JPH082712Y2 - Display controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a display control device, and more particularly, to improvement of a device for automatically generating a character pattern obtained by converting a character code into a memory address. .

<Prior Art> In a conventional display device, when a character pattern converted from a character code to a memory address is automatically generated, the character code is devised so that the memory address where the character pattern is stored is changed. It was configured to be easy to seek.

Specifically, for example, a character pattern is output by processing a character code and using it as a memory address.

<Problems to be solved by the invention> However, according to such a configuration, the curactor code becomes system-specific, and from the viewpoint of software,
It becomes difficult to use general-purpose character codes such as EUC (Extended UNIX CODE) code and JIS code.

Further, when a general-purpose character code is used, a conversion mechanism is necessary because the character code does not linearly correspond to the memory address where the character pattern is stored. Then, if these conversions are performed by software, the processing becomes complicated and the processing takes too long.

The present invention has been made paying attention to such a point, and an object thereof is to provide a display control device capable of automatically generating a character pattern in a short time based on a general-purpose character code. It is in.

<Means for Solving the Problems> In the present invention for solving the above problems, a memory in which character patterns of a plurality of items having different dot configurations are arranged and stored so as to have continuous addresses for each item, A code register for designating a character code; a code converter for converting the character code read from the code register into an address of the memory in which a character pattern is stored and to attribute data including a dot configuration; An attribute register for latching output attribute data, and an address output from the CPU and an address output from the code converter are added based on the attribute data output from the attribute register to generate a read address of the memory Address adder, It is characterized by being composed of and.

<Operation> In the display control device of the present invention, the character code set by the CPU is addressed in a much shorter time than the address calculation processing by software by the circuit configuration of the code register, code converter, attribute register and address adder. Is converted to.

<Example> Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention. In the figure, the CPU 1 sets the character code of the character pattern to be read in the code register 3 via the data bus 2. The code register 3 outputs the set character code to the code converter 4. The code converter 4 converts the character code input from the code register 3 into an address of the memory 7 in which the character pattern is stored, and the character code belongs to what item and has a dot configuration. Convert to attribute data that indicates whether or not there is. That is, the memory 7 is divided into a plurality of areas A to F according to the character pattern items (ASCII, kana, forms, simple figures, external characters, kanji, etc.) as shown in FIGS. 2 and 3, for example. ing. The character pattern is stored in consecutive addresses for each item in a dot configuration (8 × 8, 12 × 8, 16 × 8, etc.) that is different for each item. Therefore, the code converter 4 classifies the character codes of the character pattern set by the CPU 1 according to the storage items of the memory 7 and converts them into attribute data representing the dot configuration, and also calculates an address offset according to the character code. To the storage address of the memory 7. The address converted and output from the code converter 4 is added to one input terminal of the address adder 5. The attribute data is latched by the attribute register 6, and the CPU 1 can read this attribute data via the data bus 2. Then, the CPU 1 knows an access method for reading a desired character pattern from the memory 7 based on the dot configuration data of the attribute data input via the attribute register 6. This is necessary because the dot configuration of the character pattern corresponding to each character code is different and the method of storing the character pattern in the memory 7 area is different as shown in FIGS. 4 (a) and 4 (b). FIG. 4 (a) shows a storage method for one ASCII character, and FIG. 4 (b) shows a storage method for one kana character. Therefore, the CPU 1 outputs the address whose upper bits are masked to the other input terminal of the address adder 5 via the address bus 8. The address adder 5 adds the address added by the code converter 4 and the address added by the CPU 1, and outputs the addition result as a read address of the memory 7. The memory 7 reads the character pattern data corresponding to the character code according to the address and outputs it to the CPU 1 via the data bus 2.

With such a configuration, the CPU 1 can receive the attribute data of the character pattern and the character pattern data only by the software for inputting the character code.

This is effective when drawing characters on a bitmap display, but especially in Japanese (Kanji) processing, which requires not only alphanumeric characters and symbols but also a very large number of character types.

Also, when a hard copy of a screen image composed only of character codes is taken, it is necessary to read out the font pattern of each character in order to compose the image, but in this case also the address is calculated by software processing. The processing time can be much shortened.

<Effect of Device> As described in detail above, according to the present invention, it is possible to provide a display control device capable of automatically generating a character pattern in a short time based on a general-purpose character code. .

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, FIGS. 2 and 3 are explanatory views of a pattern storage memory in FIG. 1, and FIGS. 4 (a) and 4 (b) are character patterns of a memory area. It is a figure showing the storing method. 1 ... CPU, 2 ... Data bus 3 ... Code register, 4 ... Code converter 5 ... Address adder 6 ... Attribute register 7 ... Pattern storage memory 8 ... Address bus

Claims (1)

[Scope of utility model registration request] 1. A memory in which character patterns of a plurality of items having different dot configurations are arranged and stored so as to have consecutive addresses for each item, a code register for designating a character code to be read, and a code register from the code register. A code converter for converting a read character code into an address of the memory in which a character pattern is stored and converting into attribute data including a dot configuration; an attribute register for latching attribute data output from the code converter; An address adder that adds the address output from the CPU and the address output from the code converter based on the attribute data output from the attribute register to generate the read address of the memory. Display system Apparatus.