JPH03102395A - Character display system - Google Patents

Abstract

PURPOSE:To utilize a software resource effectively by adding hardware for character display processing. CONSTITUTION:A 1st processing means 124 retrieves a pattern data storage means 121 according to an input character code and specifies an address of a character pattern 122 corresponding to an input display position to write retrieved pattern data. An address storage means 123 is stored with the address specified at the time of the writing processing by the 1st processing means 124 and outputs a readout request signal when the address is stored. A 2nd processing means 131 generates data in picture element units which show a figure and performs figure display processing for storage in a picture element data storage means 11, and pattern data stored in the character buffer 122 is transferred to a picture element data storage means 111 at a readout request according to the address stored in the address storage means 123.

Description

[Detailed Description of the Invention] [Table of Contents] Overview Industrial Field of Application Conventional Technology Problems to be Solved by the Invention Examples of Means and Actions for Solving Problems ■. Correspondence between the example and FIG. 1 ■. Structure of the example■. Operation of the embodiment■. Summary of Examples■. Variations of the Invention Effects of the Invention [Summary] The purpose of this invention is to provide a pixel data storage means for storing pixel data, and a method for storing pixel data in the pixel data storage means, for the purpose of effectively utilizing software resources regarding a character display method in a graphic display device. a graphic display means having a display means for displaying based on pixel data, a pattern data storage means for storing pattern data representing characters and symbols, and a character batza for storing the pattern data at a specified address. and a first processing means for specifying the address of the character buffer corresponding to the manually entered display position and writing the pattern data retrieved from the pattern data storage means based on the input character code; Address storage means that sequentially stores addresses specified during write processing and outputs a read request signal when at least one address is stored; performs graphic display processing to be stored in the pixel data storage means, and in response to the read request signal, based on the address stored in the address storage means,
and second processing means for transferring the pattern data stored in the character buffer to a corresponding storage location in the pixel data storage means.

[Industrial application field]

The present invention relates to a character display method in a graphic display device.

2. Description of the Related Art As display devices for workstations used in computer-aided design (CAD) systems and the like, graphic display devices that place emphasis on graphic display functions are used.

Since graphic display devices mainly display graphics, some graphic display devices do not have a character display mechanism like that used in character display devices.

On the other hand, there is a desire to display kanji characters in such graphic display devices as well as in character display devices.

[Conventional technology]

FIG. 5 shows the structure of a workstation equipped with a conventional character display device. Further, FIG. 6 shows the structure of a workstation equipped with a conventional graphic display device.

In a workstation equipped with a conventional character display device, when displaying characters, a microprocessor (
The character code indicating the character to be displayed is stored by the MPU 5 1 1 in the storage location of the character buffer 512 corresponding to the position where the character is to be displayed. The display control unit 513
Read the character code from this character buffer 512,
The data is supplied to the character generator CCG') 5 1 4. According to this character code, pattern data representing the corresponding character is output from the CG 514, converted into a video signal, and displayed on a cathode ray tube (CRT) 515.

In this way, a workstation equipped with a character display device is premised on having a character display mechanism consisting of the character buffer 512 and the CG 514.

Furthermore, character display devices are more popular than graphic display devices, and the amount of software that is applied to workstations and personal computers that use character display devices has accumulated to an enormous extent.

On the other hand, in a workstation equipped with a conventional graphic display device, the MPU 621 stores pixel data representing a graphic in the graphics memory 622 based on input coordinate data and drawing instructions. Display control unit 6
23 is a CRT 6 2 so as to perform display based on the pixel data stored in the graphics memory 622.
It is designed to control 4.

[Problem to be solved by the invention]

By the way, the conventional graphic display device described above does not have a character buffer or CG, so it is not possible to display characters by using the software applied to a workstation equipped with a character display device as is, and a huge amount of data is required. There was a problem that software resources could not be utilized.

When attempting to display characters using the above-mentioned graphic display device, each character must be represented as a graphic.

Also, if you simply add a character buffer and CG,
MPU6 of workstation using graphic display device
Since it is necessary to control the character buffer and CG by 2.1, the program related to character display must be significantly changed.

The present invention was created in view of the above points, and an object of the present invention is to provide a character display method that makes effective use of software resources by adding hardware for character display processing. It is said that

[Means to solve the problem]

FIG. 1 is a block diagram of the principle of the character display system of the present invention.

In the figure, the graphic display means 110 includes a pixel data storage means 111 that stores pixel data, and a display means 112 that performs display based on the pixel data stored in the pixel data storage stage 111.

The pattern data storage means 121 stores pattern data representing characters and symbols.

Character buffer 122 stores pattern data at a designated address.

The first processing means 124 searches the pattern data storage means 121 based on the input character code, specifies the address of the character buffer 122 corresponding to the manually input display position, and writes the retrieved pattern data. Process.

The address storage means 123 sequentially stores addresses specified during the write process by the first processing means 124, and outputs a read request signal when at least one address is stored.

The second processing means 131 normally performs a figure display process of generating pixel data representing a figure and storing it in the pixel data storage means 111, and stores it in the address storage means 123 in response to a read request signal. Based on the address
Processing is performed to transfer the pattern data stored in the character buffer 122 to the corresponding storage location in the pixel data storage stage 111.

[For production]

Based on the input character code, the first processing means 124
Accordingly, the corresponding pattern data is retrieved from the pattern data storage means 121, and this pattern data is stored at the address of the character buffer 122 corresponding to the input display position.

At this time, the address of this character buffer 122 is stored in the address storage stage 123, and when at least one address is stored, this address storage means 123 outputs a read request signal. For example, the read request signal may be output when addresses are stored up to half of the capacity of the address storage stage 123.

In response to this read request signal, the second processing stage 131 stores the character buffer 1 stored in the address storage means 123.
The pattern data stored at address 22 is transferred to the corresponding storage location in pixel data storage stage 111.

In the present invention, the first processing means 124, the pattern data storage means 12l, the character buffer 22, and the address storage means 123 operate as a character display mechanism that performs processing for character display. Further, in response to a read request signal from the address storage means 123, the second processing stage 131 transfers the pattern data stored in the character buffer 122 to the pixel data storage stage 111, thereby converting characters and symbols. Based on the pattern data represented, the display means 1
12 is displayed. Thereby, without significantly changing the software of the second processing means 131, it is possible to utilize software resources that have been carefully prepared on the premise that a character display mechanism is provided.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 2 shows the structure of a workstation to which a character display method according to an embodiment of the present invention is applied.

■． Here, the correspondence between the embodiment of the present invention and FIG. 1 will be shown.

The graphic display means 110 corresponds to the graphic display device 210.

The pixel data storage means 111 is a graphics memory 21
Corresponds to 2.

The display means 112 corresponds to a cathode ray tube (CRT) 211.

The pattern data storage means 121 corresponds to the pattern data area 232 of the memory 223.

The 1,000 character buffer storage stages 122 correspond to the character buffer area 233 of the memory 223.

The address storage means 123 is a first-in first-out memory (F
IFO) 222.

The first processing means 124 is a microprocessor (MPU)
Corresponds to 221.

The second processing means 131 corresponds to the MPU 201.

Examples of the present invention will be described below assuming that the correspondence relationship as described above exists.

In Figure 2, 201 is a 32-bit microprocessor (MPU), 210 is a graphic display device, and 211 is a 32-bit microprocessor (MPU).
is a cathode ray tube (CRT), 2 1 2 is a graphics memory, 213 is a display control section, and 214 is a signal conversion section. The work station is configured with each of these parts, and the MPU 201 and the graphic display device 210 are
They are interconnected via a bus 202.

Graphic display device i! In each storage location of the graphics memory 2l2 of 210, pixel data is stored corresponding to each pixel of the display screen of the CRT 211.

The pixel data stored in the graphics memory 212 is converted into a video signal by a signal conversion unit 214 and supplied to the CRT 2 1 1, and the display control unit 213 Based on the data, the CRT 2 1 1 and the signal converter 214 are controlled so that the CRT 2 1 1 displays an image.

In addition, 221 is a 16-bit MPU, 222 is a first-in first-out memory (FIF○) with a capacity of 512 words,
223 is a memory having a capacity of IM bytes, and 224 is a status register.

The character display adapter 220 is equipped with each of these parts, and the MPU 221 and memory 223 are connected via a bus 224 consisting of an address bus 224a and a data bus 224b. Also, FIFO222
is connected to the address bus 224a of the MPU 221, and when the MPU 221 writes data to the memory 223, the address of the memory 223 is written to the FIFO 222.

Further, this character display adapter 220 is configured to be inserted into an expansion slot (not shown) of the workstation, and via this expansion slot, the FIFO 22
2, memory 223, status register 224, MP
It is connected to the bus 202 of U201.

The memory 223 stores programs. It is formed of a pattern area 231, a pattern data area 232, and a character buffer area 233.

In this program area 231, when starting up the workstation, a program related to character display processing in the operating system (OS) is stored from an auxiliary storage device (not shown) such as a disk device. .

MPU 221 operates according to a program stored in program area 231 in response to a character display processing request from an application program being executed by MPU 201 . Here, this program area 2
The program related to character display processing stored in 31 is as follows.
This program is the same as the program when using a conventional character display device.

In the pattern data nodding area 232, pattern data representing the corresponding characters and symbols is stored in advance in correspondence with character codes representing the characters and symbols. Further, such pattern data may be stored in advance in the above-mentioned auxiliary storage device, and this pattern data may be stored in the pattern data area 232 when starting up the workstation.

The character buffer area 233 is formed from a plurality of small areas corresponding to each character display position on the display screen of the CRT 211. For example, for CRT2 1 1, 80 digits x 24
If it is possible to display characters in a line, character buffer area 2
33 is formed from 80×24 small areas.

When displaying characters in the application program executed by the JLJ group D Hama Akira Kurasho MPU 201, the application program determines the character code to be displayed and the display in response to a blog regarding character display processing. Specify the position and request character display processing.

In response to this character display processing request, the character display adapter 22
The MPU 221 of No. 0 searches the pattern data area 232 of the memory 223 based on the specified character code, and stores the corresponding pattern data in a small area of the character buffer area 233 corresponding to the specified display position. At this time, the start address of the small area where the pattern data was written is F? Written to FO222.

In this way, in response to a character display processing request from an application program, pattern data corresponding to a specified character code is stored in the character buffer area 233, and the start address of the storage location of pattern data in this character buffer area 233 is stored in the FIFO 222. The characters are sequentially stored in , and character display processing is performed.

FIF○222 outputs the output terminal OHF when the above-mentioned address is written up to half the capacity (256 words).
The half-full signal SHF is configured to output a logic "0" as a half-full signal S■, and this half-full signal SHF is supplied to the MPU 201 as an interrupt request signal and also sets the change notification flag of the status register 224. It is supposed to be done.

In response to the above-mentioned interrupt request signal, the MPU 201
Performs the interrupt processing described below.

FIG. 3 is a flowchart representing interrupt processing operations.

First, the MPU 201 refers to the status register 224 of the character display adapter 220 and determines whether it is necessary to change the display screen of the CRT 2 1 1 based on whether the change notification flag is set (step 3
01).

Here, changing the display screen refers to displaying new characters, changing or erasing displayed characters.

If the change notification flag is set, an affirmative determination is made in step 301 described above, and the MPU 201 reads the address of the character buffer pJf area 233 from the FIFO 222 (step 302), and reads the address from the corresponding small area of the character buffer area 233. The pattern data is read (step 303).

Next, the MPU 2 0 1 calculates the start address of the area of the graphics memory 212 corresponding to the corresponding display position on the display screen of the CRT 2 1 1 based on the address of the character buffer area 233 read out in step 302. Stay in this area? The pattern data read out in step 303 is stored (step 304).

In this way, the pattern data read from the character buffer area 233 is stored in the corresponding area of the graphics memory 212, thereby changing the display screen of the CRT 211.

The MPU 201 receives the half/full signal S of the FIFO 222.
■ becomes logic “1” and status register? The change notification flag of 24 is reset, and step 301 described above is executed.
The processes of steps 301 to 304 described above are repeated until a negative determination is made.

Also, as an interrupt request signal to the MPU 201, the FI
Instead of the half-full signal SHF of FO222, FI
An empty signal S which becomes logic "1" when the FO 222 is in an empty state may be used. In this case, the status register 224 may set the above-mentioned change notification flag when the entity signal St is at the logic "°O".

By the way, the reading speed of the address from the FIFO 222 by the MPU 201 is faster than that of the FIF by the MPU 2 2 1.
If the writing speed to O222 is faster, the address is F.
The IFO 222 is now written to its full capacity. At this time, the FIFO 222 receives a full signal S from the output terminal OF.
y is set to output logic "0", and this full signal Sy is supplied to the MPU 221 as a hold signal S HOLD.
is this hold signal S0. The operation is temporarily stopped while L,) is at logic "0".

In this way, when addresses are written to the full capacity of the FIFO 222, the MPU 222
The character display processing operation according to No. 1 is temporarily stopped.

On the other hand, when refreshing the screen or canceling input data, the MPU 201 outputs a reset signal Sヮ to the control terminal R of the FTP0222.
supply to. The FIFO 222 resets the write position of the address in response to the reset signal S supplied to the control terminal R, and outputs logic "1" as the half-full signal SNF and the full signal SF described above. There is.

Further, the change notification flag of the status register 224 is reset in accordance with the change in the half/full signal SNF.

Further, as described above, there are cases where it is desired not to temporarily stop the MPU 221 in a state where addresses are written to the full capacity of the FIF○ 222.

In this case, the MPU 201 performs the interrupt processing shown in FIG. 4 in response to the interrupt request signal supplied from the FIFO 222. In addition, in this case, when the full signal SF of the FIFO 222 is logic +1 0 1+, the full notification flag of the status register 224 is set, and the logic "
Make sure to reset it when it is 1.

First, the MPU 2 0 1 uses the status register 224
It is determined whether the full notification flag is set (step 401), and if the determination is negative, the CRT2
1. It is determined whether or not it is necessary to change the display screen of 1 (step 402). In the case of an affirmative determination in step 402, the MPU 201 reads the address from the FIFO 222 (step 403), reads the pattern data from the character buffer area 233 based on this address (-step 404), and stores the data in the graphics memory 212. It is stored in the corresponding area (step 405).

In the same manner as when the MPU 221 is temporarily stopped by the full signal S2 described above, steps 401 to 405 are repeated until a negative determination is made in step 402.

On the other hand, in the case of an affirmative determination in step 401, MP
U201 outputs the above-mentioned reset signal SR and
Reset the writing position of O222 (step 406)
, refreshes the entire screen (step 407),
After executing step 407, the process returns to step 401.

■ Conclusion As mentioned above, a character display adapter 220 equipped with an MPU 221, a FIFO 222, a memory 223, and a status register 224 is added to a workstation equipped with a graphic display device 210, and a pattern is stored in the pattern data area 232 of this memory 223. Data is stored, and a program related to character display processing is stored in the program area 231 and started.

As a result, the MPU 221, FIFO 222,
Processing for character display is performed by the memory 223, and pattern data corresponding to the specified character code is stored in the character buffer area 233 of the memory 223. Additionally, an interrupt request signal (
This pattern data is transferred to the graphics memory 212 by performing the above-mentioned interrupt processing in response to the half/full signal SHy of FIF0222.
The CRT 2 1 1 of the graphic display device 210 makes it possible to display characters based on pattern data.

In this way, character display can be performed without changing the application program by simply adding the above-mentioned interrupt processing program to the MPU 201 program.

Further, the character display adapter 220 described above is a commercially available MP
This can be done using elements such as U, FIF○, and memory.

〔Effect of the invention〕

As described above, according to the present invention, the first processing means, the pattern data storage means, the character buffer, and the address storage means perform character display processing, and the second processing means performs processing for displaying the pattern data stored in the character buffer. By transferring the data to the pixel data storage means, it becomes possible to display characters using the display means, and it is possible to utilize software resources that assume the existence of a character display mechanism, which is extremely useful in practice. .

[Brief explanation of drawings]

Figure 1 is a principle block diagram of the character display method of the present invention, Figure 2
The figure is a block diagram of a workstation to which a character display method according to an embodiment of the present invention is applied, Figures 3 and 4 are flowcharts showing the interrupt processing operation of the embodiment, and Figure 5 is a conventional character display device. Fig. 6 is a block diagram of a workstation equipped with a conventional graphic display device. In the figure, 110 is a graphic display means, 111 is a pixel data storage means, 112 is a display means, 121 is a pattern data storage means, 122 is a character buffer, 123 is an address storage means, 124 is a first processing means, and 131 is a second processing means. Processing means, 201, 221, 511, 621 are microprocessors (MPU), 202, 224 are buses, 210 are graphic display devices, 211, 515, 624 are cathode ray tubes (CRT), 212
．． 622 is graphics memory, 213,513.62
3 is a display control unit, 214 is a signal conversion unit, 220 is a character display adapter, 222 is a first-in first-out memory CFIF○), 223 is a memory, 231 is a program area, 232 is a pattern data area, 233 is a character buffer area, 512 is a character Buffer 514 is a character generator (CG). Paralyzed - 7-line display device Makihachikan 5th figure? , T car■ Figure 6

Claims (1)

[Claims] (1) Pixel data storage means (11
1), and display means (112) that performs display based on the pixel data stored in the pixel data storage means (111).
), a pattern data storage means (121) storing pattern data representing characters and symbols, and a character buffer (121) storing the pattern data at a designated address.
2) Search the pattern data storage means (121) based on the input character code, specify the address of the character buffer (122) corresponding to the input display position, and retrieve the searched pattern data. a first processing means (124) for performing a write process, and sequentially storing addresses specified during the write process by the first processing means (124);
Address storage means (123) that outputs a read request signal when at least one address is stored, and a graphic display that generates pixel data in pixel units that usually represent a figure and stores it in the pixel data storage means (111). processing, and in response to the read request signal, the address storage means (
a second processing means (131) for transferring the pattern data stored in the character buffer (122) to a corresponding storage location of the pixel data storage means (111) based on the address stored in the character buffer (123); A character display method characterized by being configured to include and.