source: xtideuniversalbios/trunk/XTIDE_Universal_BIOS/Src/VariablesAndDPTs/CompatibleDPT.asm@ 601

; Project name  :   XTIDE Universal BIOS
; Description   :   Functions to handle DPT structs to present drive geometry
;                   to ill behaving applications that want
;                   to read DPT from interrupt vectors 41h and 46h.

;
; XTIDE Universal BIOS and Associated Tools
; Copyright (C) 2009-2010 by Tomi Tilli, 2011-2013 by XTIDE Universal BIOS Team.
;
; This program is free software; you can redistribute it and/or modify
; it under the terms of the GNU General Public License as published by
; the Free Software Foundation; either version 2 of the License, or
; (at your option) any later version.
;
; This program is distributed in the hope that it will be useful,
; but WITHOUT ANY WARRANTY; without even the implied warranty of
; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
; GNU General Public License for more details.
; Visit http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
;

; Section containing code
SECTION .text

;--------------------------------------------------------------------
; CompatibleDPT_CreateToAXSIforDriveDL
;   Parameters:
;       DL:     Drive number (80h or 81h)
;       DS:DI:  Ptr to DPT
;   Returns:
;       AX:SI   Ptr to destination buffer
;   Corrupts registers:
;       CX, DX
;--------------------------------------------------------------------
CompatibleDPT_CreateToAXSIforDriveDL:
    push    es

    call    AccessDPT_GetDeviceControlByteToAL
    xchg    cx, ax                          ; Device control byte to CL
    mov     si, di                          ; DPT now in DS:SI
    call    GetBufferForDrive80hToESDI
    shr     dx, 1
    jnc     SHORT .BufferLoadedToESDI
    add     di, BYTE TRANSLATED_DPT_size    ; For drive 81h
.BufferLoadedToESDI:

    call    FillToESDIusingDPTfromDSSI
    xchg    di, si
    mov     ax, es

    pop     es
    ret


;--------------------------------------------------------------------
; GetTemporaryBufferForDPTEtoESDI
; GetBufferForDrive80hToESDI
;   Parameters:
;       DS:     RAMVARS segment
;   Returns:
;       ES:DI:  Ptr to buffer (in RAMVARS segment)
;   Corrupts registers:
;       Nothing
;--------------------------------------------------------------------
%ifdef MODULE_EBIOS
GetTemporaryBufferForDPTEtoESDI:
    call    GetBufferForDrive80hToESDI
    add     di, BYTE TRANSLATED_DPT_size * 2
    ret
%endif

GetBufferForDrive80hToESDI:
    push    ds
    pop     es
    mov     di, [cs:ROMVARS.bStealSize] ; No harm to read WORD
    eSHL_IM di, 10                      ; DI = RAMVARS size in bytes
%ifdef MODULE_EBIOS
    sub     di, BYTE (TRANSLATED_DPT_size * 2) + DPTE_size
%else
    sub     di, BYTE TRANSLATED_DPT_size * 2
%endif
    ret


;--------------------------------------------------------------------
; FillToESDIusingDPTfromDSSI
;   Parameters:
;       CL:     Device Control Byte
;       DS:SI:  Ptr to DPT
;       ES:DI   Ptr to destination buffer
;   Returns:
;       Nothing
;   Corrupts registers:
;       AX, CX, DX
;--------------------------------------------------------------------
FillToESDIusingDPTfromDSSI:
    mov     ax, [si+DPT.wLchsCylinders]
    call    AH8h_LimitAXtoMaximumLCylinders
    test    BYTE [si+DPT.bFlagsLow], MASKL_DPT_TRANSLATEMODE
    jz      SHORT FillStandardDPTtoESDIfromDPTinDSSI
    ; Fall to FillTranslatedDPTtoESDIfromDPTinDSSI

;--------------------------------------------------------------------
; FillTranslatedDPTtoESDIfromDPTinDSSI
;   Parameters:
;       AX:     Number of Logical Cylinders
;       CL:     Device Control Byte
;       DS:SI:  Ptr to DPT
;       ES:DI:  Ptr to destination buffer
;   Returns:
;       Nothing
;   Corrupts registers:
;       AX, CX, DX
;--------------------------------------------------------------------
FillTranslatedDPTtoESDIfromDPTinDSSI:
    cwd                                 ; Clear for checksum
    call    StoswThenAddALandAHtoDL     ; Bytes 0 and 1 (Logical number of cylinders)

    mov     al, [si+DPT.bLchsHeads]
    mov     ah, TRANSLATED_DPT_SIGNATURE
    call    StoswThenAddALandAHtoDL     ; Bytes 2 (Logical number of heads) and 3 (Axh signature to indicate Translated DPT)

    eMOVZX  ax, [si+DPT.bPchsSectorsPerTrack]
    call    StoswThenAddALandAHtoDL     ; Bytes 4 (Physical sectors per track) and 5 (Write Precompensation Cylinder low)

    mov     al, ah                      ; Zero AX
    stosw                               ; Bytes 6 (Write Precompensation Cylinder high) and 7

    xchg    cx, ax                      ; Device Control byte to AL, zero to CX
    mov     ah, [si+DPT.wPchsCylinders]
    call    StoswThenAddALandAHtoDL     ; Bytes 8 (Drive Control Byte) and 9 (Physical number of cylinders low)

    mov     al, [si+DPT.wPchsCylinders+1]
    mov     ah, [si+DPT.bPchsHeads]
    call    StoswThenAddALandAHtoDL     ; Bytes 10 (Physical number of cylinders high) and 11 (Physical number of heads)

    xchg    cx, ax                      ; Zero to AX
    stosw                               ; Bytes 12 and 13 (Landing Zone Cylinder)

    mov     al, [si+DPT.bLchsSectorsPerTrack]
%ifndef USE_186
    call    StoswALandChecksumFromDL    ; Bytes 14 (Logical sectors per track) and 15 (Checksum)
    jmp     SHORT FillStandardDPTtoESDIfromDPTinDSSI.RestoreOffsetsAndReturn
%else
    push    FillStandardDPTtoESDIfromDPTinDSSI.RestoreOffsetsAndReturn
    ; Fall to StoswALandChecksumFromDL
%endif


;--------------------------------------------------------------------
; StoswALandChecksumFromDL
;   Parameters:
;       AL:     Last byte to store before checksum byte
;       DL:     Sum of bytes so far
;       ES:DI:  Ptr to where to store AL and Checksum byte
;   Returns:
;       DL:     Sum of bytes so far
;       DI:     Incremented by 2
;   Corrupts registers:
;       AH
;--------------------------------------------------------------------
StoswALandChecksumFromDL:
    mov     ah, al
    add     ah, dl
    neg     ah
    stosw
    ret


;--------------------------------------------------------------------
; FillStandardDPTtoESDIfromDPTinDSSI
;   Parameters:
;       AX:     Number of Physical Cylinders == Number of Logical Cylinders
;       CL:     Device Control Byte
;       DS:SI:  Ptr to DPT
;       ES:DI:  Ptr to destination buffer
;   Returns:
;       Nothing
;   Corrupts registers:
;       AX
;--------------------------------------------------------------------
FillStandardDPTtoESDIfromDPTinDSSI:
    stosw               ; Bytes 0 and 1 (Physical number of cylinders)
    eMOVZX  ax, [si+DPT.bLchsHeads]
    stosw               ; Bytes 2 (Physical number of heads) and 3
%ifdef USE_UNDOC_INTEL
%ifdef USE_386
    xor     al, al      ; Zero AX and clear CF
%else
    salc                ; Zero AX (CF cleared by eMOVZX above)
%endif
%else
    mov     al, ah      ; Zero AX
%endif
    stosw               ; Bytes 4 and 5 (Write Precompensation Cylinder low)
    stosw               ; Bytes 6 (Write Precompensation Cylinder high) and 7
    mov     al, cl      ; Device control byte to AL
    stosw               ; Bytes 8 (Drive Control Byte) and 9
%ifdef USE_UNDOC_INTEL
    salc                ; Zero AX (CF cleared above)
%else
    mov     al, ah      ; Zero AX
%endif
    stosw               ; Bytes 10 and 11
    stosw               ; Bytes 12 and 13 (Landing Zone Cylinder)
    mov     al, [si+DPT.bLchsSectorsPerTrack]
    stosw               ; Bytes 14 (Physical sectors per track) and 15

.RestoreOffsetsAndReturn:
    sub     di, BYTE STANDARD_DPT_size
    ret


%ifdef MODULE_EBIOS
;--------------------------------------------------------------------
; CompatibleDPT_CreateDeviceParameterTableExtensionToESBXfromDPTinDSSI
;   Parameters:
;       DS:SI:  Ptr to DPT (in RAMVARS segment)
;   Returns:
;       ES:BX:  Ptr to Device Parameter Table Extension (DPTE)
;   Corrupts registers:
;       AX, CX, DL, DI
;--------------------------------------------------------------------
CompatibleDPT_CreateDeviceParameterTableExtensionToESBXfromDPTinDSSI:
    call    GetTemporaryBufferForDPTEtoESDI ; Valid until next AH=48h call

    ; Set 32-bit flag for 32-bit controllers
    mov     cx, FLG_LBA_TRANSLATION_ENABLED ; DPTE.wFlags
    cmp     BYTE [si+DPT_ATA.bDevice], DEVICE_32BIT_ATA
    eCMOVE  cl, FLG_LBA_TRANSLATION_ENABLED | FLG_32BIT_XFER_MODE

    xor     dl, dl                          ; Clear DL for checksum
    push    bp
    mov     bp, StoswThenAddALandAHtoDL

    ; DPTE.wBasePort
    mov     ax, [si+DPT.wBasePort]
    call    bp                              ; Bytes 0 and 1

    ; DPTE.wControlBlockPort
    eMOVZX  bx, [si+DPT.bIdevarsOffset]
    mov     ax, [cs:bx+IDEVARS.wControlBlockPort]
    call    bp                              ; Bytes 2 and 3

    ; DPTE.bDrvnhead and DPTE.bBiosVendor
    xchg    di, si
    call    AccessDPT_GetDriveSelectByteToAL
    xchg    si, di
    call    bp                              ; Bytes 4 and 5

    ; DPTE.bIRQ and DPTE.bBlockSize
    mov     al, [cs:bx+IDEVARS.bIRQ]        ; No way to define that we might not use IRQ
    mov     ah, [si+DPT_ATA.bBlockSize]     ; DPT_ATA.bBlockSize must never be zero!
    sahf                                    ; Only block size = 1 sets CF
    jc      SHORT .DoNotSetBlockModeFlag
    or      cl, FLG_BLOCK_MODE_ENABLED
.DoNotSetBlockModeFlag:
    call    bp                              ; Bytes 6 and 7

    ; DPTE.bDmaChannelAndType and DPTE.bPioMode
    xor     ax, ax
%ifndef MODULE_ADVANCED_ATA
    stosw                                   ; Bytes 8 and 9
%else
    or      ah, [si+DPT_ADVANCED_ATA.bPioMode]
    jz      SHORT .DoNotSetFastPioFlag
    cmp     WORD [si+DPT_ADVANCED_ATA.wControllerID], BYTE 1
    sbb     cl, -1  ; FLG_FAST_PIO_ENABLED (if .wControllerID > 0)
.DoNotSetFastPioFlag:
    call    bp                              ; Bytes 8 and 9
%endif

    ; Set CHS translation flags and store DPTE.wFlags
    mov     al, [si+DPT.bFlagsLow]
    and     al, MASKL_DPT_TRANSLATEMODE
    jz      SHORT .NoChsTranslationOrBitShiftTranslationSet
    or      cl, FLG_CHS_TRANSLATION_ENABLED
    test    al, FLGL_DPT_ASSISTED_LBA
    jz      SHORT .NoChsTranslationOrBitShiftTranslationSet
    or      ch, LBA_ASSISTED_TRANSLATION << (TRANSLATION_TYPE_FIELD_POSITION - 8)
.NoChsTranslationOrBitShiftTranslationSet:
    xchg    ax, cx
    call    bp                              ; Bytes 10 and 11
    pop     bp

    ; DPTE.wReserved (must be zero)
    xor     ax, ax
    stosw                                   ; Bytes 12 and 13

    ; DPTE.bRevision and DPTE.bChecksum
    mov     al, DPTE_REVISION
    lea     bx, [di+2-DPTE_size]            ; The +2 compensates for the last WORD yet to be stored
    jmp     StoswALandChecksumFromDL        ; Bytes 14 and 15
%endif ; MODULE_EBIOS


;--------------------------------------------------------------------
; StoswThenAddALandAHtoDL
;   Parameters:
;       AX:     WORD to store
;       DL:     Sum of bytes so far
;       ES:DI:  Ptr to where to store AX
;   Returns:
;       DL:     Sum of bytes so far
;       DI:     Incremented by 2
;   Corrupts registers:
;       Nothing
;--------------------------------------------------------------------
StoswThenAddALandAHtoDL:
    stosw
    add     dl, al
    add     dl, ah
    ret