JPS62102288A - Bit map display unit - 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 [Field of Application of the Invention] The present invention relates to a bitmap display device that displays a single character or figure in color.

[Background of the invention]

A display using a bitmap method in which all pixel information representing at least one screen on a display screen is stored in a frame memory, and the contents of the frame memory can be rewritten to display characters and figures. The device is known. In the Kalbitmap display device, one character figure (hereinafter referred to as an image)
In order to display colored images, each elemental information is made up of multiple components representing different primary colors. Usually, multiple frame memories are used to store a specific primary color component in each frame memory, and the information is read from each frame memory. The resulting primary colors are combined for each pixel, and each pixel is colored as desired. In this case, each frame memory area that stores only specific primary color components may be called a plane.

FIG. 3 is a block diagram showing a conventional example of a bitmap display device that performs such a colored display, in which 1 is a central processing unit (hereinafter referred to as a central processing unit) that reads and writes information representing characters, figures, etc. to a frame memory. , abbreviated as CPU), 2 is a CRT control device (hereinafter abbreviated as CR'l'C) that periodically reads information stored in the frame memory and performs control to update the contents of the display screen. ,
3 is the address signal generated by CPU 1, 4 is the CRTC
2 is the address signal generated, 5 is the address signal 3 when the CPU 1 reads/writes the frame memory, and the CRTC
2 is an address selector which selects the address signal 4 and supplies it to the frame memory when reading the frame memory for updating the display screen; 6 is the address signal selected by the address selector 5; 7 is the corresponding position on the display screen. A frame memory (hereinafter referred to as R plane) that stores information representing whether or not the color component of pixel information includes red for one screen.
.

8 is a frame memory (hereinafter referred to as
9 is a frame memory that stores the blue component (hereinafter referred to as B plane), 10 is write data generated by the CPU 1 to peripheral devices such as frame memories 7 to 9, and 11 is data written by the CPU 1. A write plane selection register (hereinafter abbreviated as WPS) for selectively writing to frame memories 7 to 8; 12 is read data of the CPU 1; 13 is red component data read from the R plane 7; 14 is a write plane selection register (hereinafter abbreviated as WPS); Green component data read from the G plane 8, 15 blue component data read from the B plane 9, 16 read plane selection for selecting only one of the data signals 13 to 15 representing each color component and supplying it to the CPU 1. A register (hereinafter abbreviated as Rps), 17 is a display tie generated by CRTC2 and is a puffer control signal. 18-2 A parallel-to-serial conversion circuit for converting data 13 to 15 representing each color component read from the Otfi frame memories 7 to 9 from parallel to serial to form a video signal; 21 is a C for projecting a video;
This is a display device typified by RT.

This bitmap display device has three frame memories 7 to 9 corresponding to the three primary colors of light, red, green, and blue, and uses additive color mixture to arbitrarily select one color out of eight colors for each pixel. It is designed so that it can be displayed.

Below, the character display procedure in such a conventional example is shown in FIG.
This will be explained using FIG.

First, let's take an example of drawing Fumiko "A" in yellow on a black background.
I9 field 1ha Mu B8 1,700. -According to the principle of additive color, yellow is a mixture of red and green. Therefore, information is made to exist in the part corresponding to the stroke of the letter "A" on R plane 7 and G plane 8, and there is no information in other parts, and information is made to be present in all parts on B plane 9. I have to do it better than not. For this,
As shown in FIG. 4, the R plane 7 and the G plane 8 have bit patterns a'! i-Write, bit pattern b is written to B plane 9. Here bit pattern a
, b represents that the color has no primary color component, and "1" represents that it has a primary color component. Therefore, in R plane 7 and G plane 8, the yellow color is displayed in the part corresponding to the stroke of the character @A'.
" is stored, and bit "0" is stored in other parts. Also, in G plane 9, bit 10' is stored in all parts.
is stored.

In this way, in this conventional example, there are generally six planes, so the CPU 1 must perform bit information writing processing on all of the R plane 7, G plane 8, and plane 9. This writing process is performed by switching each plane according to the item number, and as a result, the writing process is required three times. For this reason, the processing time will be three times longer than when displaying a monochrome image, but if the background color to be displayed is black, only the bits corresponding to the strokes of the character will be processed by 11". There are two bit patterns: one in which all bits are “0”, and the other in which all bits are “0”.
In WPSM, a method is used in which a common bit pattern is used to simultaneously write one of the bit patterns to a plurality of planes, thereby reducing the processing time. According to this, when displaying K, a yellow character °A" on a black background as shown in Figure 3, only the bit corresponding to the stroke of one character @A" is displayed for R plane 7 and G plane 8. By writing a bit pattern that is "1" at the same time, and writing a bit pattern where all bits are 10" to B plane 9, the letter "A" is written in yellow on a black background.
” can be drawn.

The method of writing the same bit pattern to multiple planes at the same time as described above can be used in circuit configurations with more than three planes, but it is only effective when one of the strokes of the character or the background is white or black. ,Moreover, even in this case, writing to the 7-frame memory must be done in two parts: writing one bit pattern and writing the other bit pattern.
Approximately twice as much processing time is required as for a monochrome display with a one-plane configuration.

Next, an example of drawing the letter °A'' in red on a blue background will be explained with reference to FIG.

In order to make the background blue 2 and the stroke of the letter "A" red, only the stroke of the letter "A" should be 1" for the R plane 7.
The bit pattern aF? For G plane 8, write a bit pattern b'4 that sets the entire area where the character "A" should be written as "0", and for B plane 9, write the stroke part of the character "A" as "0". Then, it is necessary to write a bit pattern C in which the background part is 1''.

Therefore, in this example, writing to the frame memory must be performed three times at the beginning, and the processing time is approximately six times longer than for a monochrome display with a one-plane configuration.

In general, 3 or more planes? When performing multi-color display, there are bit patterns in which only one stroke part is set to ``1'', bit patterns in which only the stroke part is set to ``0'', bit patterns in which the entire line is set to 1'', and bit patterns in which the entire line is set to 10''. One of the four bit patterns must be selected and written to each plane. Therefore, even if the method of simultaneously writing the same bit pattern to multiple planes as explained in Fig. 4 is used, the frame memory writing process must be divided into four times and performed according to the item number. It takes about four times as long to process compared to display.

The conventional bitmap display device that performs multi-color display as described above does not take into consideration shortening the processing time required to display one character in color, and the number of display colors increases, the number of display pixels increases, and the resolution decreases. There was a major problem in that the display speed of each increasing character was decreasing.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a bitmap display device which solves the problems of the prior art described above and is capable of displaying a single colored image in the same processing time as monochrome display of a single plane.

[Summary of the invention]

In order to achieve the above object, the present invention provides a register that holds information representing a character 1, a part 2 of a figure, a register that holds information representing a background part, and a character.

A combinational gate circuit is provided that generates a bit pattern to be applied to each plane from a bit pattern representing a figure and the contents stored in these registers. The feature is that it is generated and written simultaneously and in parallel.

Examples of the invention] Is the following an example of the present invention? This will be explained with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a bitmap display device according to the present invention,
is a character color register that stores information indicating whether the stroke part of the bit pattern written in each plane is set to "1" or "0", and 25.26.27 is the background (stroke part) of the bit pattern written in each plane. The part that is not “
A background color register that stores information indicating whether to set it to 1" or "0", 28% 29.30 is the memory content of the character color register 22, 25, 24 and background color register 25, 26, 27 and the CPU 1, respectively. This is a combinational gate circuit that generates a bit pattern to be input to each plane from a bit pattern representing the shape of a character supplied from the circuit, and parts corresponding to the third time are given the same reference numerals.

Next, the character writing procedure (i-) in this embodiment will be explained with reference to FIG.
Assume that the processing word length of PU1 is 8 bits.

Obviously, the same applies to other values, such as 16 bits, 32 bits, 64 bits, etc.

As in FIG. 5, we will take as an example a case where the stroke of the letter "A" is displayed in red and the background is displayed in blue. C
Processing word length of PU 1? 8 bits, character "A" has a size of 8 pixels in height and width on the display screen, CPUI
Since one pixel can be represented by one bit of information, in order to display the character "A", K must write eight bits each into the frame memory eight times. In the conventional example shown in FIG. 3, this write process must be performed for each plane, which requires a total of 24 writes. Furthermore, since the bit pattern to be written is different for each plane, it is necessary to determine which bit pattern should be written to which plane, and also to generate the bit pattern to be written to each plane.

Conclusion 4: Compared to a single plane monochrome display, the processing time was three to four times longer.

In this embodiment shown in FIG. 1, when the CPLJl performs a write operation on the frame memories 7.8, 9, the bit pattern to be supplied to each plane is automatically determined by the combinational gate circuits 28, 29, 30. These bit patterns are then simultaneously written to the corresponding planes, so the CPU 1 only needs to write eight bits each eight times, and there is no need to generate a bit pattern for each plane.

For this purpose, first of all, the text color register 22.25
．． 24 and background color registers 25, 26, and 27. In other words, if the presence of one envelope component is expressed as lighting, and the absence of a color component is expressed as off, then the 1 character color register 22 and the background color register 25 turn on and off the respective stroke parts of the bit pattern to be written to the R plane 7. , which controls lighting/extinguishing of the background part, and writing "1" in each means means lighting, and writing "0" means turning off. Similarly, the 1st character color register 23 and the background color register 26 correspond to the G plane 8, and the 1st character color register 24 and the background color register 27 correspond to the B plane 2), and the character color and background color of each plane are turned on. , to control lights out.

Text color register 22, 25, 24 and background color register 2
The outputs of 5, 26, and 27 become inputs of combinational gate circuits 28, 29, and 30 provided corresponding to each plane 7° 8.9. In addition to the outputs of these character color registers 22, 23, 24 and background color registers 25, 26, 27, a bit pattern supplied by the CPU 1 is commonly input to the combinational gate circuit 28° 29% 30, and these three For each input bit operation, bit patterns to be input to the corresponding planes 7, 8, and 9 are generated. In the bit pattern supplied by CPU 1, the bit corresponding to the stroke part of one character is @1'', and the bit corresponding to the background part is ``0#'', but there is a correspondence between "1" and @O. may be reversed.

In combinational gate circuit 28.29.3o.

On the other hand, the output of text color registers 22, 23, 24 and the CPU
A logical AND with the bit pattern supplied from 1 is generated, and on the other hand, the output of the background color register 25.26°27 and C
Negation of the bit pattern supplied from PU1 (that is, all 11" bits included in this bit pattern @
0', all bits of @0'' are replaced with "1#"), and the logical sum of the two logical products obtained in this way? Each plane 7.8.9 is provided as a bit pattern to be written. At this time, 1 character color register 2
If the content of 2.23.24 is @1m, the "1" bit included in the bit pattern supplied from CPU 1, that is, the bit corresponding to the stroke part, remains 11', and each plane 7.8 .9 is supplied to 1 character color register 2
If the content of 2.25.24 is "0", it is changed to "0" before each plane 7.8.9 is supplied. If the content of background color register 25.26.27 is @0'', C
10″ included in the bit pattern supplied from PU1
, that is, the bits corresponding to the background part are 10
" is supplied to each plane 7.8.9 as is, and if the background color register 25.26.27 (7) content is 51",
@1'' and then supplied to each plane 7.8.9.

In the example shown in FIG. 2, in order to set the text color to red, only the text color register 22 corresponding to R plane 7 is set to 1", and the text color registers 23 and 24 are set to "0". In order to set the background color to blue, only the background color register 27 corresponding to the B plane 9 is set to K "1", and the background color registers 25 and 26 are set to 10".

After this, when a bit pattern representing a character is written from the CPUI, a bit pattern in which only the stroke of the character lights up (that is, "1") is written to R plane 7, and to G plane 8. A bit pattern is written in which the entire character is turned off (that is, it becomes "Q"), and for B plane 9, only the stroke part of the character is turned off (that is, it becomes "0"), and the background part is turned on ( In other words, the focus pattern (which becomes "1") is written. As a result, on the display device 21, the character is displayed using additive color mixture, with the stroke part of the character being red and the background part being blue.

Text color register 22.23.24 and background color 25.2
6.27, once set, there is no need to perform any further operations until the color settings are changed. Therefore, once the color setting is performed, character display can be performed in exactly the same processing time as in the case of monochrome display of a single plane.

[Embodiments of the invention]

As described above, according to the present invention, bit patterns for each frame memory can be generated and stored simultaneously, and the process for writing bit patterns can be performed simultaneously. ! Time I
vff can be significantly shortened and multicolor display can be realized at the same processing speed as monochrome display.

In addition, since the display processing procedure for five-character figures is the same as for monochrome display after color setting, the character display program is simple and easy to develop and maintain. Since only a few parts are added compared to the conventional method, it is possible to avoid complicating the structure and increasing costs, and other excellent effects can be obtained.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a bitmap display device according to the present invention, FIG. 2 is an explanatory diagram showing character display operation in this embodiment, and FIG. 3 is an example of a conventional bitmap display device. The block diagram, FIG. 4, and FIG. 5 are explanatory diagrams each showing the character display operation in this prior art. 1...CPU, 7.8.9...Frame memory, 2
2.25.24...Text color register. 25.26.27...Background color register. 28.29.30...Combination gate circuit. Representative Patent Attorney Katsuo Ogawa (Figure 5)

Claims (1)

[Claims] It includes a central processing unit that performs drawing processing of characters and figures, a display device, and a plurality of frame memories, each of which has a different specific color component in each pixel of one screen of the display device. A bit pattern consisting of bits representing the frame memory is stored, and the bit patterns read from each of the frame memories are combined and supplied to the display device, thereby displaying characters and figures in multiple colors. In the map display device, first and second storage means for storing one word consisting of a predetermined number of bits for each frame memory, and characters and figures output by the central processing unit and to be displayed on the display device. The part “
1" logical operation means for performing a logical operation on the output read out word by word from the first and second storage means on a bit pattern consisting of bits whose background portion is "0"; only the first storage means corresponding to the frame memory in which the bit pattern for the specific color component included in the character or figure portion to be displayed is stored and all bits are set to "1"; By setting all the bits stored in only the second storage means corresponding to the frame in which the bit pattern for the specific color component included in the background part to be displayed is to be stored to "0" among the storage means, A bitmap display device characterized in that the bit pattern to be stored in each of the frame memories can be simultaneously obtained from the logical operation means.