[BITS 32]

[GLOBAL isr_stub_table]
[GLOBAL irq_stub_table]
[GLOBAL interrupt_entry]

extern interrupt_dispatcher

section .text

; ============================================================
;                COMMON INTERRUPT ENTRY
; ============================================================

interrupt_entry:

    ; Stack already contains:
    ;   err_code
    ;   int_no
    ;   eip
    ;   cs
    ;   eflags

    pusha ; eax, ecx, edx, ebx, esp, ebp, esi, edi

    ;push ds
    ;push es
    ;push fs
    ;push gs
    
    push gs
    push fs
    push es
    push ds


    mov ax, 0x10 ; load kernel data selector
    mov ds, ax
    mov es, ax
    mov fs, ax
    mov gs, ax

    push esp ; pass pointer to registers_t
    call interrupt_dispatcher
    add esp, 4

    pop gs
    pop fs
    pop es
    pop ds

    popa

    add esp, 8 ; remove int_no + err_code

    iret


; ============================================================
;                     IRQ STUBS
; ============================================================

%macro IRQ 1
irq_stub_%+%1:
    push dword 0               ; fake error code
    push dword (32 + %1)       ; vector number
    jmp interrupt_entry
%endmacro

IRQ 0
IRQ 1
IRQ 2
IRQ 3
IRQ 4
IRQ 5
IRQ 6
IRQ 7
IRQ 8
IRQ 9
IRQ 10
IRQ 11
IRQ 12
IRQ 13
IRQ 14
IRQ 15

irq_stub_table:
%assign i 0
%rep 16
    dd irq_stub_%+i
%assign i i+1
%endrep


; ============================================================
;                    EXCEPTION STUBS
; ============================================================

%macro ISR_NOERR 1
isr_stub_%+%1:
    push dword 0               ; fake error code
    push dword %1              ; interrupt number
    jmp interrupt_entry
%endmacro

%macro ISR_ERR 1
isr_stub_%+%1:
    push dword %1              ; interrupt number
    jmp interrupt_entry
%endmacro


; Exceptions 0–31

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

isr_stub_table:
%assign i 0
%rep 32
    dd isr_stub_%+i
%assign i i+1
%endrep