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crypto: Implement BigNum/ExpMod

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Michael Scire 2020-02-23 06:51:32 -08:00
parent 981166783b
commit d675aa3414
14 changed files with 1086 additions and 33 deletions
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57
libraries/libvapours/source/crypto/crypto_memory_compare.arch.arm64.cpp Normal file
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/*
* 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;
}
}