JP2530880B2 - Graphic display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention interprets and executes a drawing command sequence given from a higher-level processing device and draws a graphic in an image memory. Display device

(Prior Art) Conventionally, a plurality of drawing engines are provided, and drawing commands to be processed by these drawing engines are shared and processed in parallel, or memory bits forming one pixel (for example, 8 bits / pixel). There is a graphic display device in which the processes are shared and processed in parallel. In such an apparatus, the end of the command sequence is detected by polling the status of each drawing engine or receiving a drawing command end interrupt from each drawing engine.

By the way, in a parallel processing type graphic display device, there are a case where a plurality of drawing engines generate one same image, and a case where each drawing engine generates a different image and combines and displays them. When one same image is generated by a plurality of drawing engines, it is necessary to synchronize the drawing command processing of the plurality of drawing engines in order to prevent the display screen from being disturbed. On the other hand, when the respective drawing engines generate different images and synthesize and display them, it is not necessary to establish such synchronization.

In the conventional device, such control is performed only by software processing, and there is a problem in ensuring both performance and synchronization of drawing.

(Problems to be Solved by the Invention) The present invention has been made in view of such problems, and an object thereof is to (a) add a plurality of drawing engines by adding a simple configuration. Achieve both of drawing synchronization when used to generate one image, and (b) improvement of drawing performance when drawing independent images using multiple drawing engines and combining and displaying them. It is to realize a graphic display device capable of performing.

(Means for Solving the Problems) The present invention for solving the above problems includes a plurality of drawing engines having a function of interpreting and executing a drawing command string given from a higher-level processing device and drawing in an image memory. In the graphic display device, an AND circuit that inputs drawing end notifications from the plurality of drawing engines, an OR circuit that inputs drawing end notifications from the plurality of drawing engines, and an AND circuit from the AND circuit. A signal and a signal from the logical sum circuit are selected according to a method of image generation, and an interrupt mode changeover switch for providing the selected signal as an interrupt signal to the upper processing device is provided.

(Operation) When drawing one object image, the changeover switch selects the signal from the AND circuit as an interrupt signal, and when combining and displaying independent images, it outputs the signal from the OR circuit. Select it as an interrupt signal. This reduces the overhead of interrupt processing of the host processor.

(Example) Hereinafter, the example of the present invention is described in detail using drawings.

FIG. 1 is a configuration block diagram showing one embodiment of the present invention. In the figure, 1 is a high-order processing device, and 21 and 22 are a plurality of drawing engines having a function of interpreting and executing a drawing command string given from the high-order processing device 1 via a system bus SB and drawing in an image memory. Then, here, the one provided with two drawing engines is shown.

Reference numerals 31 and 32 are image memories in which image data to be drawn is written by receiving signals from the corresponding drawing engines 21 and 22, respectively.

Reference numeral 4 is a color lookup table for inputting signals from the image memories 21 and 22, and reference numeral 5 is a display engine for reading out the image data stored in the image memories 21 and 22 and guiding it to the color lookup tables. Here, the display engine 5 is configured to change the mapping of the color lookup table 4 in real time so as to perform two types of window type displays, for example, 8 bits / pixel and 4 bits / pixel two-screen composite display. ing.

Reference numeral 6 is a display means such as a CRT for displaying the display data from the color lookup table 4. These configurations are similar to those of a known graphic display device.

71 is a logical product circuit for inputting drawing end notifications from a plurality of drawing engines 21 and 22, 72 is a plurality of drawing engines
An OR circuit for inputting drawing end notifications from 21 and 22, respectively, 8 selects a signal from the AND circuit 71 and a signal from the OR circuit 72 according to the method of image generation, and selects the selected signal. It is an interrupt mode changeover switch that is given to the higher-level processing device 1 as an interrupt signal.

Here, for example, when the drawing engines 21 and 22 draw in a 4-bit / pixel 2-screen window, the changeover switch 8 is connected to the contact a side, selects the signal from the AND circuit 71, and outputs 8 bits / pixel. In the case of drawing in the window (each drawing engine 21 and 22 takes charge of 4 bits each and draws the same image together), the changeover switch 8 is connected to the contact b side and the signal from the OR circuit 72 is connected. Is to be selected.

 The operation of the device configured as described above will be described below.

First, a case of drawing an 8-bit / pixel screen will be described. In this case, the changeover switch 8 is
It is connected to the contact b side by a command from the host processor 1. In addition, the drawing engines 21 and 22 are
Except for color data, it receives almost the same drawing command sequence and processes it. During this processing, if the processing of the drawing command sequence is out of synchronization, for example, the drawing engine 21
If the processing of 1 is delayed, an undefined code appears in the composite image, which causes flicker or disorder in the image. In the apparatus of the present invention, the drawing completion notifications in the drawing engines 21 and 22 are given by the OR circuit 72 and the changeover switch 8.
Is applied as an interrupt to the host processor 1 via the. Upon receiving this interrupt, the upper processing device outputs a command such as waiting for an event so that the two drawing engines operate in synchronization.

Next, in the case of drawing in a window for combining 4 bits / pixel 2 screens, the changeover switch 8 is connected to the contact a side in response to a command from the host processing device 1. In this case, the drawing engines 21 and 22 may operate independently, and the respective drawing completion notifications are independently given to the higher-level processing device 1 via the AND circuit 71 and the changeover switch 8.

As described above, the high-level processing device 1 connects the changeover switch 8 to the contact b side so that the signal from the logical sum circuit 72 can be given as an interrupt when drawing an 8-bit / pixel screen, and the drawing command string Each drawing engine 21,22
When the drawing end interrupt is received, the changeover switch 8 is connected to the contact a side to prevent the deterioration of the performance due to the disturbance of the display due to the drawing synchronization failure.

Although two drawing engines are used in the above, a larger number of drawing engines may be used. In this case, the completion of drawing from a plurality of drawing engines involved in displaying one image is input to the logical sum circuit and the logical product circuit,
The output is given as an interrupt to the upper processing unit 1.

(Effects of the Invention) As described in detail above, according to the present invention, synchronization of drawing when a plurality of drawing engines are used to generate one image and independent images using a plurality of drawing engines. It is possible to realize both of the improvement of the drawing performance in the case of drawing an image and displaying the combined image by adding a simple configuration.

[Brief description of drawings]

FIG. 1 is a configuration block diagram showing an embodiment of the present invention. 1 ... High-order processing device 21, 22 ... Drawing engine 31, 32 ... Image memory 71 ... Logical product circuit 72 ... Logical sum circuit 8 ... Changeover switch

Claims (1)

(57) [Claims] 1. A graphic display device having a plurality of drawing engines having a function of interpreting and executing a drawing command sequence given from a higher-level processing device and performing drawing in an image memory, wherein drawing from the plurality of drawing engines is performed. An AND circuit that inputs the end notifications, an OR circuit that inputs the drawing end notifications from the plurality of drawing engines, and a signal from the AND circuit and a signal from the OR circuit for image generation. A graphic display device comprising: an interrupt mode changeover switch for selecting a signal from a higher-order processing device according to the method and giving the selected signal as an interrupt signal to the higher-order processing device.