BarinkOS/kernel/memory/memory.cpp

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#include "./memory.h"
uint32_t* memoryBitMap;
/*
*/
void PhysicalMemory::setup( MemoryInfo* memory) {
// calculate the maximum number of blocks
max_blocks = KB_TO_BLOCKS(memory->TotalMemory);
used_blocks = 0;
memoryBitMap = (uint32_t*) 0x00a00000;
printf("Maximum Number of blocks: 0x%x, Number of bytes for memMap: 0x%x\n", max_blocks , (max_blocks/8));
//Size of memory map
uint32_t memMap_size = (max_blocks / 8 ) ;
printf("Memory Map size: 0x%x\n", memMap_size );
printf("size of int in bytes: 0x%x \n" , sizeof(int));
// Set all places in memory as free
memset(memoryBitMap, 0xFF, memMap_size );
}
// NOTE: this can only give blocks of 4kb at a time!
void* PhysicalMemory::allocate_block() {
uint8_t blocks_available = max_blocks - used_blocks;
// Are there any blocks available?
if( blocks_available <= 0)
{
printf("No blocks available. Blocks Delta: 0x%x\n", blocks_available);
return 0;
}
// Find 1 free block somewhere
int free_block_index = bitmap_first_unset(memoryBitMap, (max_blocks /8) /*memMap Size*/ );
if(free_block_index == -1)
{
printf("Could not find a good block!\n");
// Could not find a block
return (void*)0xFFFF;
}
if(free_block_index == 0)
printf("Somethings wrong!!!\n");
// Set the block to be used!
bitmap_unset(memoryBitMap, free_block_index);
// Increase the used_block count!
used_blocks++;
printf("used blocks: 0x%x\n", used_blocks);
// return the pointer to the physical address
return (void*) (BLOCK_SIZE * free_block_index);
}
void PhysicalMemory::free_block(void* p) {
// If it is a null pointer we don't need to do anything.
if(p==0) {
return;
}
// calculate the index into the bitmap
int index = ((uint32_t) p) / BLOCK_SIZE;
// set the block to be free
bitmap_set(memoryBitMap, index);
used_blocks--;
printf("used blocks: 0x%x, after free\n", used_blocks);
}
void PhysicalMemory::allocate_region(uint32_t startAddress, uint32_t size) {
// every bit should be 4KiB
// every byte is 8*4KiB = 32KiB
int NumberOfBlocksToAllocate = ( size / 1024) / 4 / 8 + 1;
int startBlock = (startAddress / 1024) / 4 / 8 ;
// printf("NumberOfBlocksToAllocate: 0x%x\n", NumberOfBlocksToAllocate);
//printf( "start block: 0x%x\n" , startBlock);
for( int i = 0; i < NumberOfBlocksToAllocate; i++)
{
//printf("ALLOCATE BLOCK: 0x%x\n" , startBlock + i );
bitmap_unset(memoryBitMap, startBlock+ i);
used_blocks++;
}
}
void PhysicalMemory::deallocate_region(uint32_t StartAddress , uint32_t size ) {
// NOT IMPLEMENTED YET
}
void mapMultibootMemoryMap( MemoryInfo* memInfo , multiboot_info_t *mbt) {
printf("mmap_addr = 0x%x, mmap_length = 0x%x\n",
(unsigned) mbt->mmap_addr, (unsigned) mbt->mmap_length);
multiboot_memory_map_t *mmap = (multiboot_memory_map_t*) mbt->mmap_addr;
for (; (unsigned long) mmap < mbt->mmap_addr + mbt->mmap_length; mmap = (multiboot_memory_map_t *) ((unsigned long) mmap + mmap->size + sizeof(mmap->size))){
if ( mmap->type == MULTIBOOT_MEMORY_AVAILABLE){
memInfo->TotalMemory += mmap->len;
} else {
memInfo->ReservedMemory += mmap->len;
}
print_Multiboot_memory_Map(mmap);
}
}
/**
* @brief Debug Verbose functions
*
* @param mmap
*/
void print_Multiboot_memory_Map(multiboot_memory_map_t* mmap) {
printf(
"size = 0x%x, base_addr = 0x%x%08x, length = 0x%x%08x, type = 0x%x\n",
(unsigned) mmap->size,
(unsigned) (mmap->addr >> 32),
(unsigned) (mmap->addr & 0xffffffff),
(unsigned) (mmap->len >> 32),
(unsigned) (mmap->len & 0xffffffff),
(unsigned) mmap->type
);
}