; UNRELATED

[GLOBAL gdt_flush]
[GLOBAL tss_flush]

gdt_flush:
  mov eax, [esp+4]
  lgdt [eax]

  mov ax, 0x10
  mov ds, ax
  mov es, ax
  mov fs, ax
  mov gs, ax
  mov ss, ax
  jmp 0x08:.flush

.flush:
  ret

tss_flush:
	mov ax, 0x2B
	ltr ax
	ret

; RELATED

[GLOBAL idt_flush]
idt_flush:
   mov eax, [esp+4]  ; Get the pointer to the IDT, passed as a parameter. 
   lidt [eax]        ; Load the IDT pointer.
   ret

;************************************************************************************

%macro COMMONSTUB 1
[EXTERN idt_%1Handler]
%1_common_stub:
   pusha                    ; Pushes edi,esi,ebp,esp,ebx,edx,ecx,eax

   mov ax, ds               ; Lower 16-bits of eax = ds.
   push eax                 ; save the data segment descriptor

   mov ax, 0x10  ; load the kernel data segment descriptor
   mov ds, ax
   mov es, ax
   mov fs, ax
   mov gs, ax

   mov eax, cr3
   push eax

   call idt_%1Handler
   
   pop eax
   mov cr3, eax

   pop eax        ; reload the original data segment descriptor
   mov ds, ax
   mov es, ax
   mov fs, ax
   mov gs, ax

   popa                     ; Pops edi,esi,ebp...
   add esp, 8     ; Cleans up the pushed error code and pushed ISR number
   sti
   iret 
%endmacro

COMMONSTUB isr
COMMONSTUB irq
COMMONSTUB syscall

;************************************************************************************

%macro ISR_NOERRCODE 1  ; define a macro, taking one parameter
  [GLOBAL isr%1]        ; %1 accesses the first parameter.
  isr%1:
    cli
    push byte 0
    push byte %1
    jmp isr_common_stub
%endmacro

%macro ISR_ERRCODE 1
  [GLOBAL isr%1]
  isr%1:
    cli
    push byte %1
    jmp isr_common_stub
%endmacro

%macro IRQ 2
  [GLOBAL irq%1]
  irq%1:
    cli
    push byte %1	;push irq number
    push byte %2	;push int number
    jmp irq_common_stub
%endmacro

%macro SYSCALL 1
  [GLOBAL syscall%1]
  syscall%1:
    cli
    push byte 0
    push byte %1
    jmp syscall_common_stub
%endmacro

ISR_NOERRCODE 0
ISR_NOERRCODE 1
ISR_NOERRCODE 2
ISR_NOERRCODE 3
ISR_NOERRCODE 4
ISR_NOERRCODE 5
ISR_NOERRCODE 6
ISR_NOERRCODE 7
ISR_ERRCODE 8
ISR_NOERRCODE 9
ISR_ERRCODE 10
ISR_ERRCODE 11
ISR_ERRCODE 12
ISR_ERRCODE 13
ISR_ERRCODE 14
ISR_NOERRCODE 15
ISR_NOERRCODE 16
ISR_NOERRCODE 17
ISR_NOERRCODE 18
ISR_NOERRCODE 19
ISR_NOERRCODE 20
ISR_NOERRCODE 21
ISR_NOERRCODE 22
ISR_NOERRCODE 23
ISR_NOERRCODE 24
ISR_NOERRCODE 25
ISR_NOERRCODE 26
ISR_NOERRCODE 27
ISR_NOERRCODE 28
ISR_NOERRCODE 29
ISR_NOERRCODE 30
ISR_NOERRCODE 31

IRQ	0,	32
IRQ	1,	33
IRQ	2,	34
IRQ	3,	35
IRQ	4,	36
IRQ	5,	37
IRQ	6,	38
IRQ	7,	39
IRQ	8,	40
IRQ	9,	41
IRQ	10,	42
IRQ	11,	43
IRQ	12,	44
IRQ	13,	45
IRQ	14,	46
IRQ	15,	47

SYSCALL 64