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trezor-firmware/crypto/monero/int-util.h
2019-04-15 19:14:52 +02:00

78 lines
3.1 KiB
C

// Copyright (c) 2014-2018, The Monero Project
//
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without modification, are
// permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this list of
// conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright notice, this list
// of conditions and the following disclaimer in the documentation and/or other
// materials provided with the distribution.
//
// 3. Neither the name of the copyright holder nor the names of its contributors may be
// used to endorse or promote products derived from this software without specific
// prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// Parts of this file are originally copyright (c) 2012-2013 The Cryptonote developers
#pragma once
#include <assert.h>
#include <stdint.h>
static inline uint64_t hi_dword(uint64_t val) {
return val >> 32;
}
static inline uint64_t lo_dword(uint64_t val) {
return val & 0xFFFFFFFF;
}
static inline uint64_t mul128(uint64_t multiplier, uint64_t multiplicand, uint64_t* product_hi) {
// multiplier = ab = a * 2^32 + b
// multiplicand = cd = c * 2^32 + d
// ab * cd = a * c * 2^64 + (a * d + b * c) * 2^32 + b * d
uint64_t a = hi_dword(multiplier);
uint64_t b = lo_dword(multiplier);
uint64_t c = hi_dword(multiplicand);
uint64_t d = lo_dword(multiplicand);
uint64_t ac = a * c;
uint64_t ad = a * d;
uint64_t bc = b * c;
uint64_t bd = b * d;
uint64_t adbc = ad + bc;
uint64_t adbc_carry = adbc < ad ? 1 : 0;
// multiplier * multiplicand = product_hi * 2^64 + product_lo
uint64_t product_lo = bd + (adbc << 32);
uint64_t product_lo_carry = product_lo < bd ? 1 : 0;
*product_hi = ac + (adbc >> 32) + (adbc_carry << 32) + product_lo_carry;
assert(ac <= *product_hi);
return product_lo;
}
#define SWAP64(x) ((((uint64_t) (x) & 0x00000000000000ff) << 56) | \
(((uint64_t) (x) & 0x000000000000ff00) << 40) | \
(((uint64_t) (x) & 0x0000000000ff0000) << 24) | \
(((uint64_t) (x) & 0x00000000ff000000) << 8) | \
(((uint64_t) (x) & 0x000000ff00000000) >> 8) | \
(((uint64_t) (x) & 0x0000ff0000000000) >> 24) | \
(((uint64_t) (x) & 0x00ff000000000000) >> 40) | \
(((uint64_t) (x) & 0xff00000000000000) >> 56))