Improved build system

Added new entries to .gitignore Moved away from source directory as central spot for all source code
2023-02-20 00:29:06 +01:00
parent 2bcc79216e
commit dea8ab7d71
105 changed files with 140 additions and 156 deletions
--- a/kernel/memory/PhysicalMemoryManager.cpp
+++ b/kernel/memory/PhysicalMemoryManager.cpp
@ -0,0 +1,115 @@
+#include "./PhysicalMemoryManager.h"
+#define IS_ALIGNED(addr, align) !((addr) & ~((align) - 1))
+#define ALIGN(addr, align) (((addr) & ~((align) - 1 )) + (align))
+
+const uint32_t KERNEL_OFFSET = 0xC0000000;
+
+uint32_t* memoryBitMap;
+uint32_t pmmap_size;
+uint32_t max_blocks;
+int used_blocks;
+
+
+void SetupPhysicalMemoryManager(uint32_t mapAddress, uint32_t memorySize ) 
+{
+     /*
+        Every byte contains 8 pages
+        A page is 4096 kib 
+        Every block (1 bit) represent an page 
+    */
+
+    // Set the maximum number of blocks
+    max_blocks = (uint32_t)memorySize / BLOCK_SIZE ;
+    printf("Max Blocks: %d\n", max_blocks);
+    
+    // Set size of the bitmap 
+    uint32_t bitmap_size = max_blocks / 32;
+    printf("Bitmap size: %d bytes\n",bitmap_size);
+
+    // Set blocks used to zero
+    used_blocks = max_blocks;
+    
+    // set the address of the memory bitmap
+    memoryBitMap = (uint32_t*) mapAddress;
+
+    // Set all places in memory as free
+    memset(memoryBitMap, 0xFFFFFFFF,  max_blocks / 32  ); 
+}
+
+// NOTE: This can only give blocks of 4kb at a time!
+//         We might at some point want to allocate multiple blocks at once.
+void* 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 );
+
+    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 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 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 ;
+
+    for( int i = 0; i < NumberOfBlocksToAllocate; i++)
+    {
+        bitmap_unset(memoryBitMap, startBlock + i);// allocate region causes #PF Exception
+        used_blocks++;
+    }
+}
+
+void deallocate_region(uint32_t  StartAddress , uint32_t size ) {
+    // reverse of what happened in allocate_region
+    int NumberOfBlocks = (size / 1024) / 4 / 8 + 1;
+    int startBlock = (StartAddress / 1024) / 4 / 8;
+
+    for(int i = 0; i < NumberOfBlocks; i++)
+    {
+        bitmap_set(memoryBitMap, startBlock + i);
+        used_blocks --;
+    }
+}
+
+int GetUsedBlocks (){
+    return used_blocks;
+}