JPH0343832A - Label retrieving system - Google Patents

Abstract

PURPOSE:To shorten the label retrieving time by collecting the labels having the same capital letters into a block and storing the addresses of the first and final labels of the block. CONSTITUTION:A label retrieving table 10 which shows the first start address of a label having a capital letter and the start address of the final label is used as a standard for each of labels having the same capital letters. When an actual label is received, the capital letter of the label is recognized and the range of the label is obtained based on the capital letter and by reference to the table 10. Based on this range, a label received between the first and final addresses of the same capital letter stored in a label table 1 by a 2-sentence retrieving method is specified. That is, the labels having the same capital letters are collected into a block and the addresses of the first and final labels of the block are stored. As a result, the label retrieving time is shortened.

Description

[Detailed Description of the Invention] [Summary] Regarding a label search method when specifying a relative address using a label, the purpose of this method is to reduce the time required for label search by searching for each label whose initial letter is the same. Prepare a label search table that shows the first starting address of a label with characters and the starting address of the last label, and when an actual label is entered, recognize the initial letter of the label and use the recognized initial letter. Based on the label search table, find the label range for the initial letter, and based on the range, select 2 between the first and last of the same initial letter in the label table.
It is configured to identify the entered label using a minute search method.

[Industrial Field of Application] The present invention relates to a label search method when specifying relative addressing using labels.

[Prior Art] In the assembler language of digital signal processors, etc., when the value of the operand part is defined elsewhere (
When specifying relative addressing), labels are used. For example, in commands such as JUMP ASK, "JUMP" is a command, and "AS
K" is the operand. In this case, the program jumps to the address labeled "ASK."

In order to perform relative addressing using such labels, it is necessary to replace each label with an address value. Therefore, when a label designation instruction is entered in the middle of a program, the program first recognizes what label has been entered. A binary search method is used as a label identification method for this purpose.

The binary search method uses a comparison operation to determine whether the label to be sought is in the upper half or the lower half of all labels, and once either is determined, it is checked again for the determined region to see if it is in the upper half. Use a comparison operation to find out whether it is in half of the range. This comparison operation is repeated until the target label is specified. In order to perform such a binary search, the labels must be stored in the label table in ascending or descending order.

FIG. 4 is a block diagram of a circuit for implementing the conventional method. In the figure, 1 is a label table that stores labels in ascending order or descending order. This label table 1 has a structure as shown in FIG. 5, for example. Diagram AI
, A22. A3. . . . are labels, and the start address of the address where A1 is stored is 0, and the start address of the address where the last label ZZ9 is stored is K.

A register 2 holds the start address M of the area to be searched, and a register 3 holds the final address N of the area to be searched. Of these registers, register 2 initially contains “
0'', but the register 3 initially holds the final address K of the label table.

In the first comparison operation, the sum of the value M held in the register 2 and the value N held in the register 3, 172, is calculated by the arithmetic unit 4.

That is, the arithmetic unit 4 performs an arithmetic operation expressed as (M+N)/2.

The label table 1 is accessed by the output of the arithmetic unit 4, and the label stored at the address indicated by the address is output. On the other hand, register 5 contains the manually entered label value (
Label code data) is retained. A comparator 6 compares the value held in this register 5 with the label data read from the label table l.

If the label value > (M+N)/2, the label is found in the lower half of the table shown in Figure 5, and if the label value is < (M+N)/2, the label is located in the lower half of the table shown in Figure 5.
It can be seen that it is in the upper half of the table shown in the figure. Depending on the output of this comparator 6, either the value of M or N is (
M+N)/2. That is, in the former case, the value N of register 3 remains unchanged, and M of register 2 becomes (M+N
)/2, and in the latter case, the value M in register 2 remains unchanged, and the value N in register 3 is replaced by (M+N)/2. To perform such operations, selectors 7 (selector 1) and 8 (selector 2) are used.

For example, when replacing M in register 2 with (M+N)/2 while leaving the value N in register 3 unchanged, selector 8 selects the output of register 3, and selector 7 selects the output of arithmetic unit 4.
Select the output of When replacing the value N of register 3 with (M+N)/2 while leaving the value M of register 2 unchanged, selector 7 selects the output of register 2, and selector 8 selects the output of arithmetic unit 4.

In this way, when the range to be searched is halved, the above-described sequence is repeated for this halved area to determine whether it is in the upper or lower half of the new area. Thereafter, the same sequence is repeated until the label held in register 5 is specified.

[Problems to be Solved by the Invention] The conventional binary search method requires a lot of time when there are a large number of labels, and especially when a label that is not stored in the label table is specified due to an error or the like. The problem was that it required the longest search time and the desired label could not be found.

The present invention has been made in view of such problems, and an object of the present invention is to provide a label search method that can shorten the time required for label search.

[Means for Solving the Problems] FIG. 1 is a flowchart showing the principle of the system of the present invention. As shown in the figure, the present invention includes a label search table that shows, for each label whose initial letter is the same, the first starting address of the label having the initial letter and the starting address of the last label. (Step 1). Once the actual label is entered, the initial letter of the label is recognized. Step 2). Based on the recognized initial letter, refer to the label search table to find the range of the label with the initial letter. (Step 3), and based on the obtained range, a binary search method is used to identify the label between the first and last of the same initial in the label table (Step 4). There is.

[Operation] Labels with the same initial letter are grouped together into a block, and a label search table is prepared in which the addresses of the first and last labels of the block are stored. As a result, when specifying a manually entered label, it is only necessary to perform a binary search within the same block as the initial letter of the label, and the time required for label search can be significantly shortened.

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

FIG. 2 is a block diagram showing an embodiment of a circuit implementing the method of the present invention. Components that are the same as those in FIG. 4 are designated by the same reference numerals. In the figure, numeral 10 is a label search table that stores the first start address of the label having the same initial letter and the start address of the last label for each label having the same initial letter. The label conversion table 10 has a structure as shown in FIG. 3, for example.

As shown in the figure, the start address of the first label of the labels having each alphabet as the initial letter and the start address of the last label of the labels having the same initial letter are stored in alphabetical order.

For example, in the case of alphabet A, the starting address of the first label is "0" and the starting address of the last label is "3#".The same applies to other alphabets.For this label search The table 10 receives the first letter of the input label stored in the register 5 as an address.

11 is a selector (selector 3) that receives the output of the selector 7 and the output of the label search table 10 and selects one of them; 12 receives the output of the selector 8 and the output of the label search table 10 and selects one of them; This is a selector (selector 4) that selects one of the two.

The outputs of these selectors 11 and 12 are M
The value is stored in registers 2 and 3 that hold the N value.

The outputs of registers 2 and 3 are fed back to selectors 7 and 8, respectively, and are also input to arithmetic unit 4. The output of the arithmetic unit 4 is fed back to the other input of the selector 7.8, and is also entered in the label table 1 as an address. label table 1
The output of is input to one input of comparator 6, and the output of register 5 is input to the other input of comparator 6. and,
Selector 7.8 is controlled in accordance with the output of comparator 6. The operation of the circuit configured as described above will be explained as follows.

First, a label is held in the register 5, and the first letter of the label is entered into the label table 10 as an address. As a result, the first and last addresses of the alphabets having the initial letter are read from the label table 1o. For example, taking the case of FIG. 3 as an example, addresses "0" and "3" are read out. Read M value, N
The values are respectively loaded into registers 2.3. Arithmetic unit 4
calculates (M+N)/2 from read M and N. This calculation result (M+N)/
2 is given to label table 1 as an address.

In this way, the label table 1 is accessed using the output of the arithmetic unit 4, and the label stored at the address indicated by the address is output. On the other hand, the register 5 holds a manually entered label value (label code data). The value held in this register 5 and the label data read from the label table 1 are compared by a comparator 6.

If the label value > (M+N)/2, the label is found to be in the lower half of the table shown in Figure 5, and if the label value is < (M + N)/2, the label is found in the fifth column.
It can be seen that it is in the upper half of the table shown in the figure. Depending on the output of this comparator 6, either the value of M or N is (
M+N)/2. That is, in the former case, the value N of register 3 remains unchanged, and M of register 2 becomes (M+N
)/2, and in the latter case, the value M in register 2 remains unchanged, and the value N in register 3 is replaced by (M+N)/2. To perform such operations, selectors 7 (selector 1) and 8 (selector 2) are used.

For example, when replacing M in register 2 with (M+N)/2 while leaving the value N in register 3 unchanged, selector 8 selects the output of register 3, and selector 7 selects the output of arithmetic unit 4.
Select the output of As a result, the output (M+N)/2 of the selector 7 enters the register 2 via the selector 11, and the output N of the selector 8 enters the register 3 via the selector 12.

The value M of register 2 remains unchanged, and the value N of register 3 is changed to (
When replacing with M+N)/2, the selector 7 selects the output of the register 2, and the selector 8 selects the output of the arithmetic unit 4. As a result, register 3 has selector 1
The output (M+N)/2 of the selector 8 is input to the register 2 via the selector 11, and the output M of the selector 8 is input to the register 2 via the selector 11.
enters.

In this way, when the range to be searched is halved, the sequence described above is repeated for this halved area to determine whether it is in the upper or lower half of the new area. Thereafter, the same sequence is repeated until the label held in register 5 is specified.

In the above description, alphabets are used as the initial letters of the labels stored in the label search table 10, but the present invention is not limited to this. For example, 50 syllabary characters and other character types can be used.

Furthermore, when using the initial letters of these character types for label searches, characters that do not appear at the first address of the label may enter due to programming errors, but according to the present invention, depending on the label, only the label search table can be used. This is convenient because it may be possible to quickly identify flowers that do not have flowers.

[Effects of the Invention] As described in detail above, according to the present invention, labels having the same initial letter are grouped together into a block, and label search is performed in which the addresses of the first and last labels of the block are stored. By preparing a table for identifying an input label, it is only necessary to perform a binary search within the same block as the initial letter of the input label, and the time required for label search can be significantly shortened.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing the principle of the method of the present invention, FIG. 2 is a block diagram showing an embodiment of a circuit implementing the method of the present invention, FIG. 3 is a diagram showing an example of the structure of a label search table, FIG. 4 is a block diagram of the configuration of a circuit that executes the conventional method, and FIG. 5 is a diagram showing an example of the configuration of a label table. In FIG. 2, 1 is a label table, 2.3 is a register, 4 is an arithmetic unit, 5 is a register, 6 is a comparator, 7.8 is a selector, 10 is a label search table, and 11.12 is a selector.

Claims (1)

[Claims] For each label whose initial letter is the same, a label search table is prepared that indicates the first starting address of the label having the initial letter and the starting address of the last label (step 1). ), when the actual label is entered, the initial letter of the label is recognized (step 2), and the range of the label with the initial letter is determined by referring to the label search table based on the recognized initial letter (step 3). ), a label search method characterized in that based on the obtained range, labels that are included between the first and last of the same initial in the label table are identified by a binary search method (step 4). .