source: xtideuniversalbios/trunk/XTIDE_Universal_BIOS/Src/Handlers/Int13h/AH0h_HReset.asm @ 259

; Project name  :   XTIDE Universal BIOS
; Description   :   Int 13h function AH=0h, Disk Controller Reset.

; Section containing code
SECTION .text

;--------------------------------------------------------------------
; Int 13h function AH=0h, Disk Controller Reset.
;
; AH0h_HandlerForDiskControllerReset
;   Parameters:
;       DL:     Translated Drive number (ignored so all drives are reset)
;               If bit 7 is set all hard disks and floppy disks reset.
;       DS:DI:  Ptr to DPT (in RAMVARS segment)
;       SS:BP:  Ptr to IDEPACK
;   Returns with INTPACK:
;       AH:     Int 13h return status (from drive requested in DL)
;       CF:     0 if succesfull, 1 if error
;--------------------------------------------------------------------
ALIGN JUMP_ALIGN
AH0h_HandlerForDiskControllerReset:
    eMOVZX  bx, dl                      ; Copy requested drive to BL, zero BH to assume no errors
    call    ResetFloppyDrivesWithInt40h

%ifdef MODULE_SERIAL_FLOPPY
;
; "Reset" emulatd serial floppy drives, if any.  There is nothing to actually do for this reset,
; but record the proper error return code if one of these floppy drives is the drive requested.
;
    call    RamVars_UnpackFlopCntAndFirstToAL
    cbw                                                 ; Clears AH (there are flop drives) or ffh (there are not)
                                                        ; Either AH has success code (flop drives are present)
                                                        ; or it doesn't matter because we won't match drive ffh

    cwd                                                 ; clears DX (there are flop drives) or ffffh (there are not)

    adc     dl, al                                      ; second drive (CF set) if present
                                                        ; If no drive is present, this will result in ffh which 
                                                        ; won't match a drive
    call    BackupErrorCodeFromTheRequestedDriveToBH
    mov     dl, al                                      ; We may end up doing the first drive twice (if there is
    call    BackupErrorCodeFromTheRequestedDriveToBH    ; only one drive), but doing it again is not harmful.
%endif

    test    bl, bl                                      ; If we were called with a floppy disk, then we are done,
    jns     SHORT .SkipHardDiskReset                    ; don't do hard disks.
        
    call    ResetForeignHardDisks
    call    AH0h_ResetHardDisksHandledByOurBIOS
.SkipHardDiskReset:
    mov     ah, bh
    jmp     Int13h_ReturnFromHandlerAfterStoringErrorCodeFromAH


;--------------------------------------------------------------------
; ResetFloppyDrivesWithInt40h
;   Parameters:
;       BL:     Requested drive (DL when entering AH=00h)
;   Returns:
;       BH:     Error code from requested drive (if available)
;   Corrupts registers:
;       AX, DL, DI
;--------------------------------------------------------------------
ALIGN JUMP_ALIGN
ResetFloppyDrivesWithInt40h:
    call    GetDriveNumberForForeignBiosesToDL
    and     dl, 7Fh                     ; Clear hard disk bit
    xor     ah, ah                      ; Disk Controller Reset
    int     BIOS_DISKETTE_INTERRUPT_40h
    jmp     SHORT BackupErrorCodeFromTheRequestedDriveToBH


;--------------------------------------------------------------------
; ResetForeignHardDisks
;   Parameters:
;       BL:     Requested drive (DL when entering AH=00h)
;       DS:     RAMVARS segment
;   Returns:
;       BH:     Error code from requested drive (if available)
;   Corrupts registers:
;       AX, DL, DI
;--------------------------------------------------------------------
ALIGN JUMP_ALIGN
ResetForeignHardDisks:
    call    GetDriveNumberForForeignBiosesToDL
    xor     ah, ah                      ; Disk Controller Reset
    call    Int13h_CallPreviousInt13hHandler
;;; fall-through to BackupErrorCodeFromTheRequestedDriveToBH


;--------------------------------------------------------------------
; BackupErrorCodeFromTheRequestedDriveToBH
;   Parameters:
;       AH:     Error code from the last resetted drive
;       DL:     Drive last resetted
;       BL:     Requested drive (DL when entering AH=00h)
;   Returns:
;       BH:     Backuped error code
;   Corrupts registers:
;       Nothing
;--------------------------------------------------------------------
ALIGN JUMP_ALIGN
BackupErrorCodeFromTheRequestedDriveToBH:
    cmp     dl, bl              ; Requested drive?
    eCMOVE  bh, ah
    ret
        

;--------------------------------------------------------------------
; GetDriveNumberForForeignBiosesToDL
;   Parameters:
;       BL:     Requested drive (DL when entering AH=00h)
;       DS:     RAMVARS segment
;   Returns:
;       DL:     BL if foreign drive
;               80h if our drive
;   Corrupts registers:
;       DI
;--------------------------------------------------------------------
ALIGN JUMP_ALIGN
GetDriveNumberForForeignBiosesToDL:
    mov     dl, bl
    call    RamVars_IsDriveHandledByThisBIOS
    jc      SHORT .Return               ; Return what was in BL unmodified
    mov     dl, 80h
.Return:
    ret


;--------------------------------------------------------------------
; AH0h_ResetHardDisksHandledByOurBIOS
;   Parameters:
;       BL:     Requested drive (DL when entering AH=00h)
;       DS:     RAMVARS segment
;       SS:BP:  Ptr to IDEPACK
;   Returns:
;       BH:     Error code from requested drive (if available)
;   Corrupts registers:
;       AX, CX, DX, SI, DI
;--------------------------------------------------------------------
ALIGN JUMP_ALIGN
AH0h_ResetHardDisksHandledByOurBIOS:
    mov     dx, [RAMVARS.wDrvCntAndFirst]   ; DL = drive number, DH = drive count
    test    dh, dh
    jz      SHORT .AllDrivesReset       ; Return if no drives
    add     dh, dl                      ; DH = one past last drive to reset
ALIGN JUMP_ALIGN
.DriveResetLoop:
    call    AHDh_ResetDrive
    call    .BackupErrorCodeFromMasterOrSlaveToBH
    inc     dx
    cmp     dl, dh                      ; All done?
    jb      SHORT .DriveResetLoop       ;  If not, reset next drive
.AllDrivesReset:
    ret

                
;--------------------------------------------------------------------
; .BackupErrorCodeFromMasterOrSlaveToBH
;   Parameters:
;       AH:     Error code for drive DL reset
;       BL:     Requested drive (DL when entering AH=00h)
;       DL:     Drive just resetted
;       DS:     RAMVARS segment
;   Returns:
;       BH:     Backuped error code
;       DL:     Incremented if next drive is slave drive
;               (=already resetted)
;   Corrupts registers:
;       CX, DI
;--------------------------------------------------------------------
ALIGN JUMP_ALIGN
.BackupErrorCodeFromMasterOrSlaveToBH:
    call    BackupErrorCodeFromTheRequestedDriveToBH
    call    GetBasePortToCX             ; Load base port for resetted drive
    push    cx
    inc     dx                          ; DL to next drive
    call    GetBasePortToCX
    pop     di
    cmp     cx, di                      ; Next drive is from same controller?
    je      SHORT BackupErrorCodeFromTheRequestedDriveToBH
.NoMoreDrivesOrNoSlaveDrive:
    dec     dx
    ret

        
;--------------------------------------------------------------------
; GetBasePortToCX
;   Parameters:
;       DL:     Drive number
;       DS:     RAMVARS segment
;   Returns:
;       CX:     Base port address
;       CF:     Set if valid drive number
;               Cleared if invalid drive number
;   Corrupts registers:
;       DI
;--------------------------------------------------------------------
ALIGN JUMP_ALIGN
GetBasePortToCX:
    xchg    cx, bx
    xor     bx, bx
    call    FindDPT_ForDriveNumber
    mov     bl, [di+DPT.bIdevarsOffset]
    mov     bx, [cs:bx+IDEVARS.wPort]
    xchg    bx, cx
    ret