; IRQ stubs 0..15 route to C dispatcher irq_dispatch_c(irq)

BITS 32

extern irq_dispatch_c
extern g_abort_to_shell
extern stack_space
extern stack_bottom
extern isr_abort_stack_top
extern ui_return_from_user_task

%macro IRQ_STUB 1
global irq%1
irq%1:
    pushad

    ; Stack overflow tripwire: if the kernel C call stack underflowed (ESP below
    ; stack_bottom), bail out to a known-good stack.
    ; NOTE: when entering from ring 3, the CPU has already switched ESP to
    ; TSS.esp0 = isr_abort_stack_top via the hardware ring switch, so ESP is
    ; always high here in that case.  When entering from ring 0 (interrupt
    ; fires during kernel boot/shell code), ESP is on the C call stack in
    ; [stack_bottom, stack_space]; values below stack_bottom indicate overflow.
    cmp esp, stack_bottom
    jae .stack_ok_%1
    mov dword [g_abort_to_shell], 1
    jmp .do_abort_%1
.stack_ok_%1:

    mov eax, esp
    push eax
    push dword %1
    call irq_dispatch_c
    add esp, 8

    ; If requested, abandon return-to-user and jump back into the shell.
    cmp dword [g_abort_to_shell], 0
    je .no_abort_%1
    mov ax, [esp + 36]
    test ax, 3
    jz .clear_abort_%1
.do_abort_%1:
    mov dword [g_abort_to_shell], 0
    mov ax, 0x10
    mov ds, ax
    mov es, ax
    mov fs, ax
    mov gs, ax
    mov ss, ax
    mov esp, isr_abort_stack_top
    sti
    call ui_return_from_user_task
.halt_%1:
    hlt
    jmp .halt_%1
.clear_abort_%1:
    mov dword [g_abort_to_shell], 0
.no_abort_%1:
    popad
    iretd
%endmacro

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