fix userspace?

gdt.h

@@ -3,7 +3,42 @@
 
 #include <stdint.h>
 
-extern uint32_t stack_top;
+extern void* stack_top;
+
+//! set access bit
+#define I86_GDT_DESC_ACCESS 0x0001	//00000001
+
+//! descriptor is readable and writable. default: read only
+#define I86_GDT_DESC_READWRITE 0x0002  //00000010
+
+//! set expansion direction bit
+#define I86_GDT_DESC_EXPANSION 0x0004  //00000100
+
+//! executable code segment. Default: data segment
+#define I86_GDT_DESC_EXEC_CODE 0x0008  //00001000
+
+//! set code or data descriptor. defult: system defined descriptor
+#define I86_GDT_DESC_CODEDATA 0x0010  //00010000
+
+//! set dpl bits
+#define I86_GDT_DESC_DPL 0x0060	 //01100000
+
+//! set "in memory" bit
+#define I86_GDT_DESC_MEMORY 0x0080	//10000000
+
+/**	gdt descriptor grandularity bit flags	***/
+
+//! masks out limitHi (High 4 bits of limit)
+#define I86_GDT_GRAND_LIMITHI_MASK 0x0f	 //00001111
+
+//! set os defined bit
+#define I86_GDT_GRAND_OS 0x10  //00010000
+
+//! set if 32bit. default: 16 bit
+#define I86_GDT_GRAND_32BIT 0x40  //01000000
+
+//! 4k grandularity. default: none
+#define I86_GDT_GRAND_4K 0x80  //10000000
 
 typedef struct gdt_entry_t Gdt_entry;
 struct gdt_entry_t
@@ -58,6 +93,7 @@ struct tss_entry_t
     uint32_t ldt;
     uint16_t trap;
     uint16_t iomap;
+    uint16_t iopb_off;
 } __attribute__((packed));
 
 #endif