source: xtideuniversalbios/trunk/XTIDE_Universal_BIOS/Src/Initialization/DetectDrives.asm@ 191

; 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:
    mov     si,g_szDetect
    call    .DetectDrives_WithIDEVARS       ; Detect Master and Slave
    add     bp, BYTE IDEVARS_size           ; Point to next IDEVARS
    loop    .DriveDetectLoop

%ifdef MODULE_SERIAL
    test    BYTE [es:BDA.bKBFlgs1], 8       ; alt key depressed
    jz      .done
    mov     bp, ROMVARS.ideVarsSerialAuto
    mov     si,g_szSerial
;;; fall-through        
%else
    ret
%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
        
    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:
;       Nothing
;   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     DetectPrint_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 .InvalidAtaInfo
    call    BootInfo_CreateForHardDisk
    jmp     DetectPrint_DriveNameFromBootnfoInESBX
.InvalidAtaInfo:
    jmp     DetectPrint_DriveNotFound