obs-studio/libobs/util/util_uint128.h

101 lines
2.3 KiB
C

/*
* Copyright (c) 2015 Hugh Bailey <obs.jim@gmail.com>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#pragma once
struct util_uint128 {
union {
uint32_t i32[4];
struct {
uint64_t low;
uint64_t high;
};
};
};
typedef struct util_uint128 util_uint128_t;
static inline util_uint128_t util_add128(util_uint128_t a, util_uint128_t b)
{
util_uint128_t out;
uint64_t val;
val = (a.low & 0xFFFFFFFFULL) + (b.low & 0xFFFFFFFFULL);
out.i32[0] = (uint32_t)(val & 0xFFFFFFFFULL);
val >>= 32;
val += (a.low >> 32) + (b.low >> 32);
out.i32[1] = (uint32_t)val;
val >>= 32;
val += (a.high & 0xFFFFFFFFULL) + (b.high & 0xFFFFFFFFULL);
out.i32[2] = (uint32_t)(val & 0xFFFFFFFFULL);
val >>= 32;
val += (a.high >> 32) + (b.high >> 32);
out.i32[3] = (uint32_t)val;
return out;
}
static inline util_uint128_t util_lshift64(uint64_t a, int num)
{
util_uint128_t val;
val.low = a << num;
val.high = a >> (64 - num);
return val;
}
static inline util_uint128_t util_mul64_64(uint64_t a, uint64_t b)
{
util_uint128_t out;
uint64_t m;
m = (a & 0xFFFFFFFFULL) * (b & 0xFFFFFFFFULL);
out.low = m;
out.high = 0;
m = (a >> 32) * (b & 0xFFFFFFFFULL);
out = util_add128(out, util_lshift64(m, 32));
m = (a & 0xFFFFFFFFULL) * (b >> 32);
out = util_add128(out, util_lshift64(m, 32));
m = (a >> 32) * (b >> 32);
out = util_add128(out, util_lshift64(m, 64));
return out;
}
static inline util_uint128_t util_div128_32(util_uint128_t a, uint32_t b)
{
util_uint128_t out;
uint64_t val = 0;
for (int i = 3; i >= 0; i--) {
val = (val << 32) | a.i32[i];
if (val < b) {
out.i32[i] = 0;
continue;
}
out.i32[i] = (uint32_t)(val / b);
val = val % b;
}
return out;
}