Espresso/isr.asm

[BITS 32]
[GLOBAL isr_stub_table]
[GLOBAL irq_stub_table]
extern irq_handler     ; C function

section .text

; --------------------------------------------
; ------------------- IRQs -------------------
; --------------------------------------------

%macro irq_stub 1
irq_stub_%+%1:
    pusha
    push ds
    push es
    push fs
    push gs

    mov ax, 0x10
    mov ds, ax
    mov es, ax
    mov fs, ax
    mov gs, ax

    push dword %1        ; Push IRQ number
    call irq_handler
    add esp, 4           ; Clean up stack

    ; Send EOI
    mov al, 0x20
    mov bl, %1
    cmp bl, 8
    jb .skip_slave_eoi
    out 0xA0, al
.skip_slave_eoi:
    out 0x20, al

    pop gs
    pop fs
    pop es
    pop ds
    popa
    iret
%endmacro


; Define 16 IRQ stubs
irq_stub 0
irq_stub 1
irq_stub 2
irq_stub 3
irq_stub 4
irq_stub 5
irq_stub 6
irq_stub 7
irq_stub 8
irq_stub 9
irq_stub 10
irq_stub 11
irq_stub 12
irq_stub 13
irq_stub 14
irq_stub 15

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

; --------------------------------------------
; ------------------- ISRs -------------------
; --------------------------------------------

; Common exception handler entry point
isr_common_handler:
    pusha                  ; Push general-purpose registers
    push ds
    push es
    push fs
    push gs

    ; Load known-good segment selectors
    mov ax, 0x10
    mov ds, ax
    mov es, ax
    mov fs, ax
    mov gs, ax

    ; Print exception number and error code
    ; You can insert direct port writes or call kernel logging function here
    ; For now, just hang
.halt:
    cli
    hlt
    jmp .halt

    ; If you want to later restore:
    pop gs
    pop fs
    pop es
    pop ds
    popa
    add esp, 8             ; clean up int_no + err_code
    iret

; Macro: for exceptions with error code
%macro isr_err_stub 1
isr_stub_%+%1:
    cli
    push dword %1          ; interrupt number
    jmp isr_common_handler
%endmacro

; Macro: for exceptions without error code
%macro isr_no_err_stub 1
isr_stub_%+%1:
    cli
    push dword 0           ; fake error code
    push dword %1          ; interrupt number
    jmp isr_common_handler
%endmacro

; Define all 32 exception stubs
isr_no_err_stub 0
isr_no_err_stub 1
isr_no_err_stub 2
isr_no_err_stub 3
isr_no_err_stub 4
isr_no_err_stub 5
isr_no_err_stub 6
isr_no_err_stub 7
isr_err_stub    8
isr_no_err_stub 9
isr_err_stub    10
isr_err_stub    11
isr_err_stub    12
isr_err_stub    13
isr_err_stub    14
isr_no_err_stub 15
isr_no_err_stub 16
isr_err_stub    17
isr_no_err_stub 18
isr_no_err_stub 19
isr_no_err_stub 20
isr_no_err_stub 21
isr_no_err_stub 22
isr_no_err_stub 23
isr_no_err_stub 24
isr_no_err_stub 25
isr_no_err_stub 26
isr_no_err_stub 27
isr_no_err_stub 28
isr_no_err_stub 29
isr_err_stub    30
isr_no_err_stub 31

; Create jump table
isr_stub_table:
%assign i 0
%rep 32
    dd isr_stub_%+i
%assign i i+1
%endrep