1=pod 2 3=head1 NAME 4 5BN_set_bit, BN_clear_bit, BN_is_bit_set, BN_mask_bits, BN_lshift, 6BN_lshift1, BN_rshift, BN_rshift1 - bit operations on BIGNUMs 7 8=head1 SYNOPSIS 9 10 #include <openssl/bn.h> 11 12 int BN_set_bit(BIGNUM *a, int n); 13 int BN_clear_bit(BIGNUM *a, int n); 14 15 int BN_is_bit_set(const BIGNUM *a, int n); 16 17 int BN_mask_bits(BIGNUM *a, int n); 18 19 int BN_lshift(BIGNUM *r, const BIGNUM *a, int n); 20 int BN_lshift1(BIGNUM *r, BIGNUM *a); 21 22 int BN_rshift(BIGNUM *r, BIGNUM *a, int n); 23 int BN_rshift1(BIGNUM *r, BIGNUM *a); 24 25=head1 DESCRIPTION 26 27BN_set_bit() sets bit B<n> in B<a> to 1 (C<a|=(1E<lt>E<lt>n)>). The 28number is expanded if necessary. 29 30BN_clear_bit() sets bit B<n> in B<a> to 0 (C<a&=~(1E<lt>E<lt>n)>). An 31error occurs if B<a> is shorter than B<n> bits. 32 33BN_is_bit_set() tests if bit B<n> in B<a> is set. 34 35BN_mask_bits() truncates B<a> to an B<n> bit number 36(C<a&=~((~0)E<lt>E<lt>n)>). An error occurs if B<a> already is 37shorter than B<n> bits. 38 39BN_lshift() shifts B<a> left by B<n> bits and places the result in 40B<r> (C<r=a*2^n>). Note that B<n> must be nonnegative. BN_lshift1() shifts 41B<a> left by one and places the result in B<r> (C<r=2*a>). 42 43BN_rshift() shifts B<a> right by B<n> bits and places the result in 44B<r> (C<r=a/2^n>). Note that B<n> must be nonnegative. BN_rshift1() shifts 45B<a> right by one and places the result in B<r> (C<r=a/2>). 46 47For the shift functions, B<r> and B<a> may be the same variable. 48 49=head1 RETURN VALUES 50 51BN_is_bit_set() returns 1 if the bit is set, 0 otherwise. 52 53All other functions return 1 for success, 0 on error. The error codes 54can be obtained by L<ERR_get_error(3)>. 55 56=head1 SEE ALSO 57 58L<BN_num_bytes(3)>, L<BN_add(3)> 59 60=head1 COPYRIGHT 61 62Copyright 2000-2020 The OpenSSL Project Authors. All Rights Reserved. 63 64Licensed under the OpenSSL license (the "License"). You may not use 65this file except in compliance with the License. You can obtain a copy 66in the file LICENSE in the source distribution or at 67L<https://www.openssl.org/source/license.html>. 68 69=cut 70