JPS63304291A - Bit map display management system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a management method for a bitmap display having a window buffer for storing each window image for the purpose of multi-window display.

(Prior art) Conventionally, this type of management system includes, for example, Nikkei Electronics, Nikkei McGraw-Hill, July 29, 1985.
As disclosed in Japanese, P., 141-161, there were two main types:

(1) A method in which a window buffer is secured on the main memory, and the host processor reads data from the window buffer to change the display screen and sends it to the screen control unit. In other words, in this method, the window area is managed only within the window buffer on the main storage device.

(2) A frame buffer and a window buffer are secured in the memory within the bitmap display, and the host processor sends a request to the screen control unit to change the display screen, and the frame buffer and window buffer are changed there. method. In other words, in this method, the window area is managed only by the window buffer in the memory within the bitmap display.

(Problems to be Solved by the Invention) However, the method (1) above has problems in that the load on the host processor is heavy and it takes a long time to rewrite the screen. Further, although the above method (2) reduces the load on the host processor, there is a problem in that the number of window areas that can be created is limited by the capacity of the window buffer.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for managing a bitmap display suitable for multi-window display by eliminating the above-described problems of the load on the host processor and the limited number of window areas.

(Means for Solving the Problems) This invention aims at multi-window display, and is connected to a main storage device and a host processor by a system bus, and has a window buffer for storing each window image. In order to solve the problems of the prior art described above, a first means for detecting the oldest referenced window image in a window buffer; a second means for transferring an old window image to the main storage device based on the detection result of the detection device when the window buffer becomes full; and a second means for transferring an old window image to the main storage device when the window buffer becomes full; The third step transfers the window image to the window buffer again when
This means that the

(Operation) In the present invention, when the number of windows to be displayed increases and a new window area cannot be secured in the window buffer, the first means checks the oldest referenced existing window image.

The second means receives the information from the first means, requests the host processor to secure an area on the main memory, transfers the window image to the main memory, and secures the window area on the window buffer. Work like you do.

The third means is to secure an area on the window buffer and transfer the window image transferred to the main storage device to the window buffer again when a command such as rectangular transfer between window areas is issued from the host processor. Nii〈. Therefore, the load on the host processor is reduced, and at the same time, the window area that can be created is no longer limited by the capacity of the window buffer, thus solving the problems of the prior art.

(Embodiment) FIG. 1 is a block diagram showing an embodiment of the present invention, in which 1 is a bitmap display device, 2 is an image controller, 3 is a frame buffer, 4 is a window buffer, 5 is a CRT,
6 is a host processor, 7 is a main storage device, and 8 is a system bus.

The window buffer 4 is a bitmap display memory that holds the window image to be displayed, and is connected to the image controller 2 as well as the system bus 8, and can also be directly referenced from the host processor 6. It is possible.

The image controller 2 executes the following instructions from the host processor 6.

(1) Securing a window area of a specified size in the window buffer 4 (2) Transferring a rectangular area between window areas (3) Writing a graphic element into the window area (4) Writing a window area to a specified position in the frame buffer 3 The transfer image controller 2 functions as a window area management block.
It has a reference time field on the main storage device 7, and the current time is written into the field each time the window area is referenced by the above command. FIG. 2 shows the configuration of the management block, which includes, in addition to the reference time field, fields for the number of horizontal dots and number of vertical dots necessary for securing a window area, and an address field on the main storage device 7.

The host processor 6 issues the above command to the image controller 2 according to a program stored in the main storage device 7, thereby displaying a plurality of windows in a superimposed manner on the CRTS.

When the number of windows to be displayed increases and it becomes impossible to allocate a new window area in the window buffer 4, the image controller 2 searches the reference time field of each existing window area and selects the oldest referenced window. The program extracts the area, requests the host processor 6 to secure an area on the main memory device 7 sufficient to save the window area contents from the horizontal dot and vertical dot number fields, and saves the window area contents on the main memory device 7. transfer to the area of Next, release the window area on window buffer 4,
The fact that the window image is on the main memory 7 and the address on the main memory 7 are recorded in the window area management block on the main memory 7. After securing a sufficient area on the window buffer 4 by evacuating the oldest window area to the main memory 7 in this way,
Allocate window area.

A command such as rectangular transfer between window areas is issued from the host processor 6, and the window area is transferred to the main memory 7.
In the case where the image controller 2 reserves an area on the window buffer 4, transfers the image from the main storage device 7 to the window area, and sends the image to the main storage device 7 to the host processor 6. After requesting the release of the area, execute the specified command. At this time, if a sufficient area cannot be secured on the window buffer 4, the old window area is saved to the main storage device 7 in the same manner as described above for securing the window area.

(Effects of the Invention) As described in detail above, according to the present invention, when the window buffer of a bitmap display device becomes full of window areas and a new window area cannot be created on the window buffer, the old Since the window images are saved on the main memory, the number and size of windows that can be created is not limited by the capacity of the window buffer, and can be increased according to the available main memory area. Further, since window images that have been recently referenced, that is, are likely to be referenced in the future, are placed on the window buffer, which can be operated at high speed, efficiency in window operations is less degraded.

Furthermore, in a computer that uses virtual memory control, by saving window images in virtual space, it is possible to create a virtually unlimited number of windows.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a window area management block diagram. 1.--Bitmap display device 2.--Image controller 3.--Frame buffer 4.--Window buffer--CRT 6.--Host processor 7.--Main storage device 8--System bus

Claims (1)

[Scope of Claim] A bitmap display device connected to a main storage device and a host processor by a system bus, intended for multi-window display, and having a window buffer for storing each window image, comprising: each window in the window buffer; a first means for detecting the oldest referenced image among the images; a second means for transferring the oldest window image to the main storage device based on the detection result of the detection means when the window buffer is full; 1. A bitmap display management system comprising: a third means for transferring a window image transferred to a storage device again to a window buffer when a command is issued from a host processor for the window image transferred to the storage device.