minor additions to the kernel heap and adding acpi

kernel/heap.c

@@ -1,6 +1,63 @@
 #include "heap.h"
+#include <stdint.h>
+
+typedef struct heap_block {
+    size_t size;
+    struct heap_block *next;
+    int is_free;
+} heap_block_t;
+
+static heap_block_t *free_list = NULL;
+static void *heap_start_ptr = NULL;
+static void *heap_end_ptr = NULL;
+
+void heap_init(void *heap_start, void *heap_end) {
+    heap_start_ptr = heap_start;
+    heap_end_ptr = heap_end;
+
+    free_list = (heap_block_t *)heap_start;
+    free_list->size = (uintptr_t)heap_end - (uintptr_t)heap_start - sizeof(heap_block_t);
+    free_list->next = NULL;
+    free_list->is_free = 1;
+}
 
 void *heap_alloc(size_t size) {
-    // Heap allocation code
-    return NULL;
+    heap_block_t *current = free_list;
+
+    while (current != NULL) {
+        if (current->is_free && current->size >= size) {
+            // If it's a large block, split it
+            if (current->size > size + sizeof(heap_block_t)) {
+                heap_block_t *new_block = (heap_block_t *)((uintptr_t)current + sizeof(heap_block_t) + size);
+                new_block->size = current->size - size - sizeof(heap_block_t);
+                new_block->next = current->next;
+                new_block->is_free = 1;
+
+                current->next = new_block;
+                current->size = size;
+            }
+
+            current->is_free = 0;
+            return (void *)((uintptr_t)current + sizeof(heap_block_t));
+        }
+
+        current = current->next;
+    }
+
+    return NULL; // Out of memory
+}
+
+void heap_free(void *ptr) {
+    if (ptr == NULL) return;
+
+    heap_block_t *block = (heap_block_t *)((uintptr_t)ptr - sizeof(heap_block_t));
+    block->is_free = 1;
+
+    // Coalesce with next block
+    if (block->next && block->next->is_free) {
+        block->size += block->next->size + sizeof(heap_block_t);
+        block->next = block->next->next;
+    }
+
+    // TODO: Coalesce with previous block for better compaction
 }