JPH0922343A - Arithmetic unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an arithmetic unit with which a function operation is performed at high speed by making a function table programmable and plural function operations can be dealt with by rewriting the contents of the function table. SOLUTION: The arithmetic unit with which the function operation is performed while using a look-up table, is composed of an instruction/operation executing part 1 for performing the function operation, argument register 2 for storing arguments, programmable arithmetic part 3, arithmetic part program control part 4 for that, programmable function table 5, function table program control part 6 for that, programmable arithmetic part 7, arithmetic part program control part 8 for that, and solution register 9 for storing solutions. The function table or the like to be frequently used is previously programmed to the function table 5 by the instruction/operation executing part 1 and besides, operation expressions to be frequently used are programmed to the arithmetic parts 3 and 7 as well.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an arithmetic unit technique using a look-up table, and more particularly to a technique effective when applied to an arithmetic unit suitable for realizing high-speed arithmetic operation and improvement in versatility.

[0002]

2. Description of the Related Art For example, according to a study by the inventor, a method of using a lookup table can be considered as one of the methods for performing high speed calculation. In an arithmetic device using such a method, it is assumed that this lookup table is assigned to a memory in a general-purpose manner and is processed by software, or that arithmetic is performed by hardware having a dedicated function table that cannot be changed. Conceivable.

[0003]

However, in the arithmetic unit as described above, for example, when processing is performed by software, the table is written in a general-purpose memory, so that the processing for searching the table by the search key or the argument is not performed. It is necessary to use software, and it is considered that the processing speed will be limited.

Further, in the method having a dedicated function table that cannot be changed, only a specific function written in the table can be processed at high speed, and it is necessary to increase the number of tables and the capacity in order to increase the number of functions. Conceivable.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above-mentioned problems caused by the operation method using a lookup table, to make the function table programmable, thereby to perform the function operation at high speed, and rewrite the contents of the function table. Accordingly, it is an object of the present invention to provide an arithmetic unit capable of supporting a plurality of function operations.

[0006]

The arithmetic unit of the present invention is applied to an arithmetic unit for performing a function operation using a look-up table, and is dedicated to performing a function operation using this look-up table. An instruction that has an instruction, executes a function operation on input data by issuing this dedicated instruction, and outputs the operation result as output data.
It has an operation execution means and at least one or more dedicated function tables in which data necessary for function operation can be pre-programmed.

More preferably, data such as an arithmetic expression required for the function operation is previously stored between the register as the storage means for the input data and the function table, and between the function table and the register as the storage means for the output data. An arithmetic unit as a programmable arithmetic means is provided.

[0008]

According to the arithmetic unit described above, by providing a programmable function table as a look-up table, a function operation using this function table is performed at a high speed, and the contents of the function table are rewritten to obtain a plurality of functions. It can correspond to a calculation.

Further, when a programmable operation unit is provided between the input data register and the function table and between the function table and the output data register, the operation processing using the function table has versatility. Can be made.

As a result, it is possible to improve the high speed operation and the versatility of the operation in the operation device, and the present invention can be favorably applied to a central processing unit of a system device such as a personal computer or a workstation. .

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram showing an arithmetic unit according to an embodiment of the present invention, and FIG. 2 is an explanatory diagram showing a programmable function table and an example of data programmed in an arithmetic unit in the arithmetic unit of the present embodiment. 3 is a block diagram showing a system unit including the arithmetic unit of this embodiment.

First, the configuration of the arithmetic unit of this embodiment will be described with reference to FIG.

The arithmetic unit of this embodiment is, for example, an arithmetic unit for performing a functional operation using a look-up table.
An instruction / operation execution unit 1 (instruction / operation execution means) for performing a function operation, an argument register 2 for storing arguments, a programmable operation unit 3 and its operation unit program control unit 4, and a programmable function table 5. The function table program control unit 6, the programmable operation unit 7, the operation unit program control unit 8 and the solution register 9 for storing the solution are included.

The instruction / arithmetic execution unit 1 has a dedicated instruction set for performing a function operation using a look-up table, and by issuing this instruction set, the input data from the argument register 2 can be programmed. Arithmetic unit 3,7
Also, control is performed to execute the function operation programmed in the operation units 3 and 7 and the function table 5 through the programmable function table 5, and to output the operation result to the solution register 9 as output data. .

Data such as an arithmetic expression required for function operation is programmed in the programmable arithmetic unit 3 in advance through the arithmetic unit program control unit 4, and for example, x '.
= ROUND (x / 1.40625) is stored. This ROUND (x / 1.40625) is an operation for rounding (x / 1.40625),
Further, x is given by an angle [°]. And
As shown in FIG. 2 (a), this x '= ROUND (x / 1.
40625) necessary data, that is, argument register 2
The argument data x from is input, and the output data x ′ of this operation result is output to the programmable function table 5.

The programmable function table 5 is pre-programmed with data necessary for function calculation through the function table program control unit 6, for example y '.
= Sinx 'and the data obtained by this operation are stored in a table format as shown in FIG. 2 (b). The operation output data x ′ from the programmable operation unit 3 is input to the data necessary for the operation of y ′ = sinx ′, and the output data y ′ of this operation result is output to the programmable operation unit 7. It has become so.

Data such as an arithmetic expression required for function arithmetic is programmed in the programmable arithmetic unit 7 in advance through the arithmetic unit program control unit 8, for example, y =
An arithmetic expression of 0.0078125 × y ′ is stored. Then, as shown in FIG. 2C, this y = 0.007812
The necessary data for 5 × y ′, that is, the output data y ′ from the programmable function table 5, is input, and the output data y of this operation result is output to the solution register 9.

Next, regarding the operation of this embodiment, the outline of the arithmetic processing by this arithmetic unit will be described.

That is, in the present embodiment, the instruction / operation execution unit 1 having a dedicated instruction set for performing an operation using a lookup table is a function table programmable via the function table program control unit 6. Program frequently used function tables for 5. After the program is completed, the solution of the programmed function can be immediately obtained in the solution register 9 by setting the argument in the argument register 2.

Further, the programmable function table 5 can be provided with versatility by having the programmable operation units 3 and 7 in the operation device as in the present embodiment. For example, when the upper limit of the size of the programmable function table 5 is fixed, rounding processing of arguments or solutions, or when obtaining a solution of another linear function without changing the function table is performed. This can be easily realized by programming necessary arithmetic operations in the programmable arithmetic units 3 and 7 via the local program control units 4 and 8.

Further, when a frequently used function changes, the programmable function table 5 and programmable operation units 3 and 7 are programmed again with the function operation formula and necessary data to immediately You can get the solution of the new function.

Next, for example, when the number of columns of the programmable function table 5 is 8 bits (256 columns) and the data resolution is 8 bits (256 mesh), y
A specific example of the calculation of = sinx will be described based on the data example of FIG.

In advance, x '=
The operation expression of ROUND (x / 1.40625) is programmed into the programmable operation unit 7 by the operation expression of y = 0.0078125 × y ′, and further the operation of y ′ = sinx ′ is executed into the programmable function table 5. A table in a table format as shown in FIG. 2 (b) for storing the data obtained by this calculation is programmed together with the formula.

First, the argument data x from the argument register 2 is input to the programmable arithmetic unit 3, and the arithmetic unit 3 executes the arithmetic operation of x '= ROUND (x / 1.40625). This operation rounds the argument x of the argument register 2 and returns the value of 25 in the programmable function table 5.
This is an operation for performing a distribution process in 6 columns. The output data x ′ of this calculation result is output to the programmable function table 5.

Further, a programmable function table 5
In, the output data x ′ from the programmable operation unit 3 is used to execute the operation y ′ = sinx ′. This calculation is a calculation for obtaining a sin curve. The output data y ′ of this operation result is output to the programmable operation unit 7.

Then, the programmable operation unit 7 executes the operation of y = 0.0078125 × y ′ using the output data y ′ from the programmable function table 5. This operation is an operation of multiplying the output of the programmable function table 5 by the mesh width. The output data y of this operation result is output to the solution register 9.

As a result, when x in the table of FIG. 2 (a) is given as an argument of the argument register 2, the operation result x'by the rounding process of the programmable operation unit 3 is output and its output data x '. Is given to x'of the function table 5 in the table of FIG. 2 (b), the output of y'is obtained, and the processing result of multiplying the output of y'by the mesh width is shown in the table of FIG. 2 (c). Then, y = sinx can be calculated by this processing.

Therefore, according to the arithmetic unit of this embodiment, the programmable arithmetic unit 3, the function table 5 and the arithmetic unit 7 are provided in addition to the instruction / arithmetic execution unit 1 for performing the functional arithmetic. It is possible to perform a function operation using the function table 5 at a high speed and to cope with a plurality of function operations by rewriting the contents of the function table 5. Further, the operation units 3 and 7 perform an operation using the function table 5. The processing can be made versatile.

Further, in the arithmetic unit of the present embodiment, as shown in FIG.
Argument register 10 indicated by a broken line, programmable arithmetic unit 11 and its arithmetic unit program control unit 12, programmable function table 13 and its function table program control unit 14, programmable arithmetic unit 15 and its arithmetic unit program control When the section 16 and the solution register 17 are provided, and when more than one set of arithmetic functions is provided, different operations can be executed for each system, so that more function operations can be performed at high speed. it can.

Further, the arithmetic unit as in this embodiment is located inside the CPU 18 of a system unit such as a personal computer or a workstation as shown in FIG. In this case, the CPU 18 has the conventional configuration including the instruction execution mechanism / arithmetic mechanism 19, the arithmetic unit 20 having the above configuration, the general-purpose register 21, and the primary cache 22.
The functions characteristic of the present invention are added to the arithmetic unit 20 to enable support. Further, a secondary cache 23, a memory 24, an input device 25 such as a keyboard and a mouse, an output device 26 such as a CRT and a printer, and an input / output device 27 such as an HDD are connected to the outside of the CPU 18, and are configured as a system device. It is possible to further improve the versatility of and the processing performance of calculation.

It is needless to say that the present invention is not limited to the above-mentioned embodiment, and various modifications can be made without departing from the scope of the invention. For example, in the above-described embodiment, the function calculation of y = sinx has been described as an example, but other function calculations such as differentiation / integration and exponent / logarithm can be widely applied.

[0033]

According to the present invention, a programmable function table is provided, the function operation can be performed at high speed by using this function table, and a plurality of function operations can be performed by rewriting the contents of the function table. can do. Further, when the programmable arithmetic unit is provided, it becomes possible to give versatility to the arithmetic processing using the function table.

As a result, it becomes possible to improve the high-speed operation and the versatility of the operation in the operation device which performs the function operation using the look-up table. For example, the central processing of the system device such as a personal computer or a workstation is possible. By using it in the apparatus, it becomes possible to further improve the processing performance.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an arithmetic unit according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a programmable function table and an example of data programmed in a calculation unit in the calculation device of the present embodiment.

FIG. 3 is a configuration diagram showing a system unit including the arithmetic unit of the present embodiment.

[Explanation of symbols]

1 ... Instruction / arithmetic execution unit (instruction / arithmetic execution means), 2, 1
0 ... Argument register, 3, 7, 11, 15 ... Programmable operation unit, 4, 8, 12, 16 ... Operation unit program control unit, 5, 13 ... Programmable function table, 6, 14 ... Function table program Control section, 9, 17 ... Solution register.

Claims (1)

[Claims] 1. An arithmetic unit for performing a functional operation using a look-up table, having a dedicated instruction for performing a functional operation using the look-up table, and issuing the dedicated instruction to input data. An instruction to execute a function operation and output the operation result as output data
Connected to the operation executing means and this instruction / operation executing means,
An arithmetic unit, comprising: at least one or more dedicated function table in which data necessary for the function operation can be pre-programmed.