source: xtideuniversalbios/trunk/Assembly_Library/Src/Display/DisplayCursor.asm @ 396

; Project name  :   Assembly Library
; Description   :   Functions for managing display cursor.

;
; XTIDE Universal BIOS and Associated Tools 
; Copyright (C) 2009-2010 by Tomi Tilli, 2011-2012 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

;--------------------------------------------------------------------
; DisplayCursor_SetShapeFromAX
;   Parameters:
;       AX:     Cursor shape (AH=Start scan line, AL=End scan line)
;       DS:     BDA segment (zero)
;   Returns:
;       Nothing
;   Corrupts registers:
;       Nothing
;--------------------------------------------------------------------
ALIGN DISPLAY_JUMP_ALIGN
DisplayCursor_SetShapeFromAX:
    mov     [VIDEO_BDA.displayContext+DISPLAY_CONTEXT.wCursorShape], ax
    ret


;--------------------------------------------------------------------
; DisplayCursor_SetCoordinatesFromAX
;   Parameters:
;       AL:     Cursor column (X-coordinate)
;       AH:     Cursor row (Y-coordinate)
;       DS:     BDA segment (zero)
;   Returns:
;       DI:     Offset to cursor location in video RAM
;   Corrupts registers:
;       AX, DX
;--------------------------------------------------------------------
ALIGN DISPLAY_JUMP_ALIGN
DisplayCursor_SetCoordinatesFromAX:
    xchg    dx, ax
    mov     ax, [VIDEO_BDA.wColumns]        ; Column count, 40 or 80
    mul     dh                              ; AX = Column count * row index
    xor     dh, dh
    add     ax, dx                          ; Add column offset
    shl     ax, 1                           ; Convert to WORD offset
    add     ax, [VIDEO_BDA.wPageOffset]     ; AX = Video RAM offset
    mov     [VIDEO_BDA.displayContext+DISPLAY_CONTEXT.fpCursorPosition], ax
    xchg    di, ax
    ret


;--------------------------------------------------------------------
; DisplayCursor_GetSoftwareCoordinatesToAX
;   Parameters:
;       AX:     Offset to cursor location in selected page
;       DS:     BDA segment (zero)
;   Returns:
;       AL:     Cursor column (X-coordinate)
;       AH:     Cursor row (Y-coordinate)
;   Corrupts registers:
;       Nothing
;--------------------------------------------------------------------
ALIGN DISPLAY_JUMP_ALIGN
DisplayCursor_GetSoftwareCoordinatesToAX:
    mov     ax, [VIDEO_BDA.displayContext+DISPLAY_CONTEXT.fpCursorPosition]
    sub     ax, [VIDEO_BDA.wPageOffset]
    shr     ax, 1                           ; WORD offset to character offset
    div     BYTE [VIDEO_BDA.wColumns]       ; AL = full rows, AH = column index for last row
    xchg    al, ah
    ret


;--------------------------------------------------------------------
; DisplayCursor_GetHardwareCoordinatesToAX
;   Parameters:
;       DS:     BDA segment (zero)
;   Returns:
;       AL:     Hardware cursor column (X-coordinate)
;       AH:     Hardware cursor row (Y-coordinate)
;   Corrupts registers:
;       DX
;--------------------------------------------------------------------
ALIGN DISPLAY_JUMP_ALIGN
DisplayCursor_GetHardwareCoordinatesToAX:
    push    cx
    push    bx

    mov     ah, GET_CURSOR_POSITION_AND_SIZE
    mov     bh, [VIDEO_BDA.bActivePage]
    int     BIOS_VIDEO_INTERRUPT_10h
    xchg    ax, dx

    pop     bx
    pop     cx
    ret


;--------------------------------------------------------------------
; DisplayCursor_SynchronizeShapeToHardware
;   Parameters:
;       DS:     BDA segment (zero)
;   Returns:
;       Nothing
;   Corrupts registers:
;       AX, DX
;--------------------------------------------------------------------
ALIGN DISPLAY_JUMP_ALIGN
DisplayCursor_SynchronizeShapeToHardware:
    mov     dx, [VIDEO_BDA.displayContext+DISPLAY_CONTEXT.wCursorShape]
    ; Fall to .SetHardwareCursorShapeFromDX

;--------------------------------------------------------------------
; .SetHardwareCursorShapeFromDX
;   Parameters:
;       DX:     Cursor shape
;       DS:     BDA segment (zero)
;   Returns:
;       Nothing
;   Corrupts registers:
;       AX
;--------------------------------------------------------------------
.SetHardwareCursorShapeFromDX:
    cmp     dx, [VIDEO_BDA.wCursorShape]
    je      SHORT .Return                   ; Return if no changes
    push    cx
    mov     cx, dx                          ; BIOS wants cursor shape in CX
    mov     al, [VIDEO_BDA.bMode]           ; Load video mode to prevent lock ups on some BIOSes
    mov     ah, SET_TEXT_MODE_CURSOR_SHAPE
    int     BIOS_VIDEO_INTERRUPT_10h
    pop     cx
.Return:
    ret


;--------------------------------------------------------------------
; DisplayCursor_SynchronizeCoordinatesToHardware
;   Parameters:
;       DS:     BDA segment (zero)
;   Returns:
;       Nothing
;   Corrupts registers:
;       AX, DX
;--------------------------------------------------------------------
ALIGN DISPLAY_JUMP_ALIGN
DisplayCursor_SynchronizeCoordinatesToHardware:
    call    DisplayCursor_GetSoftwareCoordinatesToAX
    ; Fall to .SetHardwareCursorCoordinatesFromAX

;--------------------------------------------------------------------
; .SetHardwareCursorCoordinatesFromAX
;   Parameters:
;       AL:     Cursor column (X-coordinate)
;       AH:     Cursor row (Y-coordinate)
;       DS:     BDA segment (zero)
;   Returns:
;       Nothing
;   Corrupts registers:
;       AX, DX
;--------------------------------------------------------------------
.SetHardwareCursorCoordinatesFromAX:
    push    bx
    xchg    dx, ax                          ; BIOS wants coordinates in DX
    mov     ah, SET_CURSOR_POSITION
    mov     bh, [VIDEO_BDA.bActivePage]
    int     BIOS_VIDEO_INTERRUPT_10h
    pop     bx
    ret