JPS63245781A - Multilevel image memory access device in bit map display device - Google Patents

Abstract

PURPOSE:To speed up processing and to simplify constitution by developing supplied data into a state repeated in a prescribed direction by the prescribed number of times, supplying the developed data to a picture memory and writing a part of the developed data. CONSTITUTION:At the time of data writing operation in a pixel mode, a 1st data buffer part 12 is selected by a mode analysis part 11 and 16-bit data for two pixels supplied from a processor to the buffer part are developed to a state repeated in the (x) direction by 8 times. Only the data of 2X8 bits corresponding to a pixel selecting signal outputted from a selection signal forming part 15 out of said data is written in the picture memory. At the time of data writing operation in a plane mode, a 2nd buffer part 13 is selected and the data of 16 bits continued in the pixel direction are similarly developed to a state repeated in the (Z) direction by 8 times and only the data of 16 bits out of these data is written.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a multivalued image memory access device in a bitmap display device, and more specifically,
a number of bits arranged in a first direction;
One frame is made up of a large number of bits arranged in a second direction perpendicular to the direction, and the bit has a screen memory that represents the color data of each pixel with a plurality of bits in a third direction perpendicular to both directions. The present invention relates to a multi-valued image memory access device for accessing a multi-valued image memory having a plurality of planes in correspondence with pixel mode, fill-in mode, and plane mode in a map display device.

<Prior Art> Bitmap display devices capable of accessing data pixel by pixel have been widely used as display devices capable of high-quality display of not only characters and figures but also images.

Recently, in order to perform color display, a large number of bits are arranged in a first direction (hereinafter referred to as the X direction) and a second direction orthogonal to the X direction.
A frame consisting of a large number of bits arranged in the direction of In order to represent the color data of each pixel, a configuration is adopted in which a plurality of frame memories are installed side by side. That is, the frame memory corresponds to a three-dimensional matrix.

When accessing a frame memory with such a configuration, for example, if the data bus on the processor side is 16 bits wide and the frame memory has an 8-plane configuration, image data can be written to and read from the frame memory in units of 16 bits. By doing so, the time required to access the entire frame memory can be shortened.

However, when accessing a frame memory having the above three-dimensional matrix configuration, even if the writing/reading unit of image data specified by the processor is 16 bits, the actual writing/reading unit for the frame memory is 16 bits. Since 16 x 8 = 128 bits, it is necessary to write or read only the necessary 16 bits out of 128 bits, and control for this is required.

To explain in more detail, the type of access to the frame memory is when accessing consecutive 16 bits in the X direction in any plane at the same time (
There is also a case (pixel mode and fill-in mode) in which image data of all planes corresponding to multiple pixels (total 16 bits) is accessed simultaneously (pixel mode and fill-in mode). Therefore, the write or read data must be processed.

In consideration of these points, conventionally, after reading 16 x 8 bits of pixel data including the address specified by the processor from the frame memory, processing is performed only on the necessary 16 bits, and the pixel data is read out from the frame memory again. When writing to 16x8 bits, only the above 16 bits are updated based on the processed data, and the remaining 14 x 8 bits or 16 x 7 bits are written to 16 x 8 bits by using the above read data as is. The data was written to the frame memory as data.

To explain in more detail, (1) When reading image data in pixel mode, in this case, 16 x 8 bit data is read from the frame memory, and the necessary 2 bits out of 16 bits in the X direction are read out. Only 2×8 bits of data (data for 2 pixels) can be supplied to the processor through the data bus.

Therefore, the color can be checked based on the data for the two pixels, and if necessary, the data for the two pixels can be stored in another memory.

(II) When writing image data in pixel mode In this case, read 16 x 8 bit data from the frame memory and select the location where 2 pixels worth of data supplied from the processor should be written. By writing 16 x 8 bits of data together into the frame memory with 2 pixels worth of data updated,
Color data for two desired pixels can be updated.

If the above two pixels already store color data, the color data will be updated, and if no color data is stored, new color data will be written, but there is no essential difference at all. .

Therefore, by sequentially performing the above operations, all color data in a desired area can be updated.

(G) When writing specific color data in fill-in mode In this case, the point in (I[) above is that the color data for 2 pixels supplied from the processor is the preset specific color data. It only differs from case to case.

Therefore, similarly to the case (II) above, the color data of the desired area can be unified with specific color data set in advance.

(Incorporated) When reading image data in plane mode, in this case, 16 x 8 bit data is read from the frame memory, and 16 x 8 bits of data is read in the
Only bits of data can be supplied to the processor through the data bus.

Therefore, the color elements can be checked based on the 16-bit data, and if necessary, the 16-bit data can be stored in another memory.

When writing image data in M plane mode, in this case, 16 x 8 bit data is read from the frame memory, and the 16 bit data supplied from the processor is overwritten in the location corresponding to the plane to be written. , 1 with 16-bit data updated
By collectively writing 6×8 bit data to the frame memory, 16 bit color element data of a desired plane can be updated.

<Problems to be Solved by the Invention> In the bitmap display device with the above configuration, if only data is to be read, the frame number needs to be accessed only once, but when data is to be written, If so, there is a problem in that the frame memory needs to be accessed twice, and the entire process takes a long time.

To explain in more detail, the unit of data processing by the processor is 16 bits, while the unit of writing and reading from the frame memory is 16 x 8 bits.
Moreover, whether the above 16 bits correspond to the 16 bits in the X direction or in two directions depends on the type of processing, so once the above 16
It is necessary to read the bit data, override only the 16 bits to be processed with new 16 bit data, and then write the data into the frame memory again in units of 16×8 bits.

That is, a series of operations of reading, updating, and writing (hereinafter referred to as RMW
(abbreviated as ) is required, so the frame memory must be accessed twice as described above, and the entire process takes a long time.

In addition, in RMW, since the processing order must be accurately controlled, management by the processor (by software) is essential, and from this aspect as well, there is a problem that the overall processing speed cannot be increased. There is.

Furthermore, in order to perform RMW, data latches, multiplexers, buffers, management processors, and the like are required, making the configuration complicated.

<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 multilevel image memory access device that can achieve overall high-speed processing as well as a simplified configuration.

Means for Solving the Problems> In order to achieve the above object, the multi-valued image memory access device of the present invention writes multi-bit color data in the third direction of the screen memory in units of at least one pixel. , or a fill-in mode in which a plurality of preset color data is written in the third direction of the screen memory corresponding to a pixel mode for reading and a predetermined bit out of the plurality of bits in the first direction of the screen memory. a first data conversion means for converting data for the mode; writing image data in a plurality of bits at a time in a first direction of the screen memory;
Alternatively, a second data conversion means performs data conversion for a plain mode for reading, and stores multi-bit color data for a fill-in mode;
color data storage means for supplying color data to the first data conversion means when performing fill-in mode; pixel mode;
or selection signal generation means for selectively generating a pixel selection signal for selecting an accessible pixel for fill-in mode and a plane selection signal for selecting an accessible plane for plane mode; and an external mode signal. The apparatus includes mode control means for analyzing the mode based on the signal from the generation source and controlling the above-mentioned data conversion means, color data storage means, and selection signal generation means based on the analysis result.

However, it is preferable that the first data conversion means develops the multi-bit color data supplied for writing in the pixel direction, and the second data conversion means preferably Preferably, the multi-bit data supplied for writing in the first direction of the memory is expanded in the plane direction.

Function> The multivalued image memory access device having the above configuration has a large number of bits arranged in the first direction, and
One frame is made up of a large number of bits arranged in a second direction perpendicular to the direction, and the bit has a screen memory that represents the color data of each pixel with a plurality of bits in a third direction perpendicular to both directions. In the map display device, when reading in pixel mode, readable pixels are selected based on the pixel selection signal output from the selection means, and only the selected pixels are read out through the first data conversion means. color data can be read.

When writing in pixel mode, data supplied from the processor is converted into data to be written to the screen memory by the first data conversion means, and then a pixel is selected based on a pixel selection signal output from the selection means. color data can be written only to pixels that have been

When writing in the fill-in mode, the color data stored in the color data storage means is supplied to the first data conversion means, so that the color data is outputted from the selection means after being converted into write data for the screen memory. Color data can be written only to pixels selected based on a pixel selection signal.

When reading in plane mode, a readable plane is selected based on a plane selection signal output from the selection means, and data of only the selected plane is read through the second data conversion means. be able to.

When writing in the plane mode, the data supplied from the processor is converted into write data for the screen memory by the second data conversion means, and then the plane selection signal is selected based on the plane selection signal output from the selection means. Data can be written only to the plane that has been set.

Furthermore, when the first data conversion means is one that develops the multi-bit color data supplied for writing in the pixel direction, the supplied multi-bit color data is treated as the same color data. In this state, one set of color data is written only to pixels selected based on a pixel selection signal output from the selection means. Can be done.

Further, when the second data conversion means expands the supplied multi-bit data for writing in the first direction of the screen memory in the plane direction, the supplied multi-bit data can be developed into a state in which a large number of data are lined up in the third direction as the same data, and in this state, one set of data can be developed only for the plane selected based on the plane selection signal output from the selection means. Can be written.

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

FIG. 7 is a block diagram showing a schematic configuration of a bitmap display device including a multivalued image memory access device of the present invention, in which a system bus (5) is connected to a processor (
3), main memory (4), and mode control section (1)
is connected. A screen memory (2) is connected to the mode control section (1). Furthermore, the transfer control unit (
6) to a refresh memory (7), and data read from the refresh memory is supplied to a CRT display (9) via a video control section (8).

Therefore, the processor (3) can exchange data with the main memory (4) or the mode control section (1) through the system bus (5).

Furthermore, when the processor (3) accesses the screen memory (2), the mode control unit (1) controls the data width of the system bus (5) and the screen memory (2).
This is to adjust the difference in the access data width of 2), and converts the data of a predetermined data width supplied through the system bus (5) into a fairly wide access data width and transfers the data to the screen memory (2). It also converts data with a fairly wide access data width read from the screen memory (2) into data with the data width of the system bus (5) and sends it to the processor (3). It is possible to read data.

Then, the processor (3) via the mode control unit (1)
The data stored in the screen memory (2) in which predetermined image data is stored is transferred to the transfer control unit (6).
By supplying the data read from the refresh memory (7) to the CRT display (9) via the video control section (8), a color image can be visually displayed. Can be done.

Figure 1 shows the mode control section (
1) is a block diagram showing in detail the configuration of 1), which includes a mode analysis section (11), a first data buffer section (12), a second data buffer section (13), and a color register section (
14) and a selection signal generation section (15).

To explain in more detail, the mode analysis section (11) determines which mode, pixel mode, fill-in mode, or plane mode, is specified based on the mode signal supplied from the processor (3) through the system bus (5). Based on the analysis results, the first data buffer section (12), second data buffer section (13), color register section (14), and selection signal generation section (15) are It is something to control.

The color register section (14) stores 8-bit color data corresponding to a preset writing color, and stores 8-bit color data in the first register only when fill-in mode is selected. The data is supplied to the data buffer section (12).

The first data buffer unit (12) converts between input and output data when pixel mode or fill-in mode is selected. Specifically, the first data buffer unit (12) converts input and output data from the processor (3) to When 16-bit data is supplied, 7 more sets of the same data as the above 16-bit data are generated, the 16-bit data is developed into 8 sets, and the developed data is stored in the screen memory (2). We are trying to supply the following. When 8-bit color data is supplied from the color register section (14), 15 sets of color data identical to the above 8-bit color data are generated, and 16 sets of the above 8-bit color data are lined up. The data is expanded into a screen memory (2) and the expanded data is supplied to the screen memory (2).

The second data buffer section (13) converts between input and output data when the plain mode is selected, and specifically, the second data buffer section (13) converts between input and output data when the plain mode is selected.
When 16-bit data to be written to the plane is supplied, seven more sets of data identical to the above 16-bit data are generated, expanded into eight sets of the above-mentioned 16-bit data, and stored in the screen memory ( 2) is supplied with expanded data.

The selection signal generation section (15) receives address data supplied from the processor (3) and the mode analysis section (11).
) It outputs the necessary pixel selection signal and plane selection signal based on the analysis results supplied from (supplied to the second data buffer unit (13)), specifically, when pixel mode or fill-in mode is specified, pixel selection that allows writing or reading of only two pixels to be accessed. Conversely, when a plane mode is specified, a plane selection signal is generated to select a plane to be accessed. In addition, -20 above
= Processor (3) no matter which mode is specified.
The start address data of the 16-bit area in the X direction is generated based on the address data supplied from the
And out of the 8-bit area in two directions, which pixel the data corresponds to and which plane the data corresponds to are determined based on the pixel selection signal or plane selection signal. Become.

The operation of the mode control section (1) having the above configuration is as follows.

(1) Data write operation in pixel mode In this case, the mode analysis section (11) selects the first data buffer section (12).

Therefore, the processor (
3) to 2 pixels worth of 16-bit data (a) (b
) (see Figure 2C) is the first data buffer section (12).
The above data (a) and (b) are expanded in this order in the X direction (pixel direction) eight times and sent to the screen memory access bus. .

In this case, based on the address data supplied from the processor (3), the selection signal generation section (15) writes a pixel selection signal for two pixels (see FIG. 2C) into the screen memory (2) as a write permission signal. Therefore, out of the 16 x 8 bit data mentioned above, only the 2 x 8 bit data corresponding to the write permission signal is written into the write permission pixel area of the screen memory (2) (see the second diagram).
.

Hereafter, by repeating the above series of operations, 2
Multivalued image data can be written in a predetermined area of the screen memory (2) in units of pixels.

As is clear from the above explanation, when writing in pixel mode, there is no need to read data from the screen memory (2) and update data only to the desired part of the read data; Since it is only necessary to write to pixels, there is no need for software management, the number of accesses to the screen memory is reduced, and the overall time required for writing multivalued image data can be shortened.

(U) Data read operation in pixel mode Also in this case, the first data buffer section (12) is selected by the mode analysis section (11).

Therefore, based on the address data supplied from the processor (3), the corresponding 16×8 bit data is
(See Figure 3C)
. Note that the above 16 x 8 bit data is set so that the unit of access to the screen memory is every 16 bits in the X direction, so 2 pixels specified by the processor (3) are An access unit containing minutes of data is selected.

Then, based on the address data supplied from the processor (3), the selection signal generation section (15) reads out a pixel selection signal for two pixels (see FIG. 3C) and uses it as a pixel selection signal to the first data buffer section ( 12), of the 16 x 8 bit data, only the 2 x 8 bit data corresponding to the read pixel selection signal is sent to the system bus (5) (see Figure 3C). It is taken into the processor (3). As a result, the processor (
In step 3), in addition to being able to confirm the color of the two pixels, the captured data can also be stored in the main memory (4) or the like.

Hereafter, by repeating the above series of operations, 2
Multivalued image data can be read out from a predetermined area of the screen memory (2) in units of pixels.

(2) Data write operation in plain mode In this case, the mode analysis section (11) selects the second data buffer section (13).

Therefore, the processor (
3) 16-bit data (C) (
C) is supplied to the second data buffer unit (13), and the data (C) is expanded in this order in two directions (plane direction) in a state where it is repeated eight times, and then transferred to the screen memory access bus. (See Figure 3C).

In the second case, the selection signal generation unit (15) supplies the plane selection signal (see FIG. 4C) as a write permission signal to the screen memory (2) based on the address data supplied from the processor (3). Therefore, of the 16×8 bit data, only the 16 bit data corresponding to the write permission signal is written to the write permission plane of the screen memory (2) (see the fourth diagram).

Hereafter, by repeating the above series of operations, 1
Image data can be written in 6-bit units to a predetermined plane of the screen memory (2).

As is clear from the above explanation, when writing in plain mode, there is no need to read data from the screen memory (2) and update data only to the desired part of the read data; simply write the data to the desired location. Since it is only necessary to write to pixels, there is no need for software management, the number of accesses to the screen memory is reduced, and the overall time required for writing multivalued image data can be shortened.

Data Read Operation in Plain Mode Also in this case, the second data buffer section (13) is selected by the mode analysis section (11). Therefore, based on the address data supplied from the processor (3), the corresponding 16×8 bit data is read into the second data buffer section (13) (see FIG. 3C). In addition, the above 16×
Since the 8-bit data is set so that the access unit to the screen memory is every 16 bits in the X direction, the 16-bit data specified by the processor (3) can be accessed in any plane. selected as a unit.

Then, based on the address data supplied from the processor (3), the selection signal generation section (15) reads out the plane selection signal (see FIG. 3C) and uses it as the second plane selection signal.
Of the 16 x 8 bit data, only the 16 bit data corresponding to the read plane selection signal is supplied to the system bus (13).
5) (see FIG. 5C) and taken in by the processor (3). As a result, in processor (3),
In addition to being able to confirm the color elements of 16 pixels corresponding to the 16 bits mentioned above, the captured data can also be stored in the main memory (4) or the like. That is, the screen memory (
R, for the 16×8 bit read data from 2).
G.

It can be read as data in units of 16 bits by filtering B. After reading data in units of 16 bits eight times, the desired data can be read in units of 16 bits for each plane by performing the circle operation described above. can be written.

Thereafter, by repeatedly performing the above series of operations, image data can be read out from a predetermined area of the screen memory (2) in units of 16 bits in each plane.

M Data write operation in fill-in mode In this case, the mode analysis section (11) writes the first data buffer section (12) and the color register section (14).
) is selected.

Therefore, 8-bit data (d) (see FIG. 6C) is supplied from the color register section (14) to the first data buffer section (12), and the data (d) is supplied to X in this order.
It is expanded into a state that is repeated 16 times in the direction (pixel direction) and sent to the screen memory access bus (see FIG. 6C).

In this case, the selection signal generation section (15) supplies a pixel selection signal (see FIG. 6C) as a write permission signal to the screen memory (2) based on the address data supplied from the processor (3). Therefore, of the 16.times.8 bit data, only each 8 bit data corresponding to the write permission signal is written into the write permission pixel area of the screen memory (2) (see the sixth diagram).

Hereafter, by repeating the above series of operations, 8
Image data can be written in bit units to a predetermined area of the screen memory (2). In this case, data is not supplied from the processor (3) through the system bus (5), but one pixel worth of data is supplied from the color register section (14), so a maximum of 16 pixels is supplied. Color data can be written for a predetermined number of pixels up to.

As is clear from the following explanation, when writing in the fill-in mode, the operation of reading data from the screen memory (2) and the operation of updating only the desired part of the read data are completely unnecessary, and the operation is simply performed. Since it is only necessary to write to desired pixels, software management is not required, the number of accesses to the screen memory is reduced, and the time required for writing multivalued image data can be shortened as a whole.

To summarize above, no matter which mode is selected, access to screen memory (2) is as follows:
Since only one write or one read is performed, the processor (
3), there is no need to manage the processing order at all, so the configuration can be simplified, and each read and write that was required in the case of conventional RMW is now performed only once. Only reading or writing is required, and the overall processing time can be significantly shortened.

It should be noted that the present invention is not limited to the above-described embodiment; for example, it is possible to set the data width in the system bus to a width other than 16 bits and to set the number of planes to a number other than 8. In addition, various design changes can be made without changing the gist of the invention.

<Effects of the Invention> As described above, the present invention provides information on the difference between access data of a predetermined number of bits and data of a predetermined number of bits for screen memory access in the case of pixel mode or fill-in mode and in the case of plain mode. In addition to converting data, the data to be actually accessed to and from the screen memory is selected based on the pixel selection signal and plane selection signal, so the series of operations of reading, updating, and writing is performed. It is sufficient to simply read or write without having to read or write, which has the unique effect of significantly shortening the overall time required and simplifying the configuration.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a block diagram showing an embodiment of the multilevel image memory access device of the present invention, FIGS. 2 to 6 are schematic diagrams explaining access operations, and FIG. 1 is a block diagram showing the configuration of a bitmap display device including a value image memory access device. FIG. (1)...mode control unit, (2)...screen memory,
(3)...Processor, (II)...Mode analysis section, (I2)...First data buffer section, <13)
...Second data buffer section, (14)...Color register section, (15)...Selection signal generation section

Claims (1)

[Claims] 1. One frame is composed of a large number of bits arranged in a first direction and a large number of bits arranged in a second direction perpendicular to the first direction, and writing a plurality of bits of color data in the third direction of the screen memory in units of at least one pixel in a bitmap display device having a screen memory representing color data of each pixel with a plurality of bits in a third direction, each perpendicular to the second direction; Alternatively, there is a pixel mode in which reading is performed, and a fill-in mode in which color data of a plurality of bits preset in the third direction of the screen memory is written in correspondence with a predetermined bit among the plurality of bits in the first direction of the screen memory. a first data conversion means that performs data conversion for a plain mode, and a second data conversion means that performs data conversion for a plain mode that writes or reads image data in a first direction of the screen memory in units of multiple bits. means for storing a plurality of bits of color data for the fill-in mode and supplying the color data to the first data converting means when performing the fill-in mode; selection signal generation means for selectively generating a pixel selection signal for selecting an accessible pixel for the plane mode and a plane selection signal for selecting an accessible plane for the plane mode; and a signal from an external mode signal source. A multivalued bitmap display device characterized in that it has a mode control means for analyzing the mode based on the analysis result and controlling both the data conversion means, the color data storage means, and the selection signal generation means based on the analysis result. Image memory access device. 2. The multivalued image memory in the bitmap display device according to claim 1, wherein the first data conversion means develops the multi-bit color data supplied for writing in the pixel direction. Access device. 3. The bitmap according to claim 1, wherein the second data conversion means expands the plurality of bits of data supplied for writing in the first direction of the frame memory in the plane direction. A multivalued image memory access device in a display device.