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/*
* bubbl
* Copyright (C) 2025 Raghuram Subramani <raghus2247@gmail.com>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef __mm_physical_mm_h
#define __mm_physical_mm_h
#include <common.h>
#include <stdbool.h>
#include <stdint.h>
/* TODO: Update this to 2MiB when PAE is enabled */
#define BLOCK_SIZE (4 * KiB)
#define BITMAP_ENTRY_SIZE 32
/* This is the maximum number of blocks for a 4GiB system. */
#define MAX_BLOCKS 1048576
namespace PhysicalMM
{
/* Initialize the memory map by getting all free regions, setting all blocks to
* used, initializing regions marked free by the memory map provided by
* multiboot, and deinitializing the memory used by the kernel */
void initialize(void);
/* Find and allocate a free memory block, returning the physical address of the
* block */
void *allocate_block(void);
/* Free an allocated memory block, given the physical address (from
* allocate_block) */
void free_block(void *physical_address);
/*-- BITMAP --*/
/* Marks the block as 'used' */
void set_used(const uint32_t bit,
uint32_t *total_free_blocks,
uint32_t *memory_map);
/* Marks the block as 'unused' */
void set_usable(const uint32_t bit,
uint32_t *total_free_blocks,
uint32_t *memory_map);
/* Returns:
* True if the bit is set (block is in use)
* False if the bit is unset (block isn't in use)
*/
bool test_bit(const uint32_t bit, uint32_t *memory_map);
}
#endif
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