3 #define SEG_TYPE_SYSTEM 0
4 #define SEG_TYPE_CODE 0x00001800
5 #define SEG_TYPE_DATA 0x00001000
6 #define SEG_TYPE_TSS 0x00000100
7 #define SEG_TYPE_INTR 0x00000e00
8 #define SEG_TYPE_TRAP 0x00000f00
10 #define SEG_ACCESSED 0x00000100
11 #define SEG_PRESENT 0x00008000
12 #define SEG_AVL 0x00100000
13 #define SEG_GRAN 0x00800000
15 /* data segment type flags */
16 #define SEG_WR 0x00000200
17 #define SEG_EXPDN 0x00000400
18 #define SEG_BIG 0x00400000
19 /* code segment type flags */
20 #define SEG_RD 0x00000200
21 #define SEG_CONFORM 0x00000400
22 #define SEG_DEF 0x00400000
25 void desc_seg(struct desc *desc, int type, uint32_t base, uint32_t limit, int dpl)
27 if(type == SEG_NULL) {
28 desc->d[0] = desc->d[1] = 0;
32 desc->d[0] = (limit & 0xffff) | (base << 16);
33 desc->d[1] = ((base >> 16) & 0xff) | (type << 8) | SEG_PRESENT | (dpl << 13);
34 desc->d[1] |= (base & 0xff000000) | (limit & 0xf0000) | SEG_AVL | SEG_GRAN;
38 desc->d[1] |= (3 << 11) | SEG_DEF | SEG_RD;
42 desc->d[1] |= (2 << 11) | SEG_WR;