mirror of
https://github.com/godotengine/godot.git
synced 2024-12-21 10:25:24 +08:00
696346f4cc
Co-authored-by: Gordon A Macpherson <gordon.a.macpherson@gmail.com> Co-authored-by: Rémi Verschelde <rverschelde@gmail.com>
49 lines
1.4 KiB
C++
49 lines
1.4 KiB
C++
// SPDX-License-Identifier: Apache-2.0
|
|
// ----------------------------------------------------------------------------
|
|
// Copyright 2011-2021 Arm Limited
|
|
//
|
|
// Licensed under the Apache License, Version 2.0 (the "License"); you may not
|
|
// use this file except in compliance with the License. You may obtain a copy
|
|
// of the License at:
|
|
//
|
|
// http://www.apache.org/licenses/LICENSE-2.0
|
|
//
|
|
// Unless required by applicable law or agreed to in writing, software
|
|
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
|
|
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
|
|
// License for the specific language governing permissions and limitations
|
|
// under the License.
|
|
// ----------------------------------------------------------------------------
|
|
|
|
#include "astcenc_mathlib.h"
|
|
|
|
/**
|
|
* @brief 64-bit rotate left.
|
|
*
|
|
* @param val The value to rotate.
|
|
* @param count The rotation, in bits.
|
|
*/
|
|
static inline uint64_t rotl(uint64_t val, int count)
|
|
{
|
|
return (val << count) | (val >> (64 - count));
|
|
}
|
|
|
|
/* See header for documentation. */
|
|
void astc::rand_init(uint64_t state[2])
|
|
{
|
|
state[0] = 0xfaf9e171cea1ec6bULL;
|
|
state[1] = 0xf1b318cc06af5d71ULL;
|
|
}
|
|
|
|
/* See header for documentation. */
|
|
uint64_t astc::rand(uint64_t state[2])
|
|
{
|
|
uint64_t s0 = state[0];
|
|
uint64_t s1 = state[1];
|
|
uint64_t res = s0 + s1;
|
|
s1 ^= s0;
|
|
state[0] = rotl(s0, 24) ^ s1 ^ (s1 << 16);
|
|
state[1] = rotl(s1, 37);
|
|
return res;
|
|
}
|