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Diffstat (limited to 'ghc/runtime/gmp/mpz_mul.c')
-rw-r--r--ghc/runtime/gmp/mpz_mul.c114
1 files changed, 114 insertions, 0 deletions
diff --git a/ghc/runtime/gmp/mpz_mul.c b/ghc/runtime/gmp/mpz_mul.c
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+++ b/ghc/runtime/gmp/mpz_mul.c
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+/* mpz_mul -- Multiply two integers.
+
+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"
+
+#ifndef BERKELEY_MP
+void
+#ifdef __STDC__
+mpz_mul (MP_INT *w, const MP_INT *u, const MP_INT *v)
+#else
+mpz_mul (w, u, v)
+ MP_INT *w;
+ const MP_INT *u;
+ const MP_INT *v;
+#endif
+#else /* BERKELEY_MP */
+void
+#ifdef __STDC__
+mult (const MP_INT *u, const MP_INT *v, MP_INT *w)
+#else
+mult (u, v, w)
+ const MP_INT *u;
+ const MP_INT *v;
+ MP_INT *w;
+#endif
+#endif /* BERKELEY_MP */
+{
+ mp_size usize = u->size;
+ mp_size vsize = v->size;
+ mp_size wsize;
+ mp_size sign_product;
+ mp_ptr up, vp;
+ mp_ptr wp;
+ mp_ptr free_me = NULL;
+ size_t free_me_size;
+
+ sign_product = usize ^ vsize;
+ usize = ABS (usize);
+ vsize = ABS (vsize);
+
+ if (usize < vsize)
+ {
+ /* Swap U and V. */
+ {const MP_INT *t = u; u = v; v = t;}
+ {mp_size t = usize; usize = vsize; vsize = t;}
+ }
+
+ up = u->d;
+ vp = v->d;
+ wp = w->d;
+
+ /* Ensure W has space enough to store the result. */
+ wsize = usize + vsize;
+ if (w->alloc < wsize)
+ {
+ if (wp == up || wp == vp)
+ {
+ free_me = wp;
+ free_me_size = w->alloc;
+ }
+ else
+ (*_mp_free_func) (wp, w->alloc * BYTES_PER_MP_LIMB);
+
+ w->alloc = wsize;
+ wp = (mp_ptr) (*_mp_allocate_func) (wsize * BYTES_PER_MP_LIMB);
+ w->d = wp;
+ }
+ else
+ {
+ /* Make U and V not overlap with W. */
+ if (wp == up)
+ {
+ /* W and U are identical. Allocate temporary space for U. */
+ up = (mp_ptr) alloca (usize * BYTES_PER_MP_LIMB);
+ /* Is V identical too? Keep it identical with U. */
+ if (wp == vp)
+ vp = up;
+ /* Copy to the temporary space. */
+ MPN_COPY (up, wp, usize);
+ }
+ else if (wp == vp)
+ {
+ /* W and V are identical. Allocate temporary space for V. */
+ vp = (mp_ptr) alloca (vsize * BYTES_PER_MP_LIMB);
+ /* Copy to the temporary space. */
+ MPN_COPY (vp, wp, vsize);
+ }
+ }
+
+ wsize = mpn_mul (wp, up, usize, vp, vsize);
+ w->size = sign_product < 0 ? -wsize : wsize;
+ if (free_me != NULL)
+ (*_mp_free_func) (free_me, free_me_size * BYTES_PER_MP_LIMB);
+
+ alloca (0);
+}