global int_syscall_handler

[extern syscall_exit]
[extern syscall_write]
[extern syscall_read]
[extern syscall_readdir]
[extern syscall_execve]
[extern syscall_open]
[extern syscall_close]
[extern syscall_fstat]
[extern syscall_isatty]
[extern syscall_lseek]
[extern syscall_sbrk]
[extern syscall_unhandled]

[bits 32]
int_syscall_handler:

 cli

    push ebx
    push ecx
    push edx

    cmp eax, 60
    je call_exit

    cmp eax, 61
    je call_write

    cmp eax, 62
    je call_read

    cmp eax, 63
    je call_readdir

    cmp eax, 64
    je call_execve

    cmp eax, 65
    je call_open

    cmp eax, 66
    je call_close

    cmp eax, 67
    je call_fstat

    cmp eax, 68
    je call_isatty

    cmp eax, 69
    je call_lseek

    cmp eax, 70
    je call_sbrk

    push eax
    jmp call_unhandled


done:

    mov ebx,eax 

    mov al, 0x20   ;Port number AND command number to Acknowledge IRQ
    out 0x20, al     ;Acknowledge IRQ, so we keep getting interrupts

    mov eax,ebx 


done_blocking:

    pop ebx
    pop ecx
    pop edx

    mov ebx,eax 

    sti

    iret           ;Interrupt-Return

call_write:
    call syscall_write
    jmp done

call_open:
    call syscall_open
    jmp done

call_readdir:
    call syscall_readdir
    jmp done

call_close:
    call syscall_close
    jmp done

call_fstat:
    call syscall_fstat
    jmp done

call_isatty:
    call syscall_isatty
    jmp done

call_lseek:
    call syscall_lseek
    jmp done

call_sbrk:
    call syscall_sbrk
    jmp done

call_exit:
    call syscall_exit
    jmp done

call_unhandled:
    call syscall_unhandled
    jmp done ;this should never be called, since unhandled causes kernel panic


    ;;; THIS CALLS NEED REENABLE INTERRUPTS BEFORE calling workers
call_read:

    mov al, 0x20   ;Port number AND command number to Acknowledge IRQ
    out 0x20, al     ;Acknowledge IRQ, so we keep getting interrupts
    sti

    call syscall_read

    jmp done_blocking

call_execve:

    mov al, 0x20   ;Port number AND command number to Acknowledge IRQ
    out 0x20, al     ;Acknowledge IRQ, so we keep getting interrupts
    sti

    call syscall_execve
    jmp $ ; this should never return TODO: pop stack!?