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add cal/splitbits.cal

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Landon Curt Noll
2023-07-21 23:02:51 -07:00
parent ccd579ecda
commit e05d904821
4 changed files with 177 additions and 15 deletions
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cal/splitbits.cal Normal file
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/*
* splitbits - split an integer into list on bit boundardies of a fixed size
*
* Copyright (C) 2018,2023 Landon Curt Noll
*
* Calc is open software; you can redistribute it and/or modify it under
* the terms of the version 2.1 of the GNU Lesser General Public License
* as published by the Free Software Foundation.
*
* Calc 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 Lesser General
* Public License for more details.
*
* A copy of version 2.1 of the GNU Lesser General Public License is
* distributed with calc under the filename COPYING-LGPL. You should have
* received a copy with calc; if not, write to Free Software Foundation, Inc.
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* Under source code control: 2006/06/07 14:10:11
* File existed as early as: 2006
*
* chongo <was here> /\oo/\ http://www.isthe.com/chongo/
* Share and enjoy! :-) http://www.isthe.com/chongo/tech/comp/calc/
*/
/*
* setup splitbits errors
*/
static E_SPLITBITS_1, E_SPLITBITS_2, E_SPLITBITS_3;
if (! iserror(E_SPLITBITS_1)) E_SPLITBITS_1 = newerror("1st argument to splitbits must be an integer");
if (! iserror(E_SPLITBITS_2)) E_SPLITBITS_2 = newerror("2nd argument to splitbits must be an integer");
if (! iserror(E_SPLITBITS_3)) E_SPLITBITS_3 = newerror("2nd argument must be an integer > 0");
/*
* define splitbits function
*/
define splitbits(x, b)
{
local ret; /* list to return */
local mask; /* 2^b-1 */
local x_is_reg = 0; /* true if x < 0 */
/* firewall */
if (! isint(x)) {
return error(E_SPLITBITS_1);
}
if (! isint(b)) {
return error(E_SPLITBITS_2);
}
if (b <= 0) {
return error(E_SPLITBITS_3);
}
/* special case: x == 0 */
if (x == 0) {
return list(0);
}
/* setup for splitting x */
ret = list();
mask = 2^b-1;
if (x < 0) {
x_is_reg = 1;
x = abs(x);
}
/* split x */
while (x > 0) {
printf("%d %x\n", size(ret), x);
if (x_is_reg) {
append(ret, xor(x & mask, mask));
} else {
append(ret, x & mask);
}
x >>= b;
}
/* return list */
return ret;
}