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authorDuncan Wilkie <antigravityd@gmail.com>2023-11-18 06:11:09 -0600
committerDuncan Wilkie <antigravityd@gmail.com>2023-11-18 06:11:09 -0600
commit11da511c784eca003deb90c23570f0873954e0de (patch)
treee14fdd3d5d6345956d67e79ae771d0633d28362b /gmp-6.3.0/mpn/generic/lshiftc.c
Initial commit.
Diffstat (limited to 'gmp-6.3.0/mpn/generic/lshiftc.c')
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diff --git a/gmp-6.3.0/mpn/generic/lshiftc.c b/gmp-6.3.0/mpn/generic/lshiftc.c
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+/* mpn_lshiftc -- Shift left low level with complement.
+
+Copyright 1991, 1993, 1994, 1996, 2000-2002, 2009 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 either:
+
+ * the GNU Lesser General Public License as published by the Free
+ Software Foundation; either version 3 of the License, or (at your
+ option) any later version.
+
+or
+
+ * the GNU General Public License as published by the Free Software
+ Foundation; either version 2 of the License, or (at your option) any
+ later version.
+
+or both in parallel, as here.
+
+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 copies of the GNU General Public License and the
+GNU Lesser General Public License along with the GNU MP Library. If not,
+see https://www.gnu.org/licenses/. */
+
+#include "gmp-impl.h"
+
+/* Shift U (pointed to by up and n limbs long) cnt bits to the left
+ and store the n least significant limbs of the result at rp.
+ Return the bits shifted out from the most significant limb.
+
+ Argument constraints:
+ 1. 0 < cnt < GMP_NUMB_BITS.
+ 2. If the result is to be written over the input, rp must be >= up.
+*/
+
+mp_limb_t
+mpn_lshiftc (mp_ptr rp, mp_srcptr up, mp_size_t n, unsigned int cnt)
+{
+ mp_limb_t high_limb, low_limb;
+ unsigned int tnc;
+ mp_size_t i;
+ mp_limb_t retval;
+
+ ASSERT (n >= 1);
+ ASSERT (cnt >= 1);
+ ASSERT (cnt < GMP_NUMB_BITS);
+ ASSERT (MPN_SAME_OR_DECR_P (rp, up, n));
+
+ up += n;
+ rp += n;
+
+ tnc = GMP_NUMB_BITS - cnt;
+ low_limb = *--up;
+ retval = low_limb >> tnc;
+ high_limb = (low_limb << cnt);
+
+ for (i = n - 1; i != 0; i--)
+ {
+ low_limb = *--up;
+ *--rp = (~(high_limb | (low_limb >> tnc))) & GMP_NUMB_MASK;
+ high_limb = low_limb << cnt;
+ }
+ *--rp = (~high_limb) & GMP_NUMB_MASK;
+
+ return retval;
+}