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-rw-r--r--gnu/lib/libgmp/mpz_mul_2exp.c68
1 files changed, 68 insertions, 0 deletions
diff --git a/gnu/lib/libgmp/mpz_mul_2exp.c b/gnu/lib/libgmp/mpz_mul_2exp.c
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+++ b/gnu/lib/libgmp/mpz_mul_2exp.c
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+/* mpz_mul_2exp -- Multiply a bignum by 2**CNT
+
+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__
+mpz_mul_2exp (MP_INT *w, const MP_INT *u, unsigned long int cnt)
+#else
+mpz_mul_2exp (w, u, cnt)
+ MP_INT *w;
+ const MP_INT *u;
+ unsigned long int cnt;
+#endif
+{
+ mp_size usize = u->size;
+ mp_size abs_usize = ABS (usize);
+ mp_size wsize;
+ mp_size limb_cnt;
+ mp_ptr wp;
+ mp_limb wdigit;
+
+ if (usize == 0)
+ {
+ w->size = 0;
+ return;
+ }
+
+ limb_cnt = cnt / BITS_PER_MP_LIMB;
+ wsize = abs_usize + limb_cnt + 1;
+ if (w->alloc < wsize)
+ _mpz_realloc (w, wsize);
+ wp = w->d;
+
+ wdigit = mpn_lshift (wp + limb_cnt, u->d, abs_usize,
+ cnt % BITS_PER_MP_LIMB);
+ wsize = abs_usize + limb_cnt;
+
+ if (wdigit != 0)
+ {
+ wp[wsize] = wdigit;
+ wsize++;
+ }
+
+ /* Zero all whole digits at low end. Do it here and not before calling
+ mpn_lshift, not to loose for U == W. */
+ MPN_ZERO (wp, limb_cnt);
+
+ w->size = (usize >= 0) ? wsize : -wsize;
+}
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