JPH01276196A - Image display controller - Google Patents

Abstract

PURPOSE:To reduce the size and cost of a device by selecting plural image display devices with a selection signal and storing attribute information on an image to be displayed on the devices in a selected frame memory. CONSTITUTION:When a CPU 1 sends a task switch command to a graphic controller 3, the controller 3 interprets the command and actuates a task switch 3a. Then necessary and sufficient information for the processing of a task 0 which is stored previously in a register group 3b is transferred to an area 4a assigned for the task 0 in a TCB 4. Then an area 4b assigned to a task 1 in the TCB 4 is transferred to the register group 3b in the controller 3. The controller 3 selects the attribute information on the image from respective memory areas in order and stores them in frame memories 5a-5c, and it is displayed on CRT display devices 7a-7c.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an image display control device that simultaneously displays multiple types of images on multiple image display devices under the control of a single graphic controller. be.

[Conventional technology]

FIG. 5 is a block diagram showing the configuration of a conventional image display control device. In FIG. 0, (1) is a host CPU,
(2) is the main memory for storing programs, data, etc. of the Konohost CPU (1), (7), (3) is the graphic controller, (5) is the frame memory for storing data to be displayed on the CRT display device, and (6) is the main memory for storing programs, data, etc. The D/A converter (7) is a CRT display device.

Next, the operation of the conventional device will be explained based on the above configuration.

When the host CPU (1) sends a drawing command to the graphics controller (3), the graphics controller (3) interprets the drawing command and rewrites (draws) the frame memory (5) based on the drawing command. Display image data (application software) is periodically read out from the frame memory (5) by the graphic controller (3), and the data is converted into an analog video signal by the D/A converter (6). Output to CRT display device (7). Also, the graphics controller (3) is CR
It generates timing signals such as horizontal synchronization signals and vertical synchronization signals to the T display device (7).

[Problem B to be Solved by the Invention] Conventional image display control devices are configured as described above, so when it is desired to simultaneously display multiple types of application software that are processed in parallel on multiple image display devices. As shown in Fig. 6, one CRT control device is required for each application software, and it becomes extremely costly to realize an image display control device that can display multiple types of application software simultaneously. At the same time, there was a problem in that the device itself became larger.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an image display control device that is small in size and can display a plurality of images simultaneously at low cost.

[Means for Solving the Problems] An image display control device according to the present invention includes a plurality of image display devices, a frame memory corresponding to each of these image display devices, and attribute information of an image displayed on each image display device. is stored in the memory area corresponding to each image display device, and selects the corresponding memory area, frame memory, and image display device from the memory based on the area selection information output from the microprocessor, and also selects the corresponding memory area, frame memory, and image display device based on the attribute information. A graphics controller that generates display image information and stores it in a selected frame memory is provided.

[Effect]

When a selection signal of an image display device for displaying an image is inputted from a microprocessor, a graphic controller according to the present invention transmits attribute information of an image to be displayed on the corresponding image display device based on the selection signal to the image display device. Select from memory area and send to frame memory. Therefore, even if multiple types of images are displayed simultaneously on each of multiple image display devices, the graphics controller selects attributes corresponding to each image display device from each memory area based on selection signals input sequentially from the microprocessor. By selecting information and sending it to the frame memory, a single graphics controller can control the display of multiple image display devices simultaneously.

(Example) Hereinafter, an example of the present invention will be explained with reference to the drawings.
In the figure, (1) is the host CP Ll, (2)
is the main memory, (3) is the graphics controller,
(3a) is a task switch device, (3b) is a register group, (4) is a TCB (task control box)
, (4a), (4b), and (4c) are the areas allocated to tasks 0, 1, and n, respectively, and (5a)
, (5b) and (5c) are task 0.1, respectively.
...Frame memory for n, (6a), (6
b), (8c) are tasks 0.1,...n, respectively
D/A converter for (7a), (7b),
(7c) is a CRT display device for tasks 0.1, . . . n, respectively, and (8) is a CRT control device.

Next, the operation will be explained. The case of causing a task switch from task O to task 1 will be described. host c
p U (1) is the graphics controller (3)
When a task switch command is sent to the graphics controller (3), the graphics controller (3) interprets the command and activates the task switch device (3a). Then, the information necessary and sufficient for the processing of task 0 previously stored in the register group (3b) is transferred to the area (4a) allocated to task 0 in the TCB (4). Then, after transfer, T
Area (4) allocated to task 1 in CB (4)
b) to the register group (3b) in the graphics controller (3).

If this situation were drawn as a flowchart, it would look like Figure 2.

Here, the information necessary and sufficient for task processing includes, for example, the number of bits of pixels, foreground color, background color, line type, current pointer, and the like.

In this way, multiple application software each assigned a task can jointly use one graphics controller using this task switch function.
It becomes possible to draw in each frame memory.

However, frame memory (5a), (5b),
(5c) is read out, and the CRT display device (7a),
The timing signals for outputting to (7b) and (7c) may all be common.

In the above embodiment, each application software is displayed on a separate CRT display device, but the application software can be displayed on the same CRT display device in a window like the one shown in FIG. It may also be done using

Furthermore, in the above embodiment, the graphic controller (3) as shown in FIG. 4(a) performs a task switch when it receives a task switch command from the host CPU (1), but the host CPU Figure 4 (1) gives the graphic controller (3)
b) A task number may be assigned to each command string as shown in (b), and the graphic controller (3) checks the task number each time and performs task switching only when it differs from the current task number.

Further, in the above embodiment, a case has been described in which a plurality of application software are processed by the same host CPU, but each application software may be processed by separate host CPUs connected to the same system bus. It has the same effect as.

〔Effect of the invention〕

As described above, according to the present invention, the graphic controller sequentially selects a plurality of image display devices based on the image display device selection signal sent from the microprocessor, and at the same time displays images on the selected image display device. Since the configuration is such that image attribute information is sequentially selected from each memory area and stored in the frame memory, it is possible to simultaneously display multiple types of images on multiple image display devices using the graphics controller in the office. It is possible to realize an image display control device that is simple, inexpensive, and miniaturized.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an image display control device according to an embodiment of the present invention, FIG. 2 is a flowchart showing the operation of this embodiment, and FIG. 3 is a CRT showing another embodiment of the invention.
4 is a diagram showing a command sequence showing another embodiment of the present invention. FIG. 5 is a block diagram showing a conventional image display control device. FIG. 6 is a diagram showing a conventional image display control device. FIG. 2 is a block diagram showing a device that displays a plurality of application software using the device. In the figure, (1) is the host CPU. (3) is a graphic controller, (3a) is a task switch device, (4) is a task control box, (5a) to (5)
c) is frame memory, (7a) to (7c) are CRT
Display device. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] A plurality of image display devices, a frame memory corresponding to each of these image display devices, a memory that stores attribute information of images to be displayed on each image display device in a memory area corresponding to each image display device, and a microprocessor. Selecting the corresponding memory area, frame memory, and image display device from the memory based on the area selection information output from the
An image display control device comprising: a graphics controller that generates display image information based on attribute information and stores it in a selected frame memory.