JPS6228790A - Storage area access 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] [Summary] When accessing data for superimposing and displaying a required number of image data for screen composition on a screen, which are distributed and stored in a storage area without overlapping each other, Image data is accessed in access units of the same number of pixels, and at least one pixel within the access unit is accessed only for image data to be displayed, taking into consideration the priority order for each access unit. This allows screen data to be generated quickly even if the memory access time is slow.

[Industrial application field]

The present invention relates to a storage area access method, and more particularly, to a storage area access method that enables high-speed generation of screen data even if the access time of a memory or the like is slow.

Screen data displayed on a display screen is usually stored in memory. In some cases, multiple screen composition image data are superimposed on the displayed screen to form a single display screen, but even in such cases, each screen composition image data is stored in one memory. without being superimposed on each other,
Distributed and stored. Even in such a storage mode, it is necessary to configure a screen data supply system to the display device so that screen data can be generated at a high speed that does not interfere with screen display.

[Conventional technology]

As a conventional screen data composite display method, a required number of screen composite image data is stored in memory, and each screen composite image data is accessed in units of access of the same number of pixels to create a screen in which partial screens are superimposed. There is something displayed on the display device.

[Problem that the invention seeks to solve]

According to this method, all of the required number m of image data for screen composition to be displayed on the screen are always read out in the above-mentioned access units, and by performing display control on a pixel-by-pixel basis, it is possible to display an arbitrary display screen.

However, since m data areas must always be read in each access unit, the memory must be read at a very high speed.

The present invention was created in view of the above-mentioned problems, and its purpose is to provide a storage area access method that can generate screen data to be displayed at high speed without increasing the speed of the memory itself. do.

[Means for solving problems]

FIG. 1 shows a block diagram of the principle of the present invention. In this figure, 10 is a memory, and the memory 10 stores a required number m of screen composition image data A1 to 1, each of which is given a priority order.
Am is stored. Reference numeral 11 denotes an access means, which can access m pieces of image data for screen composition using Nl [I pixels as an access unit, and includes pixels to be displayed on the screen in consideration of priorities for each access unit. The system is configured to determine whether or not the image data is the same, and to access the minimum necessary image data.

[Effect]

Each screen composition image data in the memory 10 is accessed by the access means 11 in the above-mentioned access unit. In this access, only the access unit including the pixels to be displayed is accessed, and a composite display of the screen is performed. Since such access control is performed, a high-speed memory unlike the conventional method is not required for screen composite display.

〔Example〕

2 to 4 show an embodiment of the present invention.

20A1...20Am in FIG. 2 are readout control units corresponding to the image data AI...Am for screen composition shown in FIG. is given in advance. Except for the readout control unit A1 having the highest priority, each readout control unit receives a priority output from a readout control unit having the next highest priority, receives a screen address, and outputs a readout address, a readout request, and a mask signal. The readout control unit A1 with the highest priority has the same configuration as the other readout control units, but the priority input given to it is based on the access in which the screen composition image data A1 is included in any access unit (described later). A signal, for example, a low level signal, indicating that all or part of the unit should be unconditionally displayed is supplied.

Both readout control units are configured as follows (
(See Figure 3). Therefore, each component will be explained with Ai added as a subscript.

21A1 is an adder that adds a screen address and a memory address and outputs a read address. The memory address referred to here is the amount of offset needed to make a one-to-one correspondence between the data to be read and the pixels on the display screen.

22Ai is a mask generator that generates a temporary mask signal for the access unit from the screen address signal and the display position signal, ie, the position where the access unit is to be displayed.

23A! is a read request signal in response to a temporary mask signal and a priority input signal from the mask generator 22Ai,
This is a mask synthesizer that generates the main mask signal and the priority output signal.

The memory shown in FIG. 4 is configured to be accessed using a predetermined number N of pixels as an access unit.

The access mode of the present invention under the above configuration will be explained below.

To simplify the explanation, three data items Al, A2 . An example in which A3 is written and displayed on the display screen in the manner shown in FIG. 6 will be described.

Now, image data Al for screen composition in the memory 10.

The readout mode of A2 and A3 is determined by the respective readout control unit 2.
It is assumed that the access unit 30 is accessed as shown in the schematic diagram of FIG. 7 by the read address obtained from the memory addresses 0Aj, 20A2, and 20A3 and the screen address.

At this time, the readout control unit 20A1 generates a temporary mask signal (image data presence/absence display signal) as shown in (7-1) in FIG. 7 from the screen address signal and display position signal. Also, since the priority input signal is a low level signal, the signal from the mask synthesizer 23A1 to (7) in FIG.
-1) is generated as a mask signal and as a priority output signal. Therefore, regarding the screen composition image data A1, the screen portion corresponding to the PAL image data in the access unit 30 to be accessed is displayed on the display screen 12.

Subsequently, the image data PA2 in the access unit 30 to be accessed as described above is accessed as follows, and the screen portion corresponding to the image data of the image data PA2 is displayed on the display screen 12. .

When the access unit 30 as described above is accessed,
Readout control unit 20 for screen composition image data A2
In A2, similarly to the readout control unit 2OA+, the adder 21A2 generates a readout address corresponding to the access unit 30 in the image data for screen composition A2, but this readout address is generated by the mask signal generated as described below. Valid only by.

A temporary mask signal (see (7-2) in FIG. 7) is generated from the mask generator 22A2 that receives the screen address signal and the display position signal, and this signal is sent to the mask synthesizer 23A2 as its priority input signal, that is, the readout control section. 20
From the priority output signal from At, (7
A mask signal as shown in -3), a priority output signal as shown in (7-4) in FIG. 7, and a read request signal are output. The output mask signal is generated by the AND of the inverted signal of the priority input signal and the temporary mask signal, and as described above (only PA2 of the image data of the access unit 30 read from the memory is displayed). Here, if the signal (7-3) is at 0 level throughout the access unit, no read request is generated and unnecessary accesses can be reduced.Also, the priority output signal is the priority input signal and temporary mask. It is generated by ORing with the signal and is supplied to the next priority read control unit 20A3.

As described above, according to the present invention, it is only necessary to access image data that includes pixels that are actually displayed, so unlike the conventional method, access can be performed in parallel for one access unit time, that is, at one time. The memory is no longer required to be fast enough to read out the maximum number of screens that can overlap within an access unit within the time that the pixels displayed are displayed. Therefore, it is possible to generate screen data at high speed without requiring the memory itself to speed up.

In the above embodiment, a case has been described in which each screen composition image data is stored in the same memory, but it is stored in different hardware storage areas so that multiple access units can be accessed at the same time. Even in this case, the present invention does not exclude the case where at least two pieces of screen composition image data to be accessed simultaneously are stored in at least one storage area.

〔Effect of the invention〕

As explained above, according to the present invention, only the access unit that includes the data portion actually provided for display is accessed for each access unit, so the maximum number of screens that can be overlapped for each access unit is different from the conventional method. Compared to a method in which the same number of access units are accessed in their entirety, screen data can be generated at high speed using a low-speed memory. Therefore, a high-speed memory, etc., as in the prior art, is no longer required for the composite display of the screen.

[Brief explanation of drawings]

Fig. 1 is a block diagram of the principle of the present invention, Fig. 2 is a diagram showing the overall configuration of an embodiment of the present invention, Fig. 3 is a detailed diagram of the readout control section, and Fig. 4 is an image for synthesizing the screen into memory. FIG. 5 is a diagram showing an example of how image data for screen composition is stored in memory; FIG. 6 is a diagram showing an example of a display format corresponding to the example of storage format shown in FIG. 5; The figure is a schematic diagram for explaining the present invention through FIGS. 5 and 6. In FIG. 1, 10 is a storage area, 11 is an access means, and 12 is a display screen. Figure 1 Figure 4

Claims (2)

[Claims] (1) In a display method that displays a composite screen superimposed on the display screen by accessing the image data for screen composition in a storage area (10) that stores the required number of image data for screen composition without overlapping, Priority is given to each piece of screen compositing image data to be displayed in advance, and each screen compositing image data can be accessed in an access unit of the same number of pixels (11), and at least one pixel in the access unit is displayed. A storage area access method characterized in that access to memory occurs only when (2) The storage area access method according to claim 1, wherein each of the image data for screen composition is stored in the same memory without overlapping with each other.