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#include "gdt.h"
struct __attribute__((packed)) Pointer {
uint16_t limit;
uint32_t base;
};
static struct SegmentDescriptor_t segments[8] __attribute__((aligned(32)));
void
gdt_install()
{
const struct Pointer ptr = {sizeof(segments) - 1, (unsigned)&segments};
SegmentDescriptor(&segments[0], 0, 0, 0); /* null segment */
SegmentDescriptor(&segments[2], 0, 0xffffffff, 0x9a); /* ktext segment */
SegmentDescriptor(&segments[3], 0, 0xffffffff, 0x92); /* kdata segment */
__asm__("lgdt (%0)" : : "a"(&ptr));
/* load the kernel data segment */
__asm__("mov %0, %%ds; mov %0, %%es; mov %0, %%fs; mov %0, %%gs; mov %0, %%ss" : : "ax"(kdataDescriptor));
/* load the kernel code segment */
__asm__("ljmp %0, $1f\n1:" : : "i"(ktextDescriptor));
}
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