1 files changed, 51 insertions, 0 deletions
diff --git a/kernel/mm/physical_mm/allocation.c b/kernel/mm/physical_mm/allocation.c
new file mode 100644
index 0000000..85d945f
--- /dev/null
+++ b/kernel/mm/physical_mm/allocation.c
@@ -0,0 +1,51 @@
+#include <stdbool.h>
+#include <stdint.h>
+
+#include <libk/stdio.h>
+
+#include <mm/physical_mm.h>
+
+#include <kernel/halt.h>
+
+uint32_t
+physical_mm_find_first_free_block(uint32_t *memory_map)
+{
+  /* TODO: Why doesn't using block_count instead of MAX_BLOCKS work? */
+  for (uint32_t i = 0; i < MAX_BLOCKS / BITMAP_ENTRY_SIZE; i++)
+    /* At least one block in the entry isn't in use */
+    if (memory_map[i] != 0xffffffff)
+      /* Test each bit to see if it's zero */
+      for (uint32_t j = 0; j < BITMAP_ENTRY_SIZE; j++)
+        if (!physical_mm_test_bit(i * BITMAP_ENTRY_SIZE + j, memory_map))
+          return i * BITMAP_ENTRY_SIZE + j;
+
+  /* Shouldn't be reached, since we're keeping track of the number of free
+   * blocks */
+  ASSERT_NOT_REACHED();
+  return -1;
+}
+
+void *
+physical_mm_allocate_block(uint32_t *total_free_blocks, uint32_t *memory_map)
+{
+  if (total_free_blocks == 0) {
+    printk("physical_mm", "No more free blocks!");
+    return NULL;
+  }
+
+  uint32_t block = physical_mm_find_first_free_block(memory_map);
+
+  physical_mm_set_used(block, total_free_blocks, memory_map);
+
+  uint32_t physical_address = block * BLOCK_SIZE;
+  return (void *) physical_address;
+}
+
+void
+physical_mm_free_block(void *physical_address,
+                       uint32_t *total_free_blocks,
+                       uint32_t *memory_map)
+{
+  uint32_t block = ((uint32_t) physical_address) / BLOCK_SIZE;
+  physical_mm_set_usable(block, total_free_blocks, memory_map);
+}