1 /*
2 * Copyright (c) 2020 Hans Petter Selasky <hps@selasky.org>
3 *
4 * Permission to use, copy, modify, and distribute this software for any
5 * purpose with or without fee is hereby granted, provided that the above
6 * copyright notice and this permission notice appear in all copies.
7 *
8 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15 */
16
17 #pragma once
18
19 #if defined(_MSC_VER) && defined(_M_X64)
20 #include <intrin.h>
21 #endif
22
util_mul_div64(uint64_t num,uint64_t mul,uint64_t div)23 static inline uint64_t util_mul_div64(uint64_t num, uint64_t mul, uint64_t div)
24 {
25 #if defined(_MSC_VER) && defined(_M_X64)
26 unsigned __int64 high;
27 const unsigned __int64 low = _umul128(num, mul, &high);
28 unsigned __int64 rem;
29 return _udiv128(high, low, div, &rem);
30 #else
31 const uint64_t rem = num % div;
32 return (num / div) * mul + (rem * mul) / div;
33 #endif
34 }
35