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#ifndef GDT_H
#define GDT_H
#include <stdint.h>
#define SEG_DESCTYPE(x) ((x) << 0x04)
#define SEG_PRES(x) ((x) << 0x07)
#define SEG_SAVL(x) ((x) << 0x0C)
#define SEG_LONG(x) ((x) << 0x0D)
#define SEG_SIZE(x) ((x) << 0x0E)
#define SEG_GRAN(x) ((x) << 0x0F)
#define SEG_PRIV(x) (((x) & 0x03) << 0x05)
#define SEG_DATA_RD 0x00
#define SEG_DATA_RDA 0x01
#define SEG_DATA_RDWR 0x02
#define SEG_DATA_RDWRA 0x03
#define SEG_DATA_RDEXPD 0x04
#define SEG_DATA_RDEXPDA 0x05
#define SEG_DATA_RDWREXD 0x06
#define SEG_DATA_RDWREXDA 0x07
#define SEG_CODE_EX 0x08
#define SEG_CODE_EXA 0x09
#define SEG_CODE_EXRD 0x0A
#define SEG_CODE_EXRDA 0x0B
#define SEG_CODE_EXC 0x0C
#define SEG_CODE_EXCA 0x0D
#define SEG_CODE_EXRDC 0x0E
#define SEG_CODE_EXRDCA 0x0F
#define GDT_CODE_PL0 SEG_DESCTYPE(1) | SEG_PRES(1) | SEG_SAVL(0) | \
SEG_LONG(0) | SEG_SIZE(1) | SEG_GRAN(1) | \
SEG_PRIV(0) | SEG_CODE_EXRD
#define GDT_DATA_PL0 SEG_DESCTYPE(1) | SEG_PRES(1) | SEG_SAVL(0) | \
SEG_LONG(0) | SEG_SIZE(1) | SEG_GRAN(1) | \
SEG_PRIV(0) | SEG_CODE_RDWR
#define GDT_CODE_PL3 SEG_DESCTYPE(1) | SEG_PRES(1) | SEG_SAVL(0) | \
SEG_LONG(0) | SEG_SIZE(1) | SEG_GRAN(1) | \
SEG_PRIV(3) | SEG_DATA_EXRD
#define GDT_DATA_PL3 SEG_DESCTYPE(1) | SEG_PRES(1) | SEG_SAVL(0) | \
SEG_LONG(0) | SEG_SIZE(1) | SEG_GRAN(1) | \
SEG_PRIV(3) | SEG_DATA_RDWR
struct gdt {
uint16_t size;
uint32_t offset;
} __attribute__((packed));
void flush_gdt(void);
uint64_t create_descriptor(uint32_t base, uint32_t limit, uint16_t flag) {
uint64_t descriptor;
descriptor = limit & 0x000F0000;
descriptor |= (flag << 8) & 0x00F0FF00;
descriptor |= (base >> 16) & 0x000000FF;
descriptor |= base & 0xFF000000;
descriptor <<= 32;
descriptor |= base << 16;
descriptor |= limit & 0x0000FFFF;
return descriptor;
}
#endif
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