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;* WinClose - "Closes" a window previously opened by the WinOpen procedure.
;* See also the WinOpen procedure.
;*
;* Shows:   DOS Function - 49h (Release Memory Block)
;*          Instructions - lodsw
;*          Operators - : (segment override)     SEG
;*
;* Uses:    vconfig - Video configuration structure (initialized
;*          by calling the GetVidConfig procedure)
;*
;* Params:  Adr - Segment address of buffer that holds screen contents
;*                 saved in WinOpen procedure
;*
;* Return:  None
 
WinClose PROC USES ds di si,
        Adr:WORD
 
        mov     ds, Adr                 ; DS:SI points to buffer
        sub     si, si
        lodsw
        mov     di, ax                  ; DI = video offset of window
        lodsw
        mov     bx, ax                  ; BX = number of window rows
        lodsw
        mov     cx, ax                  ; CX = number of columns
 
        mov     ax, SEG vconfig.sgmnt
        mov     es, ax                  ; Point ES to data segment
        push    es:vconfig.sgmnt
        pop     es                      ; ES = video segment
        mov     ax, 160                 ; Number of video cells/row
 
        .REPEAT
        push    di                      ; Save ptr to start of line
        push    cx                      ;   and number of columns
 
; Disable CGA video prior to memory move to avoid screen snow. (See the
; WinOpen and StrWrite procedures for further discussions on CGA snow.)
 
        .IF     vconfig.adapter == CGA  ; If CGA adapter,
        INVOKE  DisableCga              ;   disable video
        .ENDIF
 
        rep     movsw                   ; Copy one row to buffer
 
        .IF     vconfig.adapter == CGA  ; If CGA adapter,
        INVOKE  EnableCga               ;   reenable CGA video
        .ENDIF
        pop     cx                      ; Recover number of columns
        pop     di                      ;   and start of line
        add     di, ax                  ; Point to start of next line
        dec     bx                      ; Decrement row counter
        .UNTIL  zero?                   ;   until no rows remain
 
        mov     ah, 49h                 ; Request DOS Function 49h
        mov     es, Adr
        int     21h                     ; Release Memory Block
        ret
 
WinClose ENDP
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