mirror of
https://github.com/justinian/jsix.git
synced 2025-12-09 16:04:32 -08:00
346c172b32
This new libc is mostly from scratch, with *printf() functions provided by Marco Paland and Eyal Rozenberg's tiny printf library, and malloc and friends provided by dlmalloc.
42 lines
1.0 KiB
C++
42 lines
1.0 KiB
C++
#pragma once
|
|
/** \file j6libc/bits.h
|
|
* Internal helpers for bitwise math.
|
|
*
|
|
* This file is part of the C standard library for the jsix operating
|
|
* system.
|
|
*
|
|
* This Source Code Form is subject to the terms of the Mozilla Public
|
|
* License, v. 2.0. If a copy of the MPL was not distributed with this
|
|
* file, You can obtain one at https://mozilla.org/MPL/2.0/.
|
|
*/
|
|
|
|
#ifndef __cplusplus
|
|
#error "__j6libc/bits.h included by non-C++ code"
|
|
#endif
|
|
|
|
#include <stdint.h>
|
|
#include <__j6libc/size_t.h>
|
|
|
|
namespace __j6libc {
|
|
|
|
constexpr size_t log2(size_t n) {
|
|
return n < 2 ? 1 : 1 + log2(n/2);
|
|
}
|
|
|
|
constexpr size_t word_bytes = sizeof(void*);
|
|
constexpr size_t word_bits = word_bytes << 3;
|
|
constexpr uintptr_t word_align_mask = word_bytes - 1;
|
|
constexpr unsigned word_shift = log2(word_bytes);
|
|
|
|
template <typename T>
|
|
inline bool is_aligned(uintptr_t addr) {
|
|
return (addr & (sizeof(T)-1)) == 0;
|
|
}
|
|
|
|
template <typename T, typename S>
|
|
inline bool is_aligned(S *p) {
|
|
return is_aligned<T>(reinterpret_cast<uintptr_t>(p));
|
|
}
|
|
|
|
} // namespace __j6libc
|