source: xtideuniversalbios/trunk/XTIDE_Universal_BIOS/Src/Handlers/Int19h/Int19hReset.asm @ 595

; Project name  :   XTIDE Universal BIOS
; Description   :   Int 19h Handler (Boot Loader).

;
; XTIDE Universal BIOS and Associated Tools
; Copyright (C) 2009-2010 by Tomi Tilli, 2011-2013 by XTIDE Universal BIOS Team.
;
; This program is free software; you can redistribute it and/or modify
; it under the terms of the GNU General Public License as published by
; the Free Software Foundation; either version 2 of the License, or
; (at your option) any later version.
;
; This program is distributed in the hope that it will be useful,
; but WITHOUT ANY WARRANTY; without even the implied warranty of
; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
; GNU General Public License for more details.
; Visit http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
;

; Section containing code
SECTION .text

;--------------------------------------------------------------------
; INT 19h handler that properly reboots the computer when
; INT 19h is called.
;
; Int19hReset_Handler
;   Parameters:
;       Nothing
;   Returns:
;       Never returns (reboots computer)
;--------------------------------------------------------------------
Int19hReset_Handler:
    ; Try to boot from drive A.
    ; This is needed if INT 19h is used to launch booter games while
    ; preserving interrupt vector table (for example to hook interrupt 10h)
    xor     dx, dx      ; Drive 00h
    call    BootSector_LoadFirstSectorFromDriveDL
    jc      SHORT .Reboot

    xor     ax, ax
    mov     ds, ax
%ifdef USE_386
    mov     fs, ax
    mov     gs, ax
%endif
    cmp     WORD [bx+510], 0AA55h   ; Valid boot sector?
    jne     SHORT .Reboot
    push    es                      ; Zero
    push    bx
    retf

    ; Do warm reset since boot from floppy drive failed
.Reboot:
    mov     ax, BOOT_FLAG_WARM              ; Skip memory tests
    jmp     Reboot_ComputerWithBootFlagInAX