source: xtideuniversalbios/trunk/XTIDE_Universal_BIOS/Src/Initialization/DetectDrives.asm@ 201

; 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
    mov     si, g_szDetect                  ; Setup standard print string
%ifdef MODULE_SERIAL
    cmp     byte [cs:bp+IDEVARS.bDevice], DEVICE_SERIAL_PORT
    jnz     .DriveNotSerial                 ; Special print string for serial drives
    mov     si, g_szDetectCOM
.DriveNotSerial:
%endif
    call    .DetectDrives_WithIDEVARS       ; Detect Master and Slave
    add     bp, BYTE IDEVARS_size           ; Point to next IDEVARS
    loop    .DriveDetectLoop
        
%ifdef MODULE_SERIAL
    call    FindDPT_ToDSDIforSerialDevice   ; Did we already find any serial drives? 
    jc      .done                           ; Yes, do not scan
    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
    jz      .done                           
    mov     bp, ROMVARS.ideVarsSerialAuto   ; Point to our special IDEVARS sructure, just for serial scans
    mov     si, g_szDetectCOMAuto           ; Special, special print string for serial drives during a scan
;;; fall-through                    
%else
    ret
%endif

%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

;--------------------------------------------------------------------
; Detects IDE hard disks by using information from IDEVARS.
;
; DetectDrives_WithIDEVARS
;   Parameters:
;       CS:BP:      Ptr to IDEVARS
;       DS:         RAMVARS segment
;       ES:         Zero (BDA segment)
;       SI:         Ptr to template string
;   Returns:
;       Nothing
;   Corrupts registers:
;       AX, BX, DX, SI, DI
;--------------------------------------------------------------------
.DetectDrives_WithIDEVARS:
    push    cx

    push    si      
    mov     ax, g_szMaster
    mov     bh, MASK_DRVNHEAD_SET                               ; Select Master drive
    call    StartDetectionWithDriveSelectByteInBHandStringInAX  ; Detect and create DPT + BOOTNFO
    pop     si

%ifdef MODULE_SERIAL
;
; This block of code checks to see if we found a master during a serial drives scan.  If no master
; was found, there is no point in scanning for a slave as the server will not return a slave without a master,
; as there is very little point given the drives are emulated.  Performing the slave scan will take 
; time to rescan all the COM port and baud rate combinations.
;
    jnc     .masterFound
    pop     cx
    jcxz    .done       ; note that CX will only be zero after the .DriveDetectLoop, indicating a serial scan
    push    cx
.masterFound:
%endif
        
    mov     ax, g_szSlave
    mov     bh, MASK_DRVNHEAD_SET | FLG_DRVNHEAD_DRV
    call    StartDetectionWithDriveSelectByteInBHandStringInAX
    pop     cx
        
.done:  
    ret

        
;--------------------------------------------------------------------
; StartDetectionWithDriveSelectByteInBHandStringInAX
;   Parameters:
;       AX:     Offset to "Master" or "Slave" string
;       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:     Set on failure, Clear on success
;               Note that this is set in the last thing both cases
;               do: printing the drive name, or printing "Not Found"
;   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


;--------------------------------------------------------------------
; 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

;--------------------------------------------------------------------
; DetectDrives_DriveNotFound
;   Parameters:
;       Nothing
;   Returns:
;       CF:     Set (from BootMenuPrint_NullTerminatedStringFromCSSIandSetCF)
;   Corrupts registers:
;       AX, SI
;--------------------------------------------------------------------
DetectDrives_DriveNotFound:     
    mov     si, g_szNotFound
    jmp     BootMenuPrint_NullTerminatedStringFromCSSIandSetCF