1*0957b409SSimon J. Gerraty /*
2*0957b409SSimon J. Gerraty * Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>
3*0957b409SSimon J. Gerraty *
4*0957b409SSimon J. Gerraty * Permission is hereby granted, free of charge, to any person obtaining
5*0957b409SSimon J. Gerraty * a copy of this software and associated documentation files (the
6*0957b409SSimon J. Gerraty * "Software"), to deal in the Software without restriction, including
7*0957b409SSimon J. Gerraty * without limitation the rights to use, copy, modify, merge, publish,
8*0957b409SSimon J. Gerraty * distribute, sublicense, and/or sell copies of the Software, and to
9*0957b409SSimon J. Gerraty * permit persons to whom the Software is furnished to do so, subject to
10*0957b409SSimon J. Gerraty * the following conditions:
11*0957b409SSimon J. Gerraty *
12*0957b409SSimon J. Gerraty * The above copyright notice and this permission notice shall be
13*0957b409SSimon J. Gerraty * included in all copies or substantial portions of the Software.
14*0957b409SSimon J. Gerraty *
15*0957b409SSimon J. Gerraty * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
16*0957b409SSimon J. Gerraty * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
17*0957b409SSimon J. Gerraty * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
18*0957b409SSimon J. Gerraty * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
19*0957b409SSimon J. Gerraty * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
20*0957b409SSimon J. Gerraty * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
21*0957b409SSimon J. Gerraty * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
22*0957b409SSimon J. Gerraty * SOFTWARE.
23*0957b409SSimon J. Gerraty */
24*0957b409SSimon J. Gerraty
25*0957b409SSimon J. Gerraty #include "inner.h"
26*0957b409SSimon J. Gerraty
27*0957b409SSimon J. Gerraty /* see inner.h */
28*0957b409SSimon J. Gerraty uint32_t
br_i31_bit_length(uint32_t * x,size_t xlen)29*0957b409SSimon J. Gerraty br_i31_bit_length(uint32_t *x, size_t xlen)
30*0957b409SSimon J. Gerraty {
31*0957b409SSimon J. Gerraty uint32_t tw, twk;
32*0957b409SSimon J. Gerraty
33*0957b409SSimon J. Gerraty tw = 0;
34*0957b409SSimon J. Gerraty twk = 0;
35*0957b409SSimon J. Gerraty while (xlen -- > 0) {
36*0957b409SSimon J. Gerraty uint32_t w, c;
37*0957b409SSimon J. Gerraty
38*0957b409SSimon J. Gerraty c = EQ(tw, 0);
39*0957b409SSimon J. Gerraty w = x[xlen];
40*0957b409SSimon J. Gerraty tw = MUX(c, w, tw);
41*0957b409SSimon J. Gerraty twk = MUX(c, (uint32_t)xlen, twk);
42*0957b409SSimon J. Gerraty }
43*0957b409SSimon J. Gerraty return (twk << 5) + BIT_LENGTH(tw);
44*0957b409SSimon J. Gerraty }
45