--- /dev/null
+++ b/ghc/runtime/gmp/mpq_mul.c
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+/* mpq_mul -- mutiply two rational numbers.
+
+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"
+
+void
+#ifdef __STDC__
+mpq_mul (MP_RAT *prod, const MP_RAT *m1, const MP_RAT *m2)
+#else
+mpq_mul (prod, m1, m2)
+     MP_RAT *prod;
+     const MP_RAT *m1;
+     const MP_RAT *m2;
+#endif
+{
+  MP_INT gcd1, gcd2;
+  MP_INT tmp1, tmp2;
+
+  mpz_init (&gcd1);
+  mpz_init (&gcd2);
+  mpz_init (&tmp1);
+  mpz_init (&tmp2);
+
+  /* PROD might be identical to either operand, so don't store the
+     result there until we are finished with the input operands.  We
+     dare to overwrite the numerator of PROD when we are finished
+     with the numerators of M1 and M1.  */
+
+  mpz_gcd (&gcd1, &(m1->num), &(m2->den));
+  mpz_gcd (&gcd2, &(m2->num), &(m1->den));
+
+  if (gcd1.size > 1 || gcd1.d[0] != 1)
+    mpz_div (&tmp1, &(m1->num), &gcd1);
+  else
+    mpz_set (&tmp1, &(m1->num));
+
+  if (gcd2.size > 1 || gcd2.d[0] != 1)
+    mpz_div (&tmp2, &(m2->num), &gcd2);
+  else
+    mpz_set (&tmp2, &(m2->num));
+
+  mpz_mul (&(prod->num), &tmp1, &tmp2);
+
+  if (gcd1.size > 1 || gcd1.d[0] != 1)
+    mpz_div (&tmp1, &(m2->den), &gcd1);
+  else
+    mpz_set (&tmp1, &(m2->den));
+
+  if (gcd2.size > 1 || gcd2.d[0] != 1)
+    mpz_div (&tmp2, &(m1->den), &gcd2);
+  else
+    mpz_set (&tmp2, &(m1->den));
+
+  mpz_mul (&(prod->den), &tmp1, &tmp2);
+
+  mpz_clear (&tmp2);
+  mpz_clear (&tmp1);
+  mpz_clear (&gcd2);
+  mpz_clear (&gcd1);
+}