#define DESC_TYPE_SHIFT 8
#define DESC_A_MASK (1 << 8)
-#define DESC_CS_MASK (1 << 11)
-#define DESC_C_MASK (1 << 10)
-#define DESC_R_MASK (1 << 9)
+#define DESC_CS_MASK (1 << 11) /* 1=code segment 0=data segment */
+#define DESC_C_MASK (1 << 10) /* code: conforming */
+#define DESC_R_MASK (1 << 9) /* code: readable */
-#define DESC_E_MASK (1 << 10)
-#define DESC_W_MASK (1 << 9)
+#define DESC_E_MASK (1 << 10) /* data: expansion direction */
+#define DESC_W_MASK (1 << 9) /* data: writable */
+
+#define DESC_TSS_BUSY_MASK (1 << 9)
/* eflags masks */
#define CC_C 0x0001