source: xtideuniversalbios/trunk/XTIDE_Universal_BIOS/Src/Device/IDE/IdeIO.asm

; Project name  :   XTIDE Universal BIOS
; Description   :   IDE Register I/O functions when supporting 8-bit
;                   devices that need address translations.

;
; 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

;--------------------------------------------------------------------
; IdeIO_InputStatusRegisterToAL
;   Parameters:
;       DS:DI:  Ptr to DPT (in RAMVARS segment)
;   Returns:
;       AL:     IDE Status Register contents
;   Corrupts registers:
;       BX, DX
;--------------------------------------------------------------------
ALIGN JUMP_ALIGN
IdeIO_InputStatusRegisterToAL:
%ifndef MODULE_8BIT_IDE
    INPUT_TO_AL_FROM_IDE_REGISTER STATUS_REGISTER_in
    ret

%else
    mov     dl, STATUS_REGISTER_in
    ; Fall to IdeIO_InputToALfromIdeRegisterInDL

;--------------------------------------------------------------------
; IdeIO_InputToALfromIdeRegisterInDL
;   Parameters:
;       DL:     IDE Register
;       DS:DI:  Ptr to DPT (in RAMVARS segment)
;   Returns:
;       AL:     Inputted byte
;   Corrupts registers:
;       BX, DX
;--------------------------------------------------------------------
IdeIO_InputToALfromIdeRegisterInDL:
    xor     dh, dh  ; IDE Register index now in DX...
    mov     al, [di+DPT_ATA.bDevice]
    cmp     al, DEVICE_8BIT_XTIDE_REV2
    jb      SHORT .InputToALfromRegisterInDX    ; Standard IDE controllers and XTIDE rev 1
    mov     bx, dx  ; ...and BX for A0<->A3 swap and for memory mapped I/O

%ifdef MODULE_8BIT_IDE_ADVANCED
    cmp     al, DEVICE_8BIT_XTIDE_REV2_OLIVETTI
    jbe     SHORT .ReverseA0andA3fromRegisterIndexInDX

    eSHL_IM dx, 1   ; ADP50L and XT-CF
    cmp     al, DEVICE_8BIT_JRIDE_ISA
    jb      SHORT .InputToALfromRegisterInDX    ; All XT-CF modes
    mov     bh, JRIDE_COMMAND_BLOCK_REGISTER_WINDOW_OFFSET >> 8
    je      SHORT .InputToALfromMemoryMappedRegisterInBX
    mov     bl, dl
    mov     bh, ADP50L_COMMAND_BLOCK_REGISTER_WINDOW_OFFSET >> 8

.InputToALfromMemoryMappedRegisterInBX:
    push    ds
    mov     ds, [di+DPT.wBasePort]  ; Segment for JR-IDE/ISA and ADP50L
    mov     al, [bx]
    pop     ds
    ret
%endif

.ReverseA0andA3fromRegisterIndexInDX:
    mov     dl, [cs:bx+g_rgbSwapA0andA3fromIdeRegisterIndex]

.InputToALfromRegisterInDX:
    add     dx, [di+DPT.wBasePort]
    in      al, dx
    ret


;--------------------------------------------------------------------
; IdeIO_OutputALtoIdeControlBlockRegisterInDL
;   Parameters:
;       AL:     Byte to output
;       DL:     IDE Control Block Register
;       DS:DI:  Ptr to DPT (in RAMVARS segment)
;   Returns:
;       Nothing
;   Corrupts registers:
;       BX, DX
;--------------------------------------------------------------------
IdeIO_OutputALtoIdeControlBlockRegisterInDL:
    xor     dh, dh  ; IDE Register index now in DX
    mov     bl, [di+DPT_ATA.bDevice]
    cmp     bl, DEVICE_8BIT_XTIDE_REV2
    jb      SHORT .OutputALtoControlBlockRegisterInDX   ; Standard IDE controllers and XTIDE rev 1

%ifdef MODULE_8BIT_IDE_ADVANCED
    cmp     bl, DEVICE_8BIT_XTIDE_REV2_OLIVETTI
    jbe     SHORT .ReverseA0andA3fromRegisterIndexInDX

    ; At this point remaining controllers (JRIDE, XTCF and ADP50L) all have a control
    ; block offset of 8 or (8<<1) so we add 8 here and do the SHL 1 later if needed.
    add     dx, BYTE 8
    cmp     bl, DEVICE_8BIT_JRIDE_ISA
    jb      SHORT IdeIO_OutputALtoIdeRegisterInDL.ShlRegisterIndexInDXandOutputAL   ; All XT-CF modes
    mov     bx, JRIDE_CONTROL_BLOCK_REGISTER_WINDOW_OFFSET - 8          ; Zeroes BL. -8 compensates for the ADD
    je      SHORT IdeIO_OutputALtoIdeRegisterInDL.OutputALtoMemoryMappedRegisterInDXwithWindowOffsetInBX
    ; The commented instructions below shows what happens next (saved for clarity) but as an optimization
    ; we can accomplish the same thing with this jump.
    jmp     SHORT IdeIO_OutputALtoIdeRegisterInDL.ShlDXandMovHighByteOfADP50LoffsetsToBH
;   eSHL_IM dx, 1
;   mov     bh, (ADP50L_CONTROL_BLOCK_REGISTER_WINDOW_OFFSET - 16) >> 8 ; -16 compensates for the ADD and SHL
;   jmp     SHORT IdeIO_OutputALtoIdeRegisterInDL.OutputALtoMemoryMappedRegisterInDXwithWindowOffsetInBX
%endif

.ReverseA0andA3fromRegisterIndexInDX:
    ; We cannot use lookup table since A3 will be always set because
    ; Control Block Registers start from Command Block + 8h. We can do
    ; a small trick since we only access Device Control Register at
    ; offset 6h: Always clear A3 and set A0.
    call    AccessDPT_GetIdevarsToCSBX
    add     dx, [cs:bx+IDEVARS.wControlBlockPort]
    xor     dl, 1001b                       ; Clear A3, Set A0
    out     dx, al
    ret

.OutputALtoControlBlockRegisterInDX:
    call    AccessDPT_GetIdevarsToCSBX
    add     dx, [cs:bx+IDEVARS.wControlBlockPort]
    out     dx, al
    ret


;--------------------------------------------------------------------
; IdeIO_OutputALtoIdeRegisterInDL
;   Parameters:
;       AL:     Byte to output
;       DL:     IDE Command Block Register
;       DS:DI:  Ptr to DPT (in RAMVARS segment)
;   Returns:
;       Nothing
;   Corrupts registers:
;       BX, DX
;--------------------------------------------------------------------
ALIGN JUMP_ALIGN
IdeIO_OutputALtoIdeRegisterInDL:
    xor     dh, dh  ; IDE Register index now in DX
    mov     bl, [di+DPT_ATA.bDevice]
    cmp     bl, DEVICE_8BIT_XTIDE_REV2
    jb      SHORT OutputALtoRegisterInDX    ; Standard IDE controllers and XTIDE rev 1

%ifdef MODULE_8BIT_IDE_ADVANCED
    cmp     bl, DEVICE_8BIT_XTIDE_REV2_OLIVETTI
    jbe     SHORT .ReverseA0andA3fromRegisterIndexInDX

    cmp     bl, DEVICE_8BIT_JRIDE_ISA
    jb      SHORT .ShlRegisterIndexInDXandOutputAL  ; All XT-CF modes
    mov     bx, JRIDE_COMMAND_BLOCK_REGISTER_WINDOW_OFFSET  ; Zeroes BL
    je      SHORT .OutputALtoMemoryMappedRegisterInDXwithWindowOffsetInBX
.ShlDXandMovHighByteOfADP50LoffsetsToBH:
    eSHL_IM dx, 1
    mov     bh, ADP50L_COMMAND_BLOCK_REGISTER_WINDOW_OFFSET >> 8    ; BL is zero so we only need to change BH

.OutputALtoMemoryMappedRegisterInDXwithWindowOffsetInBX:
    add     bx, dx
    push    ds
    mov     ds, [di+DPT.wBasePort]  ; Segment for JR-IDE/ISA and ADP50L
    mov     [bx], al
    pop     ds
    ret
%endif

.ReverseA0andA3fromRegisterIndexInDX:
    mov     bx, dx
    mov     dl, [cs:bx+g_rgbSwapA0andA3fromIdeRegisterIndex]
    SKIP2B  bx  ; Skip eSHL_IM dx, 1

.ShlRegisterIndexInDXandOutputAL:
    eSHL_IM dx, 1
    ; Fall to OutputALtoRegisterInDX

ALIGN JUMP_ALIGN
OutputALtoRegisterInDX:
    add     dx, [di+DPT.wBasePort]
    out     dx, al
    ret



; A0 <-> A3 lookup table
g_rgbSwapA0andA3fromIdeRegisterIndex:
    db  0000b   ; <-> 0000b, 0
    db  1000b   ; <-> 0001b, 1
    db  0010b   ; <-> 0010b, 2
    db  1010b   ; <-> 0011b, 3
    db  0100b   ; <-> 0100b, 4
    db  1100b   ; <-> 0101b, 5
    db  0110b   ; <-> 0110b, 6
    db  1110b   ; <-> 0111b, 7

%endif ; MODULE_8BIT_IDE