source: xtideuniversalbios/trunk/XTIDE_Universal_BIOS/Src/Initialization/Initialize.asm @ 258

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

; 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
    push    es
    push    ds
    ePUSHA

    LOAD_BDA_SEGMENT_TO es, ax
    sti                                     ; Enable interrupts
    test    BYTE [es: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     al, BIOS_BOOT_LOADER_INTERRUPT_19h
    mov     si, Int19h_BootLoaderHandler
    call    Interrupts_InstallHandlerToVectorInALFromCSSI

.SkipRomInitialization:
    ePOPA
    pop     ds
    pop     es
    popf
    retf


;--------------------------------------------------------------------
; Initializes the BIOS variables and detects IDE drives.
;
; Initialize_AndDetectDrives
;   Parameters:
;       ES:     BDA Segment
;   Returns:
;       DS:     RAMVARS segment
;   Corrupts registers:
;       All
;--------------------------------------------------------------------
Initialize_AndDetectDrives:
    call    BootMenuPrint_InitializeDisplayContext
    call    DetectPrint_RomFoundAtSegment
    call    RamVars_Initialize
    call    Interrupts_InitializeInterruptVectors
    call    DetectDrives_FromAllIDEControllers
    ; 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    RamVars_IsDriveHandledByThisBIOS
    jc      SHORT .FindForDrive81h  ; Store nothing if not our drive
    call    FindDPT_ForDriveNumber  ; DPT to DS:DI
    mov     [es:HD0_DPT_POINTER_41h*4], di
    mov     [es:HD0_DPT_POINTER_41h*4+2], ds
.FindForDrive81h:
    inc     dx
    call    RamVars_IsDriveHandledByThisBIOS
    jc      SHORT .ResetDetectedDrives
    call    FindDPT_ForDriveNumber
    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_ResetHardDisksHandledByOurBIOS
    add     sp, BYTE EXTRA_BYTES_FOR_INTPACK
    ret