fixed issues when running on hardware

kernel/memory/mm.c

@@ -1,4 +1,5 @@
 #include "memory/mm.h"
+#include "lib/print.h"
 #include "multiboot.h"
 
 #include <stddef.h>
@@ -61,6 +62,7 @@ static void parse_multiboot_mmap(void* base, uint32_t limit) {
             uint32_t usable_start, usable_end, usable_size;
             usable_size = align(region_start, entry->len, &usable_start, &usable_end);
             if (usable_size <=  4096) {
+                entry = (multiboot_mmap_entry*)((uint32_t)entry + entry_size);
                 continue;
             }
 
@@ -139,6 +141,8 @@ void init_pmm(void* mmap_base, uint32_t mmap_limit) {
     if (mmap_base != NULL && mmap_limit > 0) {
         parse_multiboot_mmap(mmap_base, mmap_limit);
     }
+
+    kprintf("total free memory: %dMB\n", total_available_memory / 1024 / 1024);
 }
 
 void init_page_tables() {