source: xtideuniversalbios/trunk/XTIDE_Universal_BIOS_Configurator_v2/Src/EEPROM.asm @ 621

; Project name  :   XTIDE Univeral BIOS Configurator v2
; Description   :   Functions for managing EEPROM contents.

;
; 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 initialized data
SECTION .data

ALIGN WORD_ALIGN
g_rgwEepromTypeToSizeInWords:
    dw      (2<<10) / 2     ; EEPROM_TYPE.2816_2kiB
    dw      (8<<10) / 2
    dw      (8<<10) / 2     ; EEPROM_TYPE.2864_8kiB_MOD
    dw      (32<<10) / 2
    dw      (64<<10) / 2
    dw      (32<<10) / 2    ; EEPROM_TYPE.SST_39SF
                            ; Actual size of flash will be larger than 32K,
                            ; however most (all?) XUB devices map a 32K window.

g_rgwEepromPageToSizeInBytes:
    dw      1               ; EEPROM_PAGE.1_byte
    dw      2
    dw      4
    dw      8
    dw      16
    dw      32
    dw      64



; Section containing code
SECTION .text

;--------------------------------------------------------------------
; EEPROM_LoadXtideUniversalBiosFromRomToRamBufferAndReturnSizeInDXCX
;   Parameters:
;       Nothing
;   Returns:
;       DX:CX:  BIOS size in bytes
;   Corrupts registers:
;       BX, SI, DI
;--------------------------------------------------------------------
ALIGN JUMP_ALIGN
EEPROM_LoadXtideUniversalBiosFromRomToRamBufferAndReturnSizeInDXCX:
    push    es

    call    EEPROM_FindXtideUniversalBiosROMtoESDI
    call    EEPROM_GetXtideUniversalBiosSizeFromESDItoDXCX
    xor     si, si              ; Load from beginning of ROM
    call    LoadBytesFromRomToRamBuffer

    pop     es
    ret


;--------------------------------------------------------------------
; EEPROM_GetXtideUniversalBiosSizeFromESDItoDXCX
;   Parameters:
;       ES:DI:  Ptr to XTIDE Universal BIOS
;   Returns:
;       DX:CX:  Bios size in bytes
;   Corrupts registers:
;       Nothing
;--------------------------------------------------------------------
ALIGN JUMP_ALIGN
EEPROM_GetXtideUniversalBiosSizeFromESDItoDXCX:
    xor     dx, dx
    mov     ch, [es:di+ROMVARS.bRomSize]
    mov     cl, dl
    eSHL_IM ch, 1
    eRCL_IM dl, 1
    ret


;--------------------------------------------------------------------
; EEPROM_LoadOldSettingsFromRomToRamBuffer
;   Parameters:
;       Nothing
;   Returns:
;       CF:     Cleared if EEPROM was found
;               Set if EEPROM not found
;   Corrupts registers:
;       BX, CX, SI
;--------------------------------------------------------------------
ALIGN JUMP_ALIGN
EEPROM_LoadOldSettingsFromRomToRamBuffer:
    mov     cx, ROMVARS_size - ROMVARS.wFlags - 2   ; Number of bytes to load
    mov     si, ROMVARS.wFlags + 2                  ; Offset where to start loading
    ; Fall to LoadBytesFromRomToRamBuffer

;--------------------------------------------------------------------
; LoadBytesFromRomToRamBuffer
;   Parameters:
;       CX:     Number of bytes to load from ROM
;       SI:     Offset to first byte to load
;   Returns:
;       CF:     Cleared if EEPROM was found
;               Set if EEPROM not found
;   Corrupts registers:
;       BX, SI
;--------------------------------------------------------------------
ALIGN JUMP_ALIGN
LoadBytesFromRomToRamBuffer:
    push    es
    push    ds
    push    di

    call    EEPROM_FindXtideUniversalBiosROMtoESDI
    jc      SHORT .XtideUniversalBiosNotFound
    push    es
    pop     ds                                      ; DS:SI points to ROM

    call    Buffers_GetFileBufferToESDI
    mov     di, si                                  ; ES:DI points to RAM buffer

%ifdef CLD_NEEDED
    cld
%endif
    call    Memory_CopyCXbytesFromDSSItoESDI        ; Clears CF

.XtideUniversalBiosNotFound:
    pop     di
    pop     ds
    pop     es
    ret


;--------------------------------------------------------------------
; EEPROM_FindXtideUniversalBiosROMtoESDI
;   Parameters:
;       Nothing
;   Returns:
;       ES:DI:  EEPROM segment
;       CF:     Cleared if EEPROM was found
;               Set if EEPROM not found
;   Corrupts registers:
;       BX
;--------------------------------------------------------------------
ALIGN JUMP_ALIGN
EEPROM_FindXtideUniversalBiosROMtoESDI:
    push    si
    push    cx

    xor     di, di                  ; Zero DI (offset)
    mov     bx, 0C000h              ; First possible ROM segment
ALIGN JUMP_ALIGN
.SegmentLoop:
    mov     es, bx                  ; Possible ROM segment to ES
    call    Buffers_IsXtideUniversalBiosSignatureInESDI
    je      SHORT .RomFound         ; If equal, CF=0
    sub     bx, -80h                ; Increment by 2kB (minimum possible distance from the beginning of one option ROM to the next)
    jc      SHORT .SegmentLoop      ; Loop until segment overflows
    stc
.RomFound:
    pop     cx
    pop     si
    ret


;--------------------------------------------------------------------
; EEPROM_LoadFromRomToRamComparisonBuffer
;   Parameters:
;       Nothing
;   Returns:
;       Nothing
;   Corrupts registers:
;       BX, CX, SI, DI
;--------------------------------------------------------------------
ALIGN JUMP_ALIGN
EEPROM_LoadFromRomToRamComparisonBuffer:
    push    es
    push    ds

    eMOVZX  bx, [g_cfgVars+CFGVARS.bEepromType]
    mov     cx, [bx+g_rgwEepromTypeToSizeInWords]
    mov     ds, [g_cfgVars+CFGVARS.wEepromSegment]
    xor     si, si
    call    Buffers_GetFlashComparisonBufferToESDI
%ifdef CLD_NEEDED
    cld
%endif
    rep movsw

    pop     ds
    pop     es
    ret