source: xtideuniversalbios/trunk/Assembly_Library/Src/Menu/MenuLoop.asm@ 557

; Project name  :   Assembly Library
; Description   :   Menu loop for waiting keystrokes.

;
; 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

;--------------------------------------------------------------------
; MenuLoop_Enter
;   Parameters
;       SS:BP:  Ptr to MENU
;   Returns:
;       Nothing
;   Corrupts registers:
;       AX, BX, CX, DX, SI, DI
;--------------------------------------------------------------------
ALIGN MENU_JUMP_ALIGN
MenuLoop_Enter:
    call    KeystrokeProcessing
    call    TimeoutProcessing
%ifdef MENUEVENT_IDLEPROCESSING_ENABLE
    call    MenuEvent_IdleProcessing    ; User idle processing
%endif
    test    BYTE [bp+MENU.bFlags], FLG_MENU_EXIT
    jz      SHORT MenuLoop_Enter
    ret


;--------------------------------------------------------------------
; KeystrokeProcessing
; TimeoutProcessing
;   Parameters
;       SS:BP:  Ptr to MENU
;   Returns:
;       Nothing
;   Corrupts registers:
;       All, except SS:BP
;--------------------------------------------------------------------
ALIGN MENU_JUMP_ALIGN
KeystrokeProcessing:
    call    Keyboard_GetKeystrokeToAX
    jnz     SHORT ProcessKeystrokeFromAX
NoKeystrokeToProcess:
    ret

ALIGN MENU_JUMP_ALIGN
TimeoutProcessing:
    call    MenuTime_UpdateSelectionTimeout
    jnc     NoKeystrokeToProcess
    mov     al, CR  ; Fake ENTER to select item
    ; Fall to ProcessKeystrokeFromAX


;--------------------------------------------------------------------
; ProcessKeystrokeFromAX
;   Parameters
;       AL:     ASCII character
;       AH:     BIOS scan code
;       SS:BP:  Ptr to MENU
;   Returns:
;       Nothing
;   Corrupts registers:
;       AX, BX, CX, DX, SI, DI
;--------------------------------------------------------------------
ALIGN MENU_JUMP_ALIGN
ProcessKeystrokeFromAX:
    xchg    cx, ax
    call    MenuTime_StopSelectionTimeout
    xchg    ax, cx
    call    .ProcessMenuSystemKeystrokeFromAX
    jc      SHORT NoKeystrokeToProcess
    jmp     MenuEvent_KeyStrokeInAX

;--------------------------------------------------------------------
; .ProcessMenuSystemKeystrokeFromAX
;   Parameters
;       AL:     ASCII character
;       AH:     BIOS scan code
;       SS:BP:  Ptr to MENU
;   Returns:
;       CF:     Set if keystroke processed
;               Cleared if keystroke not processed
;       AL:     ASCII character (if CF cleared)
;       AH:     BIOS scan code (if CF cleared)
;   Corrupts registers:
;       BX, CX, DX, SI, DI
;--------------------------------------------------------------------
ALIGN MENU_JUMP_ALIGN
.ProcessMenuSystemKeystrokeFromAX:
%ifndef MENU_NO_ESC
    cmp     al, ESC
    je      SHORT .LeaveMenuWithoutSelectingItem
%endif
    cmp     al, CR
    je      SHORT .SelectItem

    test    BYTE [bp+MENU.bFlags], FLG_MENU_USER_HANDLES_SCROLLING
    jz      SHORT MenuLoop_ProcessScrollingKeysFromAX
    ret     ; Return with CF cleared since keystroke not processed

%ifndef MENU_NO_ESC
ALIGN MENU_JUMP_ALIGN
.LeaveMenuWithoutSelectingItem:
    call    MenuEvent_ExitMenu
    jnc     SHORT .CancelMenuExit
    call    MenuInit_CloseMenuWindow
    mov     WORD [bp+MENUINIT.wHighlightedItem], NO_ITEM_HIGHLIGHTED
.CancelMenuExit:
    stc
    ret
%endif

ALIGN MENU_JUMP_ALIGN
.SelectItem:
    mov     cx, [bp+MENUINIT.wHighlightedItem]
    call    MenuEvent_ItemSelectedFromCX
    stc
    ret


;--------------------------------------------------------------------
; MenuLoop_ProcessScrollingKeysFromAX
;   Parameters
;       AL:     ASCII character
;       AH:     BIOS scan code
;       SS:BP:  Ptr to MENU
;   Returns:
;       CF:     Set if keystroke processed
;               Cleared if keystroke not processed
;       AL:     ASCII character (if CF cleared)
;       AH:     BIOS scan code (if CF cleared)
;   Corrupts registers:
;       BX, CX, DX, SI, DI
;--------------------------------------------------------------------
ALIGN MENU_JUMP_ALIGN
MenuLoop_ProcessScrollingKeysFromAX:
    xchg    ah, al
    cmp     al, MENU_KEY_PGUP
    je      SHORT .ChangeToPreviousPage
    cmp     al, MENU_KEY_PGDN
    je      SHORT .ChangeToNextPage
    cmp     al, MENU_KEY_HOME
    je      SHORT .SelectFirstItem
    cmp     al, MENU_KEY_END
    je      SHORT .SelectLastItem

    cmp     al, MENU_KEY_UP
    je      SHORT .DecrementSelectedItem
    cmp     al, MENU_KEY_DOWN
    je      SHORT .IncrementSelectedItem
    clc     ; Clear CF since keystroke not processed
    xchg    ah, al
    ret

ALIGN MENU_JUMP_ALIGN
.ChangeToPreviousPage:
    call    MenuScrollbars_GetMaxVisibleItemsOnPageToCX
    xchg    ax, cx
    neg     ax
    mov     cx, [bp+MENUINIT.wHighlightedItem]
    add     cx, ax
    jge     SHORT .MoveHighlightedItemByAX  ; No rotation for PgUp
    ; Fall to .SelectFirstItem
ALIGN MENU_JUMP_ALIGN
.SelectFirstItem:
    mov     ax, [bp+MENUINIT.wHighlightedItem]
    neg     ax
    jmp     SHORT .MoveHighlightedItemByAX

ALIGN MENU_JUMP_ALIGN
.ChangeToNextPage:
    call    MenuScrollbars_GetMaxVisibleItemsOnPageToCX
    xchg    ax, cx
    mov     cx, [bp+MENUINIT.wHighlightedItem]
    add     cx, ax
    cmp     cx, [bp+MENUINIT.wItems]
    jb      SHORT .MoveHighlightedItemByAX  ; No rotation for PgDn
    ; Fall to .SelectLastItem
ALIGN MENU_JUMP_ALIGN
.SelectLastItem:
    stc
    mov     ax, [bp+MENUINIT.wItems]
    sbb     ax, [bp+MENUINIT.wHighlightedItem]
    jmp     SHORT .MoveHighlightedItemByAX

ALIGN MENU_JUMP_ALIGN
.DecrementSelectedItem:
    mov     ax, -1
    SKIP2B  cx  ; mov cx, <next instruction>
.IncrementSelectedItem:
    mov     al, 1   ; AH is already 0
ALIGN MENU_JUMP_ALIGN
.MoveHighlightedItemByAX:
    call    MenuScrollbars_MoveHighlightedItemByAX
    stc
    ret