JPS63245780A - Picture memory access device - Google Patents

Abstract

PURPOSE:To access a picture memory without changing an address area by converting reading/writing data from/in a picture memory into code data having the number of bits less than that of the reading/writing data to access the picture memory. CONSTITUTION:In case of accessing the picture memory 1 from a picture memory access function part 2, the color data of picture elements read out from the memory 1 are inputted and converted into coded data having the small number of bit by an input preprocessing part 3 and the formed coded data are supplied to the access function part 2. The access function part 2 executes discrimination and sort processing and supplies the processed result to an output post-processing part 4. The data supplied to the output post-processing part 4 are converted into color data having the original number of bits and a writable signal is formed and supplied to the picture memory 1.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a screen memory access device, and more specifically, to a screen memory that stores image data pixel by pixel in a bitmap display device.
The present invention relates to a device that accesses a screen memory pixel by pixel in order to fill in a predetermined area, draw line segments within a predetermined area, etc.

<Prior art> Conventionally, in a bitmap display device, image data is stored in a screen memory, and a part of the image data stored in the screen memory is written to a frame memory, so that the contents of the frame memory are updated. A configuration in which an image is displayed on a display device based on the information is generally adopted.

When changing the image to be displayed, basically the image data stored in the screen memory is first changed,
The image displayed on the display device is changed by writing the changed image data into the frame memory. In this case, if you want to change the entire image, it is necessary to transfer new image data from the main processor and write it to the screen memory, but if you want to change the image partially, for example in a predetermined area. When performing coloring, drawing line segments within a predetermined area, etc., a display control unit (hereinafter referred to as screen memory access function unit) is used to make the above partial changes based on instructions from the main processor. It would be a good idea to set it up.

As a screen memory access function unit to achieve such functions, it has traditionally had an address area not smaller than the screen memory, handles data read from the screen memory as actual color information, and processes instructions from the main processor. A device was used that had a function of performing discrimination and classification processing based on the color information, generating color information for filling in, drawing line segments, etc., and writing it to the screen memory in units of pixels.

<Problems to be Solved by the Invention> In the screen memory access device configured as described above, the address area of the screen memory access function section is determined according to the size of the screen memory, or the screen memory access function section is There is a problem in that the size of the screen memory is limited by the address area of .

To explain in more detail, in the current situation where there is a strong trend toward increasing resolution and multi-functionality such as multi-window functions in bitmap display devices, it is natural that increasing the screen memory capacity is an essential requirement. Therefore, if the size of the screen memory is limited by the address area in the screen memory access function section,
Since either of the above-mentioned increases in resolution or multi-functionality such as multi-window function cannot be achieved, if the capacity of screen memory is increased, it is necessary to have an address area that can access the entire area of screen memory. Requires use of screen memory access functionality. However, the screen memory access function section is usually composed of an LSI and cannot easily cope with an increase in the address area, so it is usually forced to use the screen memory with a limited capacity. There is a problem with putting it away.

<Object of the invention> This invention was made in view of the above problems,
It is an object of the present invention to provide a screen memory access device that can access a wide screen memory without increasing the address area in a screen memory access function section.

Means for Solving the Problems> In order to achieve the above object, the screen memory access device of the present invention has a screen memory access function by degenerating data read from the screen memory into coded data of a predetermined number of bits. and output post-processing means that receives output data from the screen memory access function section and generates write data and a write control signal for the screen memory.

However, the input pre-processing means includes a color information holding circuit in which a predetermined number of color information is set in advance, and a match determination between the read data from the screen memory and the color information set in the color information holding circuit. Part 6- It is preferable to have a match determination circuit and a coding circuit that receives a determination signal from the match determination circuit as input and generates coded data of a predetermined number of bits.

In addition, the output post-processing means includes a drawing color information holding circuit in which a predetermined number of drawing color information is preset, and a drawing color selection signal that receives code data output from the screen memory access function section and outputs a drawing color selection signal to the screen. It is preferable to have a code recognition circuit that generates a write permission signal for the memory, and a drawing color information output circuit that selects corresponding drawing color information based on a drawing color selection signal.

Function> With the screen memory access device having the above configuration, when the screen memory in which color image data is stored is accessed by the screen memory access function unit having functions such as discrimination and classification processing, the screen memory access device has the following functions: By degenerating the read data into coded data of a predetermined number of bits by the input preprocessing means and supplying it to the screen memory access function unit, the screen memory access function unit performs discrimination, classification processing, etc. based on the coded data. It will be done. That is,
Since coded data has fewer bits than data read from screen memory, the pixels of screen memory that can be accessed according to the degree of degeneration even if the address area in the screen memory access function section does not change. The number will increase.

Then, using the output data from the screen memory access function section as input, the output processing means generates write data for the screen memory and a write control signal and supplies them to the screen memory, so that the write data corresponding to the output data is sent to the pixel. Can be written to screen memory in units.

That is, it is possible to generate actual inspection data with a large number of bits based on output data with a small number of bits, and to control actual writing based on the write permission signal. is data based on actual color information.

Further, the input preprocessing means performs a match between a color information holding circuit in which a predetermined number of color information is set in advance and the read data from the screen memory and color information set in the color information holding circuit. If the device has a match determination circuit and a coding circuit that receives a determination signal from the match determination circuit and generates coded data of a predetermined number of bits, the color information holding circuit is set in advance. A match determination circuit determines whether or not the two match based on the color information in the image and the data read from the screen memory, and a determination signal is supplied to the encoding circuit to generate a predetermined bit corresponding to the determination result. A number of encoded data can be generated and provided to the screen memory access function. Therefore, by increasing or decreasing the types of color information preset in the color information holding circuit, it is possible to change the degree of degeneracy when encoding.

Further, the output post-processing means inputs a drawing color information holding circuit in which a predetermined number of drawing color information is preset, and code data output from the screen memory access function section, and generates a drawing color selection signal and a screen memory. If the device has a code recognition circuit that generates a write permission signal for the screen memory, and a drawing color information output circuit that selects the corresponding drawing color information based on the drawing color selection signal, the screen memory Using the code data output from the access function section as input, the code recognition circuit generates a drawing color selection signal and a write permission signal for the screen memory, and the drawing color information output circuit, which is controlled based on the drawing color selection signal, reads the code data. By selectively outputting color information corresponding to and supplying it to the screen memory, it is possible to write the selected color information only to pixels corresponding to the write permission condition.

<Example> Hereinafter, embodiments will be described in detail with reference to the accompanying drawings showing examples.

FIG. 1 is a block diagram showing the configuration of the screen memory access device of the present invention, in which an input pre-processing section (3) and an output post-processing section are provided between the screen memory (1) and the screen memory access function section (2). Section (4) has been established.

The above-mentioned screen memory (1) has image data written in pixel units and can change data in pixel units.

The screen memory access function section (2) performs discrimination and classification processing on a pixel-by-pixel basis based on the image data stored in the screen memory (1), and outputs processing result data. The number of bits of data and the number of bits of input data are fixed and equal.

The input preprocessing unit (3) receives the color data of each pixel read from the screen memory (1) as input, generates coded data with a small number of bits based on preset color information, and displays the The data is supplied to the memory access function section (2).

The output post-processing unit (4) inputs the processing result data with a small number of bits output from the screen memory access function unit (2) and generates color data with the original number of bits, and also generates a write permission signal. and screen memory (1
).

The operation of the screen memory access device having the above configuration is as follows.

Based on the color data read from the screen memory (1), the manual pre-processing unit (3) generates coded data with a small number of bits based on preset color information, and the screen memory access function unit (2) generates coded data with a small number of bits. ).

Then, in the screen memory access function section (2),
Discrimination, classification processing, etc. are performed based on the coded data, and processing result data with a small number of bits is output.

This processing result data is supplied to the output post-processing unit (4), which generates color data with the original number of bits, generates a write permission signal, and generates a screen memory (1
).

Therefore, based on the determination and classification processing results in the screen memory access function section (2), pixels in the necessary locations in the screen memory (1) are replaced with different color data, and
For pixels that do not need to be replaced, the output post-processing unit (4)
By blocking the writing of new color data by the write permission signal output from the , the original color data is kept as it is, so you can fill in the desired area in the screen memory, draw line segments in the desired area, etc. be able to.

FIG. 2 is a block diagram showing in detail the configuration of the input preprocessing section (3), in which the comparison color register (31) holds color information equal to the number of colors that can be recognized by the screen memory access function section (2). ), a comparison circuit (32) that compares the read data from the screen memory (1) with the contents of the comparison color register (31) for each pixel, and (31) A coding circuit (3
3).

The operation of the input preprocessing section (3) having the above configuration is as follows.

In a normal bitmap display device, reading and writing are performed in units of multiple pixels in order to shorten the time required to read and write data to the screen memory (1). In the case of the embodiment as well, data reading is performed in units of 8 pixels, and the screen memory (1) has an 8-plane configuration to store color data, and the screen memory access function section (2) has an 8-plane configuration. It has one type of identification color, and
Assuming that it has two types of writing colors and has an internal color code function, 64 bits of data will be read out in one read operation.

Of the 64-bit read data, the comparator circuit (32)
It is compared with the three data of the comparison color register (31) in the comparison color register (31), and the comparison result data with the three data is supplied to the encoding circuit (33). Therefore, the encoding circuit (3
In step 3), coded data of 2 bits per pixel is generated based on the comparison result data with the above three data, and can be supplied to the screen memory access function section (2).

In this way, coded data for 8 pixels is generated,
After the coded data is supplied to the screen memory access function section (2), the same processing is performed on the next 64-bit read data.

As a result, the 64-bit data read from the screen memory (1) is output from the encoding circuit (33) as 16-bit encoded data.

Therefore, in the screen memory access function section (2), 8 pixels can be accessed with 16 bits (1
Compared to the conventional example (8 bits per pixel) in which two pixels were accessed using 16 bits (2 bits per pixel), four times as many pixels can be accessed even in the same address area.

FIG. 3 is a block diagram showing in detail the configuration of the output post-processing section (4), in which color information equal to the number of colors that can be drawn by the screen memory access function section (2) (in this embodiment, 2
Although three pieces of color information are shown, there may be only one piece of color information, or there may be three or more pieces of color information. However, as the number of types of color information increases, it is necessary to increase the number of bits of the code data output from the screen memory access function section (2), so it is set to an appropriate type that is not too large. The color register (41) and the code data output from the screen memory access function section (2) are input, and a selection signal for selecting the corresponding color information as a drawing color is output, and writing is performed in pixel units. A code data recognition circuit (42) that outputs a permission signal; and a color data selection circuit that receives the selection signal and selects and outputs corresponding color information from among the color information held in the drawing color register (41). (43). Incidentally, both the write permission signal and the color data output from the color data selection circuit (43) are supplied to the screen memory (1).

The operation of the output post-processing section (4) having the above configuration is as follows.

Code data of 2 bits per pixel output as a result of discrimination, classification processing, etc. performed in the screen memory access function section (2) is supplied to the code recognition circuit (42). , the drawing color is recognized and the 2nd color stored in the drawing color register (41) is stored only for pixels that are determined to be newly drawn.
A selection signal indicating which type of color information should be used for drawing is generated, and a write permission signal for each pixel is generated.

The color data selection circuit (43) to which the selection signal is supplied selects one of the two types of color information stored in the drawing color register (41), and selects one of the two types of color information stored in the drawing color register (41). It is supplied to the screen memory (1) as color data.

Therefore, in the screen memory (1), the 8-bit color data output from the color data selection circuit (48) is supplied while the write permission signal for each pixel is being supplied, so that the writing permission signal for each pixel is supplied. You can draw.

That is, the screen memory access function section (2) outputs 2-bit code data corresponding to each pixel, and based on this code data, 8-bit color data can be written to the screen memory (1). Compared to the conventional example in which one pixel was accessed using 8 bits, four times as many pixels can be accessed even in the same address area.

Specifically, as in the case of the input preprocessing circuit (3), the screen memory access function section (2) receives 16 pixels for 8 pixels.
The color data selection circuit (43) outputs 64-bit color data for 8 pixels, and the code recognition circuit (42) outputs an 8-bit write permission signal for 8 pixels. It is output. Therefore, 8 pixels worth of color data corresponding to 8 pixels worth of code data is simultaneously supplied to the screen memory (1), but actually the screen memory (1)
Since the color data to be written in is only for the pixels for which the write condition has been selected out of the write enable signals for 8 pixels, it is possible to write in units of pixels. Note that all (color data) will not be written to pixels for which the write permission signal does not meet the write permission conditions below, so the original color data will be saved as is and will not be written to the screen memory (1). Then, partial correction, etc. of the image data will be performed.

As a result, the 16-bit code data output from the screen memory access function section (2) is output from the color data selection circuit (43) as 64-bit soto color data, and 8-bit soto writing is enabled. It will be output as a signal from the code recognition circuit (42). Therefore, in the screen memory access function section (2),
One pixel can be accessed with 2 bits, and compared to the conventional example in which one pixel is accessed with 8 bits, four times as many pixels can be accessed even in the same address area.

In summary, by converting read data from the screen memory (1) into coded data with a small number of bits and supplying it to the screen memory access function unit (2), discrimination and classification processing is performed based on the coded data. etc. are performed, and a write permission signal corresponding to each pixel of the screen memory (1) and color data for writing are generated and supplied to the screen memory (1) based on the code data as a processing result. Color data is written pixel by pixel; for example, an area surrounded by pixels to which specific color data is written is filled with specific color data, or a specific color is written only to the above area. Operations such as drawing line segments are performed based on the data. In other words, even if the address area necessary for performing discrimination, classification processing, etc. based on read data is used, the number of pixels that can be accessed corresponds to the number of bits for each pixel, which is reduced by encoding. screen memory (1
) can easily cope with the increase in capacity.

In the above embodiment, there is one identification color and two drawing colors.
Since it is a color, the screen memory access function unit (2) performs discrimination and classification processing based on 2-bit coded data, and uses an address area that can be accessed based on 8-bit color data. It is possible to access four times as many pixels as the number of pixels in this state.

Also, instead of increasing the address area of the screen memory access function section (2), an input pre-processing section (3) and an output post-processing section (4) are newly required.
Overall, compared to using a screen memory access function section with a large address area, it is more compact and
Although it may seem that there has been little change in terms of simplification and cost reduction, the screen memory access function itself has a fairly large address area and also has functions such as drawing and coloring. It has an input pre-processing section (3) and an output post-processing section (4).
It only needs to be capable of processing the number of bits in units of reading and writing to the screen memory, and it is significantly smaller than the screen memory access function section (2), has a simple configuration, and is inexpensive. Overall, this makes it possible to achieve greater miniaturization, simplification, and cost reduction than when using an address area or a large screen memory access function.

Note that the present invention is not limited to the above-described embodiments; for example, by setting the number of bits of coded data to an arbitrary number of bits smaller than the number of bits of color data for each pixel in the screen memory, It is possible to set the number of pixels of the accessible screen memory as appropriate, and in this case, it is also possible to change the type of identification color and the type of drawing color in accordance with the number of bits of coded data. Yes, and other changes to the gist of this invention -21
= It is possible to make various design changes within the range.

<Effects of the Invention> As described above, the present invention provides reading from screen memory,
Since the screen memory access function unit performs processing after converting the code data into code data with a smaller number of bits than the number of bits of the write data, the address area determined based on the number of bits of the read and write data mentioned above is changed. This has the unique effect of making it possible to access a wide screen memory without any trouble.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the screen memory access device of the present invention, FIG. 2 is a block diagram showing the configuration of the input pre-processing section in detail, and FIG. 3 is a block diagram showing the configuration of the output post-processing section in detail. figure. (1)...screen memory, (2)...screen memory access function section (3)...input pre-processing section, (4)...output post-processing section, (31)...comparison color register, (32)
... Comparison circuit, (33) ... Encoding circuit, (41
)...Drawing color register, (42)...Code recognition circuit,

Claims (1)

[Claims] 1. Screen menu where color image data is stored It has functions such as discrimination and classification processing. accessed by the screen memory access function section. The screen memory access device that accesses to locate the read data from the screen memory. Degenerate to coded data with a constant number of bits and supplies it to the screen memory access function block. Input preprocessing means and screen memory access The output data from the function section is used as input. Write data to surface memory, and Output post-processor that generates write control signals A screen memo characterized by having steps. Reaccess device. 2. The input preprocessing means inputs a predetermined number of color information. A preset color information retention circuit, Read data and color information from screen memory The same color information as that set in the holding circuit. A match determination circuit that performs match determination, and a match determination circuit that performs match determination. Specified by inputting the discrimination signal from another circuit A code that generates coded data with a number of bits. and a coded circuit. Screen memo according to claim 1 Reaccess device. 3. The output post-processing means generates a predetermined number of drawn erotic images. Retains drawing color information with preset information From the circuit and screen memory access function section Draw the output code data as input. Image color selection signal and screen memory Code recognition that generates a write enable signal Corresponds based on the circuit and drawing color selection signal Drawing color information output to select the drawing color information to be used. The above features include a power circuit. Screen memoria according to claim 1 access device.