source: xtideuniversalbios/trunk/XTIDE_Universal_BIOS_Configurator_v2/Src/Buffers.asm @ 109

; Project name  :   XTIDE Universal BIOS Configurator v2
; Description   :   Functions for accessing file and flash buffers.

; Section containing code
SECTION .text

;--------------------------------------------------------------------
; Buffers_Clear
;   Parameters:
;       Nothing
;   Returns:
;       Nothing
;   Corrupts registers:
;       AX, CX, DI, ES
;--------------------------------------------------------------------
ALIGN JUMP_ALIGN
Buffers_Clear:
    call    Buffers_GetFileBufferToESDI
    mov     cx, ROMVARS_size
    jmp     Memory_ZeroESDIwithSizeInCX


;--------------------------------------------------------------------
; Buffers_IsXtideUniversalBiosLoaded
;   Parameters:
;       Nothing
;   Returns:
;       ZF:     Set if supported version of XTIDE Universal BIOS is loaded
;               Cleared no file or some other file is loaded
;   Corrupts registers:
;       CX, SI, DI, ES
;--------------------------------------------------------------------
ALIGN JUMP_ALIGN
Buffers_IsXtideUniversalBiosLoaded:
    test    WORD [cs:g_cfgVars+CFGVARS.wFlags], FLG_CFGVARS_FILELOADED | FLG_CFGVARS_ROMLOADED
    jz      SHORT .NoFileOrBiosLoaded

    call    Buffers_GetFileBufferToESDI
    jmp     SHORT Buffers_IsXtideUniversalBiosSignatureInESDI
.NoFileOrBiosLoaded:
    or      cl, 1       ; Clear ZF
    ret


;--------------------------------------------------------------------
; Buffers_IsXtideUniversalBiosSignatureInESDI
;   Parameters:
;       ES:DI:  Ptr to possible XTIDE Universal BIOS location
;   Returns:
;       ZF:     Set if supported version of XTIDE Universal BIOS is loaded
;               Cleared no file or some other file is loaded
;   Corrupts registers:
;       CX, SI
;--------------------------------------------------------------------
ALIGN JUMP_ALIGN
Buffers_IsXtideUniversalBiosSignatureInESDI:
    push    di

    mov     si, g_szXtideUniversalBiosSignature
    add     di, BYTE ROMVARS.rgbSign
    mov     cx, XTIDE_SIGNATURE_LENGTH / 2
    cld
    eSEG_STR repe, cs, cmpsw

    pop     di
    ret


;--------------------------------------------------------------------
; Buffers_NewBiosWithSizeInCXandSourceInAXhasBeenLoadedForConfiguration
;   Parameters:
;       AX:     EEPROM source (FLG_CFGVARS_FILELOADED or FLG_CFGVARS_ROMLOADED)
;       DX:CX:  EEPROM size in bytes
;   Returns:
;       Nothing
;   Corrupts registers:
;       AX, CX, DX
;--------------------------------------------------------------------
ALIGN JUMP_ALIGN
Buffers_NewBiosWithSizeInDXCXandSourceInAXhasBeenLoadedForConfiguration:
    and     WORD [cs:g_cfgVars+CFGVARS.wFlags], ~(FLG_CFGVARS_FILELOADED | FLG_CFGVARS_ROMLOADED | FLG_CFGVARS_UNSAVED)
    or      WORD [cs:g_cfgVars+CFGVARS.wFlags], ax
    shr     dx, 1
    rcr     cx, 1
    mov     [cs:g_cfgVars+CFGVARS.wImageSizeInWords], cx
    ret


;--------------------------------------------------------------------
; Buffers_SetUnsavedChanges
; Buffers_ClearUnsavedChanges
;   Parameters:
;       SS:BP:  Menu handle
;   Returns:
;       Nothing
;   Corrupts registers:
;       Nothing
;--------------------------------------------------------------------
ALIGN JUMP_ALIGN
Buffers_SetUnsavedChanges:
    or      WORD [g_cfgVars+CFGVARS.wFlags], FLG_CFGVARS_UNSAVED
    ret

ALIGN JUMP_ALIGN
Buffers_ClearUnsavedChanges:
    and     WORD [g_cfgVars+CFGVARS.wFlags], ~FLG_CFGVARS_UNSAVED
    ret


;--------------------------------------------------------------------
; Buffers_SaveChangesIfFileLoaded
;   Parameters:
;       Nothing
;   Returns:
;       Nothing
;   Corrupts registers:
;       AX, BX, CX, SI, DI
;--------------------------------------------------------------------
ALIGN JUMP_ALIGN
Buffers_SaveChangesIfFileLoaded:
    mov     ax, [cs:g_cfgVars+CFGVARS.wFlags]
    and     ax, BYTE (FLG_CFGVARS_FILELOADED | FLG_CFGVARS_UNSAVED)
    cmp     ax, BYTE (FLG_CFGVARS_FILELOADED | FLG_CFGVARS_UNSAVED)
    jne     SHORT .NothingToSave
    call    Dialogs_DisplaySaveChangesDialog
    jnz     SHORT .NothingToSave
    jmp     BiosFile_SaveUnsavedChanges
ALIGN JUMP_ALIGN
.NothingToSave:
    ret


;--------------------------------------------------------------------
; Buffers_AppendZeroesIfNeeded
;   Parameters:
;       Nothing
;   Returns:
;       Nothing
;   Corrupts registers:
;       AX, CX, DI
;--------------------------------------------------------------------
ALIGN JUMP_ALIGN
Buffers_AppendZeroesIfNeeded:
    push    es

    eMOVZX  di, BYTE [cs:g_cfgVars+CFGVARS.bEepromType]
    mov     cx, [cs:di+g_rgwEepromTypeToSizeInWords]
    sub     cx, [cs:g_cfgVars+CFGVARS.wImageSizeInWords]    ; CX = WORDs to append
    jle     SHORT .NoNeedToAppendZeroes

    call    Buffers_GetFileBufferToESDI
    mov     ax, [cs:g_cfgVars+CFGVARS.wImageSizeInWords]
    shl     ax, 1
    add     di, ax          ; ES:DI now point first unused image byte
    xor     ax, ax
    cld
    rep stosw
ALIGN JUMP_ALIGN
.NoNeedToAppendZeroes:
    pop     es
    ret


;--------------------------------------------------------------------
; Buffers_GenerateChecksum
;   Parameters:
;       Nothing
;   Returns:
;       Nothing
;   Corrupts registers:
;       AX, BX, CX, DI
;--------------------------------------------------------------------
ALIGN JUMP_ALIGN
Buffers_GenerateChecksum:
    push    es

    call    Buffers_GetFileBufferToESDI
    mov     cx, [cs:g_cfgVars+CFGVARS.wImageSizeInWords]
    shl     cx, 1           ; Words to bytes
    dec     cx              ; Leave space for checksum byte
    xor     ax, ax
ALIGN JUMP_ALIGN
.SumNextByte:
    add     al, [es:di]
    inc     di
    loop    .SumNextByte
    neg     al
    mov     [es:di], al

    pop     es
    ret


;--------------------------------------------------------------------
; Buffers_GetRomvarsFlagsToAX
;   Parameters:
;       Nothing
;   Returns:
;       AX:     ROMVARS.wFlags
;   Corrupts registers:
;       BX
;--------------------------------------------------------------------
ALIGN JUMP_ALIGN
Buffers_GetRomvarsFlagsToAX:
    mov     bx, ROMVARS.wFlags
    ; Fall to Buffers_GetRomvarsValueToAXfromOffsetInBX

;--------------------------------------------------------------------
; Buffers_GetRomvarsValueToAXfromOffsetInBX
;   Parameters:
;       BX:     ROMVARS offset
;   Returns:
;       AX:     Value
;   Corrupts registers:
;       Nothing
;--------------------------------------------------------------------
ALIGN JUMP_ALIGN
Buffers_GetRomvarsValueToAXfromOffsetInBX:
    push    es
    push    di
    call    Buffers_GetFileBufferToESDI
    mov     ax, [es:bx+di]
    pop     di
    pop     es
    ret


;--------------------------------------------------------------------
; Buffers_GetFileBufferToESDI
; Buffers_GetFlashComparisonBufferToESDI
; Buffers_GetFileDialogItemBufferToESDI
;   Parameters:
;       Nothing
;   Returns:
;       ES:DI:  Ptr to file buffer
;   Corrupts registers:
;       Nothing
;--------------------------------------------------------------------
ALIGN JUMP_ALIGN
Buffers_GetFlashComparisonBufferToESDI:
Buffers_GetFileDialogItemBufferToESDI:
    call    Buffers_GetFileBufferToESDI
    push    di
    mov     di, es
    add     di, 1000h       ; Third 64k page
    mov     es, di
    pop     di
    ret
ALIGN JUMP_ALIGN
Buffers_GetFileBufferToESDI:
    mov     di, cs
    add     di, 1000h       ; Change to next 64k page
    mov     es, di
    xor     di, di          ; Ptr now in ES:DI
    ret