Nigel
dea8ab7d71
Added new entries to .gitignore Moved away from source directory as central spot for all source code
143 lines
3.9 KiB
C++
143 lines
3.9 KiB
C++
#include "./memory.h"
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uint32_t* memoryBitMap;
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/*
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*/
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void PhysicalMemory::setup( MemoryInfo* memory) {
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// calculate the maximum number of blocks
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max_blocks = KB_TO_BLOCKS(memory->TotalMemory);
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used_blocks = 0;
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memoryBitMap = (uint32_t*) 0x00a00000;
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printf("Maximum Number of blocks: 0x%x, Number of bytes for memMap: 0x%x\n", max_blocks , (max_blocks/8));
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//Size of memory map
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uint32_t memMap_size = (max_blocks / 8 ) ;
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printf("Memory Map size: 0x%x\n", memMap_size );
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printf("size of int in bytes: 0x%x \n" , sizeof(int));
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// Set all places in memory as free
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memset(memoryBitMap, 0xFF, memMap_size );
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}
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// NOTE: this can only give blocks of 4kb at a time!
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void* PhysicalMemory::allocate_block() {
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uint8_t blocks_available = max_blocks - used_blocks;
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// Are there any blocks available?
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if( blocks_available <= 0)
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{
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printf("No blocks available. Blocks Delta: 0x%x\n", blocks_available);
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return 0;
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}
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// Find 1 free block somewhere
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int free_block_index = bitmap_first_unset(memoryBitMap, (max_blocks /8) /*memMap Size*/ );
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if(free_block_index == -1)
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{
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printf("Could not find a good block!\n");
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// Could not find a block
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return (void*)0xFFFF;
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}
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if(free_block_index == 0)
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printf("Somethings wrong!!!\n");
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// Set the block to be used!
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bitmap_unset(memoryBitMap, free_block_index);
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// Increase the used_block count!
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used_blocks++;
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printf("used blocks: 0x%x\n", used_blocks);
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// return the pointer to the physical address
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return (void*) (BLOCK_SIZE * free_block_index);
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}
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void PhysicalMemory::free_block(void* p) {
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// If it is a null pointer we don't need to do anything.
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if(p==0) {
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return;
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}
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// calculate the index into the bitmap
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int index = ((uint32_t) p) / BLOCK_SIZE;
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// set the block to be free
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bitmap_set(memoryBitMap, index);
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used_blocks--;
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printf("used blocks: 0x%x, after free\n", used_blocks);
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}
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void PhysicalMemory::allocate_region(uint32_t startAddress, uint32_t size) {
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// every bit should be 4KiB
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// every byte is 8*4KiB = 32KiB
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int NumberOfBlocksToAllocate = ( size / 1024) / 4 / 8 + 1;
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int startBlock = (startAddress / 1024) / 4 / 8 ;
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// printf("NumberOfBlocksToAllocate: 0x%x\n", NumberOfBlocksToAllocate);
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//printf( "start block: 0x%x\n" , startBlock);
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for( int i = 0; i < NumberOfBlocksToAllocate; i++)
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{
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//printf("ALLOCATE BLOCK: 0x%x\n" , startBlock + i );
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bitmap_unset(memoryBitMap, startBlock+ i);
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used_blocks++;
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}
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}
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void PhysicalMemory::deallocate_region(uint32_t StartAddress , uint32_t size ) {
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// NOT IMPLEMENTED YET
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}
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void mapMultibootMemoryMap( MemoryInfo* memInfo , multiboot_info_t *mbt) {
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printf("mmap_addr = 0x%x, mmap_length = 0x%x\n",
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(unsigned) mbt->mmap_addr, (unsigned) mbt->mmap_length);
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multiboot_memory_map_t *mmap = (multiboot_memory_map_t*) mbt->mmap_addr;
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for (; (unsigned long) mmap < mbt->mmap_addr + mbt->mmap_length; mmap = (multiboot_memory_map_t *) ((unsigned long) mmap + mmap->size + sizeof(mmap->size))){
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if ( mmap->type == MULTIBOOT_MEMORY_AVAILABLE){
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memInfo->TotalMemory += mmap->len;
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} else {
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memInfo->ReservedMemory += mmap->len;
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}
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print_Multiboot_memory_Map(mmap);
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}
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}
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/**
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* @brief Debug Verbose functions
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*
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* @param mmap
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*/
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void print_Multiboot_memory_Map(multiboot_memory_map_t* mmap) {
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printf(
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"size = 0x%x, base_addr = 0x%x%08x, length = 0x%x%08x, type = 0x%x\n",
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(unsigned) mmap->size,
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(unsigned) (mmap->addr >> 32),
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(unsigned) (mmap->addr & 0xffffffff),
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(unsigned) (mmap->len >> 32),
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(unsigned) (mmap->len & 0xffffffff),
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(unsigned) mmap->type
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);
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}
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