JPH077254B2 - Bitmap display management method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a bitmap display management system having a window buffer for storing each window image intended for multi-window display.

(Prior Art) Conventionally, as a management system of this type, for example, Nikkei Electronics, Nikkei McGraw-Hill, July 29, 1985, p.141.
As disclosed in No. 161, there are the following two main types.

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

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

(Problems to be Solved by the Invention) However, the above method (1) has a problem that the load of the host processor is heavy and the time required for screen rewriting is long. Further, in the above method (2), the load on the host processor is reduced, but the number of window regions that can be created is limited by the capacity of the window buffer.

It is an object of the present invention to eliminate the above-mentioned problems of the load on the host processor and the limitation of the number of window areas, and to provide a method for managing a bitmap display suitable for multi-window display.

(Means for Solving Problems) The present invention is intended for multi-window display, is connected to a main storage device and a host processor by a system bus, and is intended for multi-window display, and is a window buffer for storing each window image. And a first means for detecting the oldest referenced one of the window images in the window buffer in order to solve the above-mentioned problems of the prior art. When the window buffer is full, a second means for transferring an old window image to the main memory based on the detection result of the detecting means, and an instruction issued from the host processor to the window image transferred to the main memory. The window image again when It is provided with a third means for transferring to.

(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 window image among existing window images. The second means receives the information from the first means, requests the host processor to secure an area on the main storage device, transfers the window image to the main storage device, and secures the window area on the window buffer. Work to do. The third means secures an area on the window buffer and transfers the window image transferred to the main memory again to the window buffer when the host processor issues an instruction such as a rectangular transfer between window areas. To work. Therefore, the load on the host processor is reduced, and at the same time, the window area that can be created is not limited by the capacity of the window buffer, and the problems of the prior art are solved.

(Embodiment) FIG. 1 is a configuration diagram showing an embodiment of the present invention, 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 memory, and 8 is a system bus.

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

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 graphic elements in the window area (4) Window area at a specified position of the frame buffer 3 The image controller 2 as a management block of the window area,
The main memory 7 has a reference time field, and the current time is written in the field each time the window area is referenced by the above instruction. FIG. 2 shows the configuration of the management block, which has, in addition to the reference time field, a horizontal dot number field, a vertical dot number field, and an address field on the main memory 7 necessary for securing the window area.

The host processor 6 issues a command to the image controller 2 according to a program stored in the main memory 7 to display a plurality of windows on the CRT 5 in a superposed manner.

When the number of windows to be displayed increases and it becomes impossible to secure a new window area in the window buffer 4, the image controller 2 searches the reference time field of each existing window area, and the oldest referenced window is displayed. The host processor 6 is requested to secure an area on the main memory 7 sufficient to extract the area and save the window area content from the horizontal dot and vertical dot number fields, and the window area content on the main memory 7 is stored. Transfer to the area. Next, the window area on the window buffer 4 is released,
In the window area management block on the main memory 7, the fact that the window image is on the main memory 7 and the address on the main memory 7 are recorded. In this way, the old window area is sequentially saved in the main storage device 7 to secure a sufficient area in the window buffer 4 and then secure the 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 storage device 7.
When the image is stored in the upper area, the image controller 2 reserves an area in the window buffer 4, transfers an image from the main memory 7 to the window area, and transfers the image to the host processor 6 in the main memory 7. After requesting the release of the area, the specified command is executed. At this time, if a sufficient area cannot be secured in the window buffer 4, the old window area is saved in the main memory 7 as in the case of securing the window area.

(Effect of the Invention) As described in detail above, according to the present invention, when the window buffer of the bitmap display device fills the window area and a new window area cannot be created on the window buffer, the old Since the window image is saved in the main storage device, it is not limited by the number of windows that can be created or the capacity of the window buffer that can be created, and can be increased according to the available main storage area. Further, since the window image that has been recently referred to, that is, may be referred to in the future, is placed in the window buffer that can be operated at high speed, the efficiency of the window operation is not significantly reduced.

Further, in a computer using virtual memory control, it is possible to create a virtually unlimited number of windows by saving window images in the virtual space.

[Brief description of drawings]

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 5 ... CRT 6 ... Host processor 7 ... Main memory device 8 ... System bus

Claims (1)

[Claims] 1. A bitmap display device, which is connected to a main memory and a host processor by a system bus and has a window buffer for storing each window image for the purpose of multi-window display, wherein each window image in the window buffer A first means for detecting the oldest referenced one; a second means for transferring an old window image to the main storage device based on the detection result of the detection means when the window buffer becomes full; A bit map display management system characterized in that a third means for transferring the window image to the window buffer again when a command is issued from the host processor to the window image transferred to the device is provided.