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+/*
+ * mplogic.c
+ *
+ * Bitwise logical operations on MPI values
+ *
+ * ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0/LGPL 2.1
+ *
+ * The contents of this file are subject to the Mozilla Public License Version
+ * 1.1 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+ * for the specific language governing rights and limitations under the
+ * License.
+ *
+ * The Original Code is the MPI Arbitrary Precision Integer Arithmetic library.
+ *
+ * The Initial Developer of the Original Code is
+ * Michael J. Fromberger.
+ * Portions created by the Initial Developer are Copyright (C) 1998
+ * the Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s):
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either the GNU General Public License Version 2 or later (the "GPL"), or
+ * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+ * in which case the provisions of the GPL or the LGPL are applicable instead
+ * of those above. If you wish to allow use of your version of this file only
+ * under the terms of either the GPL or the LGPL, and not to allow others to
+ * use your version of this file under the terms of the MPL, indicate your
+ * decision by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL or the LGPL. If you do not delete
+ * the provisions above, a recipient may use your version of this file under
+ * the terms of any one of the MPL, the GPL or the LGPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+/*
+ * Copyright 2007 Sun Microsystems, Inc. All rights reserved.
+ * Use is subject to license terms.
+ *
+ * Sun elects to use this software under the MPL license.
+ */
+
+#pragma ident "%Z%%M% %I% %E% SMI"
+
+/* $Id: mplogic.c,v 1.15 2004/04/27 23:04:36 gerv%gerv.net Exp $ */
+
+#include "mpi-priv.h"
+#include "mplogic.h"
+
+/* {{{ Lookup table for population count */
+
+static unsigned char bitc[] = {
+ 0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4,
+ 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
+ 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
+ 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
+ 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
+ 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
+ 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
+ 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
+ 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
+ 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
+ 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
+ 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
+ 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
+ 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
+ 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
+ 4, 5, 5, 6, 5, 6, 6, 7, 5, 6, 6, 7, 6, 7, 7, 8
+};
+
+/* }}} */
+
+/*
+ mpl_rsh(a, b, d) - b = a >> d
+ mpl_lsh(a, b, d) - b = a << d
+ */
+
+/* {{{ mpl_rsh(a, b, d) */
+
+mp_err mpl_rsh(const mp_int *a, mp_int *b, mp_digit d)
+{
+ mp_err res;
+
+ ARGCHK(a != NULL && b != NULL, MP_BADARG);
+
+ if((res = mp_copy(a, b)) != MP_OKAY)
+ return res;
+
+ s_mp_div_2d(b, d);
+
+ return MP_OKAY;
+
+} /* end mpl_rsh() */
+
+/* }}} */
+
+/* {{{ mpl_lsh(a, b, d) */
+
+mp_err mpl_lsh(const mp_int *a, mp_int *b, mp_digit d)
+{
+ mp_err res;
+
+ ARGCHK(a != NULL && b != NULL, MP_BADARG);
+
+ if((res = mp_copy(a, b)) != MP_OKAY)
+ return res;
+
+ return s_mp_mul_2d(b, d);
+
+} /* end mpl_lsh() */
+
+/* }}} */
+
+/*------------------------------------------------------------------------*/
+/*
+ mpl_set_bit
+
+ Returns MP_OKAY or some error code.
+ Grows a if needed to set a bit to 1.
+ */
+mp_err mpl_set_bit(mp_int *a, mp_size bitNum, mp_size value)
+{
+ mp_size ix;
+ mp_err rv;
+ mp_digit mask;
+
+ ARGCHK(a != NULL, MP_BADARG);
+
+ ix = bitNum / MP_DIGIT_BIT;
+ if (ix + 1 > MP_USED(a)) {
+ rv = s_mp_pad(a, ix + 1);
+ if (rv != MP_OKAY)
+ return rv;
+ }
+
+ bitNum = bitNum % MP_DIGIT_BIT;
+ mask = (mp_digit)1 << bitNum;
+ if (value)
+ MP_DIGIT(a,ix) |= mask;
+ else
+ MP_DIGIT(a,ix) &= ~mask;
+ s_mp_clamp(a);
+ return MP_OKAY;
+}
+
+/*
+ mpl_get_bit
+
+ returns 0 or 1 or some (negative) error code.
+ */
+mp_err mpl_get_bit(const mp_int *a, mp_size bitNum)
+{
+ mp_size bit, ix;
+ mp_err rv;
+
+ ARGCHK(a != NULL, MP_BADARG);
+
+ ix = bitNum / MP_DIGIT_BIT;
+ ARGCHK(ix <= MP_USED(a) - 1, MP_RANGE);
+
+ bit = bitNum % MP_DIGIT_BIT;
+ rv = (mp_err)(MP_DIGIT(a, ix) >> bit) & 1;
+ return rv;
+}
+
+/*
+ mpl_get_bits
+ - Extracts numBits bits from a, where the least significant extracted bit
+ is bit lsbNum. Returns a negative value if error occurs.
+ - Because sign bit is used to indicate error, maximum number of bits to
+ be returned is the lesser of (a) the number of bits in an mp_digit, or
+ (b) one less than the number of bits in an mp_err.
+ - lsbNum + numbits can be greater than the number of significant bits in
+ integer a, as long as bit lsbNum is in the high order digit of a.
+ */
+mp_err mpl_get_bits(const mp_int *a, mp_size lsbNum, mp_size numBits)
+{
+ mp_size rshift = (lsbNum % MP_DIGIT_BIT);
+ mp_size lsWndx = (lsbNum / MP_DIGIT_BIT);
+ mp_digit * digit = MP_DIGITS(a) + lsWndx;
+ mp_digit mask = ((1 << numBits) - 1);
+
+ ARGCHK(numBits < CHAR_BIT * sizeof mask, MP_BADARG);
+ ARGCHK(MP_HOWMANY(lsbNum, MP_DIGIT_BIT) <= MP_USED(a), MP_RANGE);
+
+ if ((numBits + lsbNum % MP_DIGIT_BIT <= MP_DIGIT_BIT) ||
+ (lsWndx + 1 >= MP_USED(a))) {
+ mask &= (digit[0] >> rshift);
+ } else {
+ mask &= ((digit[0] >> rshift) | (digit[1] << (MP_DIGIT_BIT - rshift)));
+ }
+ return (mp_err)mask;
+}
+
+/*
+ mpl_significant_bits
+ returns number of significnant bits in abs(a).
+ returns 1 if value is zero.
+ */
+mp_err mpl_significant_bits(const mp_int *a)
+{
+ mp_err bits = 0;
+ int ix;
+
+ ARGCHK(a != NULL, MP_BADARG);
+
+ ix = MP_USED(a);
+ for (ix = MP_USED(a); ix > 0; ) {
+ mp_digit d;
+ d = MP_DIGIT(a, --ix);
+ if (d) {
+ while (d) {
+ ++bits;
+ d >>= 1;
+ }
+ break;
+ }
+ }
+ bits += ix * MP_DIGIT_BIT;
+ if (!bits)
+ bits = 1;
+ return bits;
+}
+
+/*------------------------------------------------------------------------*/
+/* HERE THERE BE DRAGONS */
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