#pragma once

#define STA_X 0x8 // Executable segment
#define STA_W 0x2 // Writeable (non-executable segments)
#define STA_R 0x2 // Readable (executable segments)

// System segment type bits
#define STS_T32A 0x9 // Available 32-bit TSS
#define STS_IG32 0xE // 32-bit Interrupt Gate
#define STS_TG32 0xF // 32-bit Trap Gate

#define DPL_USER 3

#define FL_IF 0x00000200

#define SEG_KCODE 1
#define SEG_KDATA 2
#define SEG_UCODE 3
#define SEG_UDATA 4
#define SEG_TSS 5

#define SEG_ASM(type, base, lim)                                               \
    .word(((lim) >> 12) & 0xffff), ((base) & 0xffff);                          \
    .byte(((base) >> 16) & 0xff), (0x90 | (type)),                             \
        (0xC0 | (((lim) >> 28) & 0xf)), (((base) >> 24) & 0xff)

#define USER_BASE 0x400000       // 4 MB
#define USER_STACK_BASE 0xf00000 // 15 MB
#define KERN_STACK_BASE 0x90000

#ifndef __ASSEMBLER__
#include "kernel/mem.h"
typedef unsigned uint;
typedef unsigned short ushort;

struct taskstate {
    uint link;  // Old ts selector
    uint esp0;  // Stack pointers and segment selectors
    ushort ss0; //   after an increase in privilege level
    ushort padding1;
    uint *esp1;
    ushort ss1;
    ushort padding2;
    uint *esp2;
    ushort ss2;
    ushort padding3;
    void *cr3; // Page directory base
    uint *eip; // Saved state from last task switch
    uint eflags;
    uint eax; // More saved state (registers)
    uint ecx;
    uint edx;
    uint ebx;
    uint *esp;
    uint *ebp;
    uint esi;
    uint edi;
    ushort es; // Even more saved state (segment selectors)
    ushort padding4;
    ushort cs;
    ushort padding5;
    ushort ss;
    ushort padding6;
    ushort ds;
    ushort padding7;
    ushort fs;
    ushort padding8;
    ushort gs;
    ushort padding9;
    ushort ldt;
    ushort padding10;
    ushort t;    // Trap on task switch
    ushort iomb; // I/O map base address
};

void load_gdt();
void switchuvm(struct taskstate *tss, void *esp, pde_t *pgdir);
#endif