JPS59184392A - Address calculation for font memory - 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] The present invention relates to a font memory address calculation method,
In particular, the present invention relates to a method of calculating an address for a font memory in which characters corresponding to Kanji codes such as the J-Technology-S Kanji code are stored.

FIG. 1 shows a general example of a font memory address calculation method.

1 is a kanji code conversion means for converting a kanji code JO such as the J-K S kanji code into a continuous code OOK; 2 is an address specifying means for specifying an address signal F4 to be added to the font memory 3 based on the continuous code CC; 3 is the font memory.

The Japanese Industrial Standards (JIS) defines graphic characters used to express normal Japanese sentences based on predetermined codes.

This code specifies special characters, numbers,
These are Roman letters, hiragana, katakana, Greek letters, Russian letters, and kanji, and most of them are kanji. As shown in Figure 2, this code C (hereinafter referred to as JIS Kanji code) has a 2-byte structure consisting of the upper 1 byte and the lower 1 byte. One category area up to ``r71!17K (hexadecimal expression)'' is the definition area (the shaded area in FIG. 2). Other areas are undefined areas. This 51CN J Engineering S Kanji code is not a completely continuous code system, so if this code is used as it is, subsequent processing will not be efficient. Therefore, this kanji code JO is the kanji code conversion means l
By j rib□5□0e7-1. . . Engineering, □
6゜In addition to this J Engineering S Kanji code system, 2
There are some kanji code systems that specify that the most significant bit of each byte in the byte code is always set to "1," but even if it eventually becomes K, not all of the 2 bytes) = + - code are defined as the defined area. There is no complete continuous chord system.

Next, FIG. 3 shows an overall conceptual diagram of the font memory 3. In this way, graphic characters corresponding to the Kanji codes are stored in each storage area in the 1-font memory 3 in a form corresponding to the actual shape. That is, in the storage in the font memory 3, one character (unit block in FIG. 3) is composed of, for example, 16x16 bits, 24x24 pits, or 32x32 bits, and for this reason, one character is usually stored across multiple addresses. A method is being adopted.

Therefore, in general, when reading out various graphic characters stored across a plurality of addresses in this way, an address signal indicating the first address of each graphic character in the font memory 3 is sent, for example, based on the continuous code OO. An address signal FA to be added to the font memory 3 is formed based on the calculated address signal and information KY indicating the storage capacity occupied by one graphic character. The address designating means 21C converts the continuous code 00 into an address signal FA.

Now, as a method for calculating the start address in such an addressing method, the following two methods have been conventionally used.

(1) A method of calculating using an equivalent logic operation circuit corresponding to the relationship between an input code (such as a continuous code) and address information corresponding to the first address to be output.

(2) A memory having at least separate storage areas corresponding to all possible patterns of the input code (continuous code, etc.) is adopted, and all address information corresponding to the first address is stored in the storage area. How to do it.

However, the method (1) above is an address calculation method that lacks general versatility because it uses a dedicated arithmetic unit that corresponds to the relational expression between the input code and the output code, and the above relational expression is generally complex. This method requires a complicated arithmetic unit, which has disadvantages such as an increase in calculation time.

In addition, the method (2) above has the disadvantage that the memory requires separate storage areas corresponding to all the patterns that the input code can take, requiring a large amount of storage area.

The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to provide a font memory address respecting method that eliminates the above-mentioned drawbacks by using two memories of small storage capacity and a simple adder.

That is, the present invention divides the entire storage area of a font memory into a plurality of block areas each having a storage area corresponding to a plurality of graphic characters, and then calculates an address signal corresponding to the first address of each graphic character in the font memory. More specifically, it attempts to select any one within the block area based on the upper bit part of the input code.
storage of a first memory in which address information corresponding to two addresses is stored, respectively; when one content is read out, a relative displacement address from the reference address in the block area is calculated based on the lower bit part of the input code; After reading out the storage contents of the second memory in which address information corresponding to the relative address indicated is read out, the address information read out from the first and second memories is added to read out the contents of the respective graphic characters. K is configured to calculate an address signal corresponding to the first address. Based on the address signal thus obtained and information indicating the storage capacity occupied by one graphic character, an address signal finally added to the font memory is formed. This allows the total storage capacity of the two memories to be at least equivalent to the sum of the number of patterns that the upper bits of the input code can take and the number of patterns that the lower bit part of the input code can take.

1 Hereinafter, the font memory address calculation method according to the present invention will be described in detail with reference to the embodiments shown in the accompanying drawings.

First, the present invention will be explained in detail with reference to FIG.

As shown in Figure 3 above, the font memory 3 is
One character is stored across multiple addresses. In such a font memory 3, the address signal applied when reading various graphic characters is calculated based on the address signal indicating the starting address of the graphic character and the information KY indicating the storage capacity occupied by one graphic character. It is also as mentioned above.

In the present invention, the entire storage area of the font memory 3 is divided into a plurality of blocks, and each of the divided block areas is made to correspond to a storage area for a plurality of graphic characters.

For example, FIG. 4 shows an example in which the shaded area in FIG. 3 is one block area. In other words, 1 in this case
The block area contains graphic characters "A", "B", "C", and "D".

In FIG. 4, it is assumed that the sections corresponding to the shaded areas are unit address areas of 1 byte, 2 bytes, 4 bytes, etc., for example. Therefore, the single character storage capacity K of these graphic characters
Y is a set of a plurality of unit address areas. In this case, α is the absolute address of the beginning in the storage area corresponding to the graphic character "A", and similarly, the absolute addresses of the beginnings of the graphic characters rBJ, "O", and "D" are α+β8. α+β1. Let α+β3.

In other words, the start address of each graphic character in a certain block area is any one address (
By setting a reference address (hereinafter referred to as a reference address) and finding a displacement address (hereinafter referred to as a relative address) indicating the number of addresses from the reference address, the calculation can be made by adding this reference address and the relative address. . In FIG. 4, the reference address is the starting address α in the block area, and the relative addresses are β1, . β2. It was set as β3.

A final address signal for reading one graphic character is formed based on the head address signal of the graphic character calculated in this manner and information KY indicating the storage capacity occupied by one graphic character. One graphic character is sequentially read out for each unit address area based on the formed address signal.

FIG. 5 shows an embodiment of the font memory address calculation method according to the present invention.

In FIG. 5, it is assumed that the input code CO is a continuous code of 2 bytes in this embodiment.

The input register IO has a 2-byte register configuration corresponding to the code aa, and uses the upper byte σ0 of the code 00 as an address signal to input the reference address storage memory 20.
The lower byte L○ is outputted to the relative address storage memory 30 as an address signal. Since the input code is a continuous code, unnecessary empty storage areas in the memories 20 and 30 can be eliminated. The reference address storage memory 20 has a storage area corresponding to at least the number of patterns that the upper byte can take, and each storage area has a plurality of block areas that can be indicated by the input upper byte. A reference address (the first address in FIG. 4) is stored respectively. The relative address storage memory 30 has a storage area corresponding to at least the number of possible patterns of the lower one byte, and each storage area stores the relative address corresponding to the inputted lower byte. There is. That is, in this embodiment, the entire storage area of the font memory 3 is divided into the aforementioned plural block areas by the upper byte UOK of the input code OC, and the block area is further divided into areas for different graphic characters by the lower byte LO. It will be done. The adder 40 performs an addition operation using as input the reference address information read from the reference address storage memory 20° and the relative address information read from the relative address storage memory 30, and adds the addition result AA to the reading circuit 50. . As is clear from the above description, the addition result AA obtained in this manner serves as address information indicating the starting address of each graphic character in the font memory 3. The reading circuit 50 inputs the final address signal for reading the graphic character corresponding to the code aa based on the address information AA indicating the first address and the information KY indicating the storage capacity of one graphic character, and outputs the final address signal to the unit address. Each area (see FIG. 4) is formed in sequence and added to the font menu 3 in sequence. After 5K, graphic characters corresponding to the reading circuit 50 are output from the font memory 3. Note that the information KY is usually not a constant value. This is because, for example, even in kanji, there are differences in character size, such as 9 points and 12 points, and the required storage capacity for one character is different. Reading circuit 5
The graphic characters read by 0 are adjusted in character size, print position, etc., and then sent to the imaging buffer 6.
It is input to 0. Imagen.

The buffer 60 is, for example, a line buffer, and outputs the graphic characters temporarily stored in the lines to the printer at predetermined intervals.

Note that in the above-described embodiment, the reference address was the start address of each block area, but the reference address may be any address within each block area as long as it is acceptable for the calculation of the relative address to be somewhat complicated. Of course.

Furthermore, in the above-mentioned embodiment, the input code is 2 bytes, and the code is divided into the upper byte and lower byte for subsequent processing, but various conditions, such as the manner in which blocks are divided into font memory, or the type of input Due to the relationship between the kanji code and the contents of the font memory, etc.
-It is not always possible to divide bytes. In such a case, divide the input code into an upper bit part and a lower bit part using appropriate bits, divide the entire storage area of the font memory into multiple block areas using the upper bit part, and then divide the entire storage area of the font memory into multiple block areas. Each block area may be divided into different graphic and character areas by the following.

In addition, in this embodiment, in order to reduce the storage area of the reference address storage memory and the relative address storage memory, one
Although the input code is a continuous code, the input code applied to the present invention is not limited to the continuous code, but may also be other kanji codes other than the conversion J-K8 kanji code or the J-Ko S kanji code. Of course, the present invention can also be applied to large-scale buttons. The point is that the address information to be stored in the two memories can be appropriately set by considering the relationship between the input code and the contents stored in the font memory and using the method of the present invention described above.

As described above, (1) according to the font memory address calculation method according to the present invention, (1) the storage area of the memory for calculating addresses to the font memory can be significantly reduced with a simple configuration;

(2) Since the calculation is only a simple addition, it is possible to speed up address calculation.

(3) It can be applied to a wide range of kanji code systems by simply changing the memory contents.

and other excellent effects.

[Brief explanation of drawings]

Figure 1 is font memory! Figure 2 is a block diagram showing a general configuration example of the font memory. FIG. 5 is an explanatory diagram illustrating a font memory address calculation method according to the present invention, and is a block diagram showing an embodiment of the present invention. l... Kanji code conversion means, 2... Address designation means, 3... Font memory, lO... Input buffer, 20... Reference address storage memory, 30... Relative address storage memory, 40 ...Adder, 50...Reading circuit, 60...Imaging buffer. Figure 1 Figure 2 Soil height Figure 5

Claims (1)

[Claims] An address signal is added to a font memory in which graphic characters corresponding to a predetermined code are stored across multiple addresses, and an address signal corresponding to the first address of the graphic character indicates the storage capacity occupied by one graphic character. In the font memory address calculation method, the font memory is divided in advance into a plurality of block areas that can be indicated by the upper bit part of the predetermined code, and the block area is calculated based on the upper bit part of the predetermined code. The storage contents of the first memory in which address information corresponding to any one of the addresses is stored are read, and the address information corresponding to any one of the addresses in the partitioned block area is read out based on the lower pit part of the predetermined code. Reading out the stored contents of the 20th memory in which address information corresponding to a relative address indicating a relative displacement from one address is stored, and then adding the address information read from the first and second memories. A font memory address calculation method characterized in that an address signal corresponding to a leading address of each graphic character in the font memory is calculated by performing the following steps.