mirror of
https://github.com/Atmosphere-NX/Atmosphere.git
synced 2024-12-23 10:52:13 +00:00
57 lines
No EOL
1.9 KiB
C++
57 lines
No EOL
1.9 KiB
C++
/*
|
|
* Copyright (c) 2018-2020 Atmosphère-NX
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify it
|
|
* under the terms and conditions of the GNU General Public License,
|
|
* version 2, as published by the Free Software Foundation.
|
|
*
|
|
* This program is distributed in the hope 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 a copy of the GNU General Public License
|
|
* along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
#include <vapours.hpp>
|
|
|
|
namespace ams::crypto {
|
|
|
|
bool IsSameBytes(const void *lhs, const void *rhs, size_t size) {
|
|
bool result;
|
|
u8 xor_acc, ltmp, rtmp;
|
|
size_t index;
|
|
|
|
__asm__ __volatile__(
|
|
/* Clear registers and prepare for comparison. */
|
|
" mov %w[xor_acc], #0\n"
|
|
" mov %w[index], #0\n"
|
|
" b 1f\n"
|
|
|
|
/* Compare one byte in constant time. */
|
|
"0:\n"
|
|
" ldrb %w[ltmp], [%[lhs]]\n"
|
|
" ldrb %w[rtmp], [%[rhs]]\n"
|
|
" adds %[lhs], %[lhs], #1\n"
|
|
" adds %[rhs], %[rhs], #1\n"
|
|
" eor %w[ltmp], %w[ltmp], %w[rtmp]\n"
|
|
" orr %w[xor_acc], %w[xor_acc], %w[ltmp]\n"
|
|
" adds %[index], %[index], #1\n"
|
|
|
|
/* Check if there is still data to compare. */
|
|
"1:\n"
|
|
" cmp %[index], %[size]\n"
|
|
" bcc 0b\n"
|
|
|
|
/* We're done, set result. */
|
|
" cmp %w[xor_acc], #0\n"
|
|
" cset %w[result], eq\n"
|
|
: [result]"=r"(result), [lhs]"+r"(lhs), [rhs]"+r"(rhs), [xor_acc]"=&r"(xor_acc), [index]"=&r"(index), [ltmp]"=&r"(ltmp), [rtmp]"=&r"(rtmp)
|
|
: [size]"r"(size)
|
|
: "cc"
|
|
);
|
|
|
|
return result;
|
|
}
|
|
|
|
} |