Move kernel_address to 16 address line because of some bug

Author: scopeInfinity

include/fuzzy/memmgr/layout.h

@@ -9,10 +9,22 @@
 // and kernel's pid is 0.
 #define PID_KERNEL 0
 
+/*
+ * Bug:
+ *  Bootloader stage 2 is not able to load kernel if
+ *  memory address need 20 address lines (0x10000) in
+ *  our case.
+ *  It works as intended in QEMU but not in others.
+ * Mitigation:
+ *  - Forcing MEMORY_KERNEL_LOCATION to be represented
+ *    by 16 address lines. For ex 0xF000.
+ * Resolution:
+ *  - I'm not sure.
+ */
 #define MEMORY_APPBASE_LOCATION 0x10000
 
-#define memmgr_app_abs_location(pid) (MEMORY_APPBASE_LOCATION + (pid)*MEMORY_APP_SIZE)
+#define memmgr_app_abs_location(pid) ((pid==0)?0x0F000:(MEMORY_APPBASE_LOCATION + (pid)*MEMORY_APP_SIZE))
 #define memmgr_app_size(pid) (MEMORY_APP_SIZE)
 
-#define MEMORY_KERNEL_LOCATION memmgr_app_abs_location(PID_KERNEL)
-#define MEMORY_KERNEL_SIZE memmgr_app_size(PID_KERNEL)
+#define MEMORY_KERNEL_LOCATION (memmgr_app_abs_location(PID_KERNEL))
+#define MEMORY_KERNEL_SIZE (memmgr_app_size(PID_KERNEL))

src/bootloader/stage1.asm

@@ -17,6 +17,7 @@
         CLI
         MOV ax, 0x0000
         MOV es, ax                  ; es := 0
+        mov sp, 0x7FF0
 
         set_blinking 0
         clear_screen C_WHITE, C_BLACK

src/bootloader/stage2.c

@@ -83,10 +83,10 @@ void entry_stage() {
     set_color_fg(C_WHITE);
 
     print_log("");
+    enable_a20();
     load_static_library();
     load_kernel();
 
-    enable_a20();
     populate_gdt_table(&gdtr, gdt_table, GDT_TABLE_SIZE, 0);
 
     // Enter_protected_mode never returns.