source: xtideuniversalbios/trunk/XTIDE_Universal_BIOS/Src/Initialization/DetectDrives.asm@ 252

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

; Section containing code
SECTION .text

;--------------------------------------------------------------------
; Detects all IDE hard disks to be controlled by this BIOS.
;
; DetectDrives_FromAllIDEControllers
;   Parameters:
;       DS:     RAMVARS segment
;       ES:     BDA segment (zero)
;   Returns:
;       Nothing
;   Corrupts registers:
;       All (not segments)
;--------------------------------------------------------------------
DetectDrives_FromAllIDEControllers:
    call    RamVars_GetIdeControllerCountToCX
    mov     bp, ROMVARS.ideVars0            ; CS:BP now points to first IDEVARS

.DriveDetectLoop:                           ; Loop through IDEVARS
    push    cx

    mov     cx, g_szDetectMaster
    mov     bh, MASK_DRVNHEAD_SET                               ; Select Master drive
    call    StartDetectionWithDriveSelectByteInBHandStringInAX  ; Detect and create DPT + BOOTNFO

    mov     cx, g_szDetectSlave
    mov     bh, MASK_DRVNHEAD_SET | FLG_DRVNHEAD_DRV
    call    StartDetectionWithDriveSelectByteInBHandStringInAX

    pop     cx

    add     bp, BYTE IDEVARS_size           ; Point to next IDEVARS

%ifdef MODULE_SERIAL
    jcxz    .done                           ; Set to zero on .ideVarsSerialAuto iteration (if any)
%endif

    loop    .DriveDetectLoop

%ifdef MODULE_SERIAL
;
; if serial drive detected, do not scan (avoids duplicate drives and isn't needed - we already have a connection)
;
    call    FindDPT_ToDSDIforSerialDevice
    jc      .done

    mov     bp, ROMVARS.ideVarsSerialAuto   ; Point to our special IDEVARS structure, just for serial scans

    mov     al,[cs:ROMVARS.wFlags]          ; Configurator set to always scan?
    or      al,[es:BDA.bKBFlgs1]            ; Or, did the user hold down the ALT key?
    and     al,8                            ; 8 = alt key depressed, same as FLG_ROMVARS_SERIAL_ALWAYSDETECT
    jnz     .DriveDetectLoop
%endif

.done:
    ret

%if FLG_ROMVARS_SERIAL_SCANDETECT != 8
    %error "DetectDrives is currently coded to assume that FLG_ROMVARS_SERIAL_SCANDETECT is the same bit as the ALT key code in the BDA.  Changes in the code will be needed if these values are no longer the same."
%endif


;--------------------------------------------------------------------
; StartDetectionWithDriveSelectByteInBHandStringInAX
;   Parameters:
;       BH:     Drive Select byte for Drive and Head Register
;       CX:     Offset to "Master" or "Slave" string
;       CS:BP:  Ptr to IDEVARS for the drive
;       DS:     RAMVARS segment
;       ES:     Zero (BDA segment)
;   Returns:
;       None
;   Corrupts registers:
;       AX, BX, CX, DX, SI, DI
;--------------------------------------------------------------------
StartDetectionWithDriveSelectByteInBHandStringInAX:
    call    DetectPrint_StartDetectWithMasterOrSlaveStringInAXandIdeVarsInCSBP
    ; Fall to .ReadAtaInfoFromHardDisk

;--------------------------------------------------------------------
; .ReadAtaInfoFromHardDisk
;   Parameters:
;       BH:     Drive Select byte for Drive and Head Register
;       CS:BP:  Ptr to IDEVARS for the drive
;       DS:     RAMVARS segment
;       ES:     Zero (BDA segment)
;   Returns:
;       CF:     Cleared if ATA-information read successfully
;               Set if any error
;   Corrupts registers:
;       AX, BL, CX, DX, SI, DI
;--------------------------------------------------------------------
.ReadAtaInfoFromHardDisk:
    mov     si, BOOTVARS.rgbAtaInfo     ; ES:SI now points to ATA info location
    push    es
    push    si
    push    bx
    call    Device_IdentifyToBufferInESSIwithDriveSelectByteInBH
    pop     bx
    pop     si
    pop     es
    jnc     SHORT CreateBiosTablesForHardDisk
    ; Fall to .ReadAtapiInfoFromDrive

.ReadAtapiInfoFromDrive:                ; Not yet implemented
    ;call   ReadAtapiInfoFromDrive      ; Assume CD-ROM
    ;jnc    SHORT _CreateBiosTablesForCDROM

    ;jmp    short DetectDrives_DriveNotFound
;;; fall-through instead of previous jmp instruction
;--------------------------------------------------------------------
; DetectDrives_DriveNotFound
;   Parameters:
;       Nothing
;   Returns:
;       CF:     Set (from BootMenuPrint_NullTerminatedStringFromCSSIandSetCF)
;   Corrupts registers:
;       AX, SI
;--------------------------------------------------------------------
DetectDrives_DriveNotFound:
    mov     si, g_szNotFound
    jmp     BootMenuPrint_NullTerminatedStringFromCSSIandSetCF


;--------------------------------------------------------------------
; CreateBiosTablesForHardDisk
;   Parameters:
;       BH:     Drive Select byte for Drive and Head Register
;       CS:BP:  Ptr to IDEVARS for the drive
;       ES:SI   Ptr to ATA information for the drive
;       DS:     RAMVARS segment
;       ES:     BDA/Bootnfo segment
;   Returns:
;       Nothing
;   Corrupts registers:
;       AX, BX, CX, DX, SI, DI
;--------------------------------------------------------------------
CreateBiosTablesForHardDisk:
    call    CreateDPT_FromAtaInformation
    jc      SHORT DetectDrives_DriveNotFound
    call    BootInfo_CreateForHardDisk
    jmp     short DetectPrint_DriveNameFromBootnfoInESBX