source: xtideuniversalbios/trunk/XTIDE_Universal_BIOS/Src/Boot/BootMenuEvent.asm @ 88

; Project name  :   XTIDE Universal BIOS
; Description   :   Boot Menu event handler for menu library callbacks.

; Section containing code
SECTION .text

struc ITEM_TYPE_REFRESH
    .HardDisk           resb    2
    .FloppyDrive        resb    2
    .SpecialFunction    resb    2
endstruc


;--------------------------------------------------------------------
; BootMenuEvent_Handler
;   Common parameters for all events:
;       BX:         Menu event (anything from MENUEVENT struct)
;       SS:BP:      Menu library handle
;   Common return values for all events:
;       CF:         Set if event processed
;                   Cleared if event not processed
;   Corrupts registers:
;       All
;--------------------------------------------------------------------
ALIGN JUMP_ALIGN
BootMenuEvent_Handler:
    cmp     bx, MENUEVENT.RefreshItemFromCX ; Above last supported item?
    ja      SHORT .EventNotHandled
    jmp     [bx+.rgfnEventSpecificHandlers]
.EventNotHandled:
.IdleProcessing:
    clc
    ret

ALIGN WORD_ALIGN
.rgfnEventSpecificHandlers:
    dw      .InitializeMenuinitFromDSSI
    dw      .EventCompleted
    dw      .IdleProcessing
    dw      .ItemHighlightedFromCX
    dw      .ItemSelectedFromCX
    dw      .KeyStrokeInAX
    dw      BootMenuPrint_TitleStrings
    dw      .RefreshInformation
    dw      .RefreshItemFromCX


; Parameters:
;   DS:SI:      Ptr to MENUINIT struct to initialize
; Returns:
;   DS:SI:      Ptr to initialized MENUINIT struct
ALIGN JUMP_ALIGN
.InitializeMenuinitFromDSSI:
    push    ds
    call    RamVars_GetSegmentToDS
    call    .GetDefaultMenuitemToDX
    call    BootMenu_GetMenuitemCountToCX
    pop     ds
    mov     [si+MENUINIT.wItems], cx
    mov     [si+MENUINIT.wHighlightedItem], dx
    mov     WORD [si+MENUINIT.wTitleAndInfoLines], BOOT_MENU_TITLE_AND_INFO_LINES
    mov     BYTE [si+MENUINIT.bWidth], BOOT_MENU_WIDTH
    call    BootMenu_GetHeightToAHwithItemCountInCL
    mov     [si+MENUINIT.bHeight], ah
    stc
    ret

ALIGN JUMP_ALIGN
.GetDefaultMenuitemToDX:
    mov     dl, [cs:ROMVARS.bBootDrv]   ; Default boot drive
    call    BootMenu_IsDriveInSystem
    jnc     SHORT .DoNotSetDefaultMenuitem
    call    DriveXlate_SetDriveToSwap
    call    BootMenu_ConvertDriveToMenuitem
    mov     dx, cx
    ret
ALIGN JUMP_ALIGN
.DoNotSetDefaultMenuitem:
    xor     dx, dx                      ; Whatever appears first on boot menu
    ret


; Parameters:
;   CX:         Index of new highlighted item
;   DX:         Index of previously highlighted item or NO_ITEM_HIGHLIGHTED
ALIGN JUMP_ALIGN
.ItemHighlightedFromCX:
    push    cx
    push    dx
    call    RamVars_GetSegmentToDS
    call    DriveXlate_Reset
    call    BootMenu_ConvertMenuitemToDriveOrFunction
    jc      SHORT .UpdatePreviousAndNewMenuitem ; Selection changed to a function
    call    DriveXlate_SetDriveToSwap

.UpdatePreviousAndNewMenuitem:
    pop     ax      ; Update previous item
    CALL_MENU_LIBRARY RefreshItemFromAX
    pop     ax      ; Update new item
    CALL_MENU_LIBRARY RefreshItemFromAX
    CALL_MENU_LIBRARY RefreshInformation
    stc
    ret


; Parameters:
;   AL:         ASCII character for the key
;   AH:         Keyboard library scan code for the key
ALIGN JUMP_ALIGN
.KeyStrokeInAX:
    xor     ah, ah                  ; ASCII drive letter now in AX
    call    BootMenu_ConvertHotkeyToMenuitem
    cmp     cx, [bp+MENUINIT.wItems]
    jae     SHORT .EventNotHandled  ; Invalid key
    xchg    ax, cx
    CALL_MENU_LIBRARY HighlightItemFromAX
    ; Fall to .ItemSelectedFromCX


; Parameters:
;   CX:         Index of selected item
ALIGN JUMP_ALIGN
.ItemSelectedFromCX:
    CALL_MENU_LIBRARY Close
.EventCompleted:
    stc
    ret


; Parameters:
;   CX:         Index of item to refresh
;   Cursor has been positioned to the beginning of item line
ALIGN JUMP_ALIGN
.RefreshItemFromCX:
    mov     bx, .rgwItemTypeRefresh
    jmp     SHORT .RefreshItemOrInformationWithJumpTableInCSBX


; Parameters:
;   CX:         Index of highlighted item
;   Cursor has been positioned to the beginning of first line
ALIGN JUMP_ALIGN
.RefreshInformation:
    mov     bx, .rgwInformationItemTypeRefresh
    ; Fall to .RefreshItemOrInformationWithJumpTableInCSBX

;--------------------------------------------------------------------
; RefreshItemOrInformationWithJumpTableInCSBX
;   Parameters:
;       CX:     Index of selected menuitem
;       CS:BX:  Ptr to ITEM_TYPE_REFRESH jump table
;   Returns:
;       CF:     set since event processed
;--------------------------------------------------------------------
ALIGN JUMP_ALIGN
.RefreshItemOrInformationWithJumpTableInCSBX:
    cmp     cl, NO_ITEM_HIGHLIGHTED
    je      SHORT .EventCompleted

    call    RamVars_GetSegmentToDS
    call    BootMenu_ConvertMenuitemToDriveOrFunction
    jc      SHORT .DrawFunction
    test    dl, 80h                 ; Floppy drive?
    jz      SHORT .DrawFloppyDrive
    jmp     [cs:bx+ITEM_TYPE_REFRESH.HardDisk]
ALIGN JUMP_ALIGN
.DrawFunction:
    jmp     [cs:bx+ITEM_TYPE_REFRESH.SpecialFunction]
ALIGN JUMP_ALIGN
.DrawFloppyDrive:
    jmp     [cs:bx+ITEM_TYPE_REFRESH.FloppyDrive]

; Jump tables for .RefreshItemOrInformationWithJumpTableInCSBX
ALIGN WORD_ALIGN
.rgwItemTypeRefresh:
istruc ITEM_TYPE_REFRESH
    at  ITEM_TYPE_REFRESH.HardDisk,         dw  BootMenuPrint_HardDiskMenuitem
    at  ITEM_TYPE_REFRESH.FloppyDrive,      dw  BootMenuPrint_FloppyMenuitem
    at  ITEM_TYPE_REFRESH.SpecialFunction,  dw  BootMenuPrint_FunctionMenuitem
iend
.rgwInformationItemTypeRefresh:
istruc ITEM_TYPE_REFRESH
    at  ITEM_TYPE_REFRESH.HardDisk,         dw  BootMenuPrint_HardDiskMenuitemInformation
    at  ITEM_TYPE_REFRESH.FloppyDrive,      dw  BootMenuPrint_FloppyMenuitemInformation
    at  ITEM_TYPE_REFRESH.SpecialFunction,  dw  BootMenuPrint_ClearInformationArea
iend