source: xtideuniversalbios/trunk/XTIDE_Universal_BIOS/Src/Initialization/Initialize.asm @ 431

; Project name  :   XTIDE Universal BIOS
; Description   :   Functions for initializing the BIOS.

;
; XTIDE Universal BIOS and Associated Tools 
; Copyright (C) 2009-2010 by Tomi Tilli, 2011-2012 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

;--------------------------------------------------------------------
; Initializes the BIOS.
; This function is called from main BIOS ROM search routine.
;
; Initialize_FromMainBiosRomSearch
;   Parameters:
;       Nothing
;   Returns:
;       Nothing
;   Corrupts registers:
;       Nothing
;--------------------------------------------------------------------
Initialize_FromMainBiosRomSearch:       ; unused entrypoint ok
    pushf                               ; To store IF
    push    ds

%ifndef USE_186
    push    ax
    LOAD_BDA_SEGMENT_TO ds, ax
%else
    push    BYTE 0
    pop     ds
%endif

    sti                                 ; Enable interrupts for keystrokes
    test    BYTE [BDA.bKBFlgs1], (1<<2) ; Clears ZF if CTRL is held down
    jnz     SHORT .SkipRomInitialization

    ; Install INT 19h handler (boot loader) where drives are detected
    mov     WORD [BIOS_BOOT_LOADER_INTERRUPT_19h*4], Int19h_BootLoaderHandler
    mov     [BIOS_BOOT_LOADER_INTERRUPT_19h*4+2], cs

.SkipRomInitialization:
%ifndef USE_186
    pop     ax
%endif
    pop     ds
    popf
    retf


;--------------------------------------------------------------------
; Initializes the BIOS variables and detects IDE drives.
;
; Initialize_AndDetectDrives
;   Parameters:
;       ES:     BDA Segment
;   Returns:
;       DS:     RAMVARS segment
;   Corrupts registers:
;       All, except ES
;--------------------------------------------------------------------
Initialize_AndDetectDrives:
    call    DetectPrint_InitializeDisplayContext
    call    DetectPrint_RomFoundAtSegment
    call    RamVars_Initialize
    call    BootVars_Initialize
    call    DetectDrives_FromAllIDEControllers
    call    Interrupts_InitializeInterruptVectors
    ; Fall to .StoreDptPointersToIntVectors

;--------------------------------------------------------------------
; .StoreDptPointersToIntVectors
;   Parameters:
;       DS:     RAMVARS segment
;       ES:     BDA and interrupt vector segment (zero)
;   Returns:
;       Nothing
;   Corrupts registers:
;       DX, DI
;--------------------------------------------------------------------
.StoreDptPointersToIntVectors:
    mov     dl, 80h
    call    FindDPT_ForDriveNumberInDL   ; DPT to DS:DI
    jc      SHORT .FindForDrive81h  ; Store nothing if not our drive
    mov     [es:HD0_DPT_POINTER_41h*4], di
    mov     [es:HD0_DPT_POINTER_41h*4+2], ds
.FindForDrive81h:
    inc     dx
    call    FindDPT_ForDriveNumberInDL
    jc      SHORT .ResetDetectedDrives
    mov     [es:HD1_DPT_POINTER_46h*4], di
    mov     [es:HD1_DPT_POINTER_46h*4+2], ds
    ; Fall to .ResetDetectedDrives

;--------------------------------------------------------------------
; .ResetDetectedDrives
;   Parameters:
;       DS:     RAMVARS segment
;       ES:     BDA and interrupt vector segment (zero)
;   Returns:
;       Nothing
;   Corrupts registers:
;       All, except DS and ES
;--------------------------------------------------------------------
.ResetDetectedDrives:
    call    Idepack_FakeToSSBP
    call    AH0h_ResetAllOurHardDisksAtTheEndOfDriveInitialization
    add     sp, BYTE EXTRA_BYTES_FOR_INTPACK
    ret