path: root/src/kernel/mem/gdt.h

#ifndef DEF_GDT_H
#define DEF_GDT_H

#include <types.h>

struct gdt_entry {
	uint16_t limit_low;
	uint16_t base_low;
	uint8_t base_middle;
	uint8_t access;
	uint8_t granularity;
	uint8_t base_high;
} __attribute__((packed));

struct gdt_ptr {
	uint16_t limit;
	uint32_t base;
} __attribute__((packed));

struct tss_entry {
	uint32_t prev_tss;   // The previous TSS - if we used hardware task switching this would form a linked list.
	uint32_t esp0;       // The stack pointer to load when we change to kernel mode.
	uint32_t ss0;        // The stack segment to load when we change to kernel mode.
	uint32_t esp1;       // Unused...
	uint32_t ss1;
	uint32_t esp2;
	uint32_t ss2;
	uint32_t cr3;
	uint32_t eip;
	uint32_t eflags;
	uint32_t eax;
	uint32_t ecx;
	uint32_t edx;
	uint32_t ebx;
	uint32_t esp;
	uint32_t ebp;
	uint32_t esi;
	uint32_t edi;
	uint32_t es;         // The value to load into ES when we change to kernel mode.
	uint32_t cs;         // The value to load into CS when we change to kernel mode.
	uint32_t ss;         // The value to load into SS when we change to kernel mode.
	uint32_t ds;         // The value to load into DS when we change to kernel mode.
	uint32_t fs;         // The value to load into FS when we change to kernel mode.
	uint32_t gs;         // The value to load into GS when we change to kernel mode.
	uint32_t ldt;        // Unused...
	uint16_t trap;
	uint16_t iomap_base;
} __attribute__((packed));

void gdt_init();
void gdt_setKernelStack(uint32_t esp0);

#endif