JPH09185489A - Device and method for numerical operation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simultaneously execute rounding and saturating operations in the case of executing a procedure for storing data into a memory by connecting a rounding/saturation processing circuit for performing the rounding/saturating operation between the output terminal of register and the input terminal of memory. SOLUTION: First of all, processing information is stored from a program memory 2 into a register 8 according to the contents of program counter 7 and this processing information and the contents of mode register 9 specifying how to modify the relevant processing information are inputted to a decoder 3 as a converting circuit. Thus, series of desired numerical operations are executed while controlling an input switching part 11, register 10 and numerical operation circuit 4. In this case, when processing is executed for storing the numerical operated result or the like into a memory 6, the output signal from the register 10 is stored through the rounding/saturating operation at a rounding/saturation processing circuit 5 into the memory 6. When executing the procedure of storage into the memory 6, the contents in the mode register 9 are referred to.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a numerical operation device and a numerical operation method, and is suitable for application to, for example, a device that decodes by a software program instruction and executes a numerical operation.

[0002]

2. Description of the Related Art Conventionally, a procedure-driven digital circuit for the purpose of numerical calculation has a block in which a numerical calculation circuit and a circuit for temporarily storing an input and an output to the numerical calculation circuit are grouped together with a numerical value. Generally, a main storage device having a finite word length for the purpose of storing intermediate results and end results of operations and buffering is connected to a bus.

At this time, when the intermediate result of the numerical operation is stored in the main storage device, or when the result of the numerical calculation is stored in the main storage device for the purpose of outputting to the outside, the word of the result of the numerical calculation is used. In many cases, the lower bit side of the length is rounded (that is, rounded off) and then the result is appropriately saturated to reflect that it is a finite word length. This is because the word length of the result of the numerical operation is usually longer than the word length of the main memory.

[0004]

As described above, in many conventional procedure-driven digital circuits for the purpose of numerical operation, it is possible to perform a procedure in which the numerical operation itself and the rounding / saturating operation are integrated. Seen and common.

However, in a procedure-driven digital circuit intended for numerical calculation, how to finish execution of a plurality of given procedures in a short time is an important issue.
Here, in order to perform the rounding / saturation operation, it is necessary to perform processing of writing to the register according to each instruction signal, then reading and writing to the memory, which is a problem that it takes time.

The present invention has been made in consideration of the above points, and the procedure of rounding / saturating operation prior to storage in the main storage means and the storage itself in the main storage means that occurs consecutively thereto are integrated. The present invention intends to propose a numerical operation device and a numerical operation method that can be followed.

[0007]

In order to solve such a problem, according to the present invention, there are provided a register for temporarily holding data, and a numerical operation means for performing a predetermined operation process on data input from the register. , A main storage means for holding a plurality of finite word length data, a bus interconnecting the register, the numerical operation means and the main storage means with each other, an output from the numerical operation means and an output from the register to the main storage means In this case, rounding / saturation processing means for performing rounding processing and / or saturation processing and control means for controlling the register, the numerical operation means, the main storage means and the rounding / saturation processing means are provided.

Further, according to the present invention, in a numerical operation method in which a software program decodes and executes a predetermined process, a predetermined register is read out, and a rounding process and / or a saturation process is performed according to the presence / absence of a flag to perform a predetermined process. Make sure to write to the storage means.

A register for temporarily holding data, a numerical operation means for performing a predetermined operation process on the data input from the register, a main storage means for holding a plurality of finite word length data, and a register. , A bus interconnecting the numerical calculation means and the main storage means with each other, and when the output from the numerical calculation means and the output from the register are led to the main storage means,
By providing the rounding / saturating processing means for performing the rounding processing and / or the saturation processing and the control means for controlling the register, the numerical operation means, the main storage means and the rounding / saturation processing means respectively, the data is stored in the main storage means prior to the storage. It is possible to realize a numerical operation device capable of integrally processing the rounding / saturating operation and the storage itself in the main storage means that occurs successively in the processing.

Further, according to the present invention, in a numerical operation method in which a software program decodes and executes a predetermined process, a predetermined register is read out, and a rounding process and / or a saturation process is performed depending on the presence or absence of a flag to perform a predetermined process. By writing in the storage means, the rounding / saturating operation processing prior to the storage in the main storage means and the storage itself in the main storage means that occurs consecutively to the processing can be integrally processed. Can be realized.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows the overall configuration of a numerical operation device 1 according to the present invention. The numerical operation device 1 includes a program memory 2, a decoder 3, a numerical operation circuit 4, a rounding / saturation processing circuit 5, a memory 6, and a plurality of registers 7, 8, 9, 1.
It is composed of 0 and the like.

The program memory 2 is the numerical operation device 1
A storage device for storing processing information for driving the
It is connected to a program counter 7 which is a register for storing an address for designating which processing information is read from the program memory 2. Further, the program memory 2 is connected to a register 8, which is a register for storing processing information read from a specific location of the program counter 7 designated by the contents of the program counter 7. .

The mode register 9 is connected to the decoder 3 because it is a register that holds information that defines how to modify the processing information stored in the register 8. The decoder 3 includes a register 8 and a mode register 9
Is a circuit that converts the contents held in each of the registers 10, the numerical operation circuit 4, the input switching unit 11, and the rounding / saturation processing circuit 5 into signals that are actually necessary for control, and therefore is connected to each. ing.

The register 10 is a register for holding the input to the numerical operation circuit 4 and the output of the numerical operation circuit 4, and the input switching unit 11 receives the output of the numerical operation circuit 4 as the input of the register 10. , Or the output from the memory 6 as an input.

The rounding / saturation processing circuit 5 is a circuit for performing rounding and saturation operations on the output from the register 10.
The output signal is connected to be sent to the memory 6. Incidentally, the memory 6 is a storage device used for buffering for the purpose of intermediate result of numerical operation and input / output with an external circuit (not shown). Incidentally, the content itself of the program counter 7 is also controlled by the processing information stored in the program memory 2 and a circuit (not shown) which generates a control signal for the program counter 7 from the processing information.

Next, FIG. 2 shows a flow chart showing a rounding / saturation processing procedure of the numerical operation device 1. Step SP1
Then, the numerical operation unit 1 starts the processing and reads the register 10 at step SP2. Then move to step SP3,
Here, it is determined whether or not the flag is set. When a positive result is obtained in this determination, the process proceeds to step SP4, the rounding / saturation processing circuit 5 performs rounding / saturation processing, the process proceeds to step SP5, and is written in the memory 6. On the other hand, when a negative result is obtained in the determination in step SP3, the process directly goes to step SP5, the writing to the memory 6 is performed, and the processing ends in step SP6.

In the above configuration, first, processing information is stored in the register 8 from the program memory 2 in accordance with the contents of the program counter 7, and this processing information and a mode register for defining how to modify the processing information are stored. 9
By inputting the contents of the above into the decoder 3 which is a conversion circuit, the input switching unit 11, the register 10 and the numerical operation circuit 4 are controlled, and a desired series of numerical operations is executed.

At this time, when the processing for storing the numerical calculation result in the memory 6 is executed, the output signal from the register 10 is stored in the memory 6 through the rounding / saturation operation in the rounding / saturation processing circuit 5. It When the storage procedure in the memory 6 is executed, the contents of the mode register 9 are referred to.

That is, the output signal from the register 10 is stored in the memory 6 according to the contents held in the mode register 9.
The rounding / saturation processing circuit 5 is controlled in the following cases in the storing process to That is, when executing the procedure of the storing operation of the rounding / saturation processing circuit 5, "no rounding / saturation operation is performed", "rounding operation only", "saturation operation only", "rounding / saturation" The operations are performed together ".

The mode register 9 is for designating ON / OFF of the rounding operation and the saturation operation. Therefore, the necessary rounding / saturation control can be realized by a single procedure. Further, since the rounding / saturating operation can be executed at the same time when the procedure for storing the data in the memory 6 is executed, it is more convenient than the conventional one.

According to the above configuration, the rounding / saturation processing circuit 5 for performing the rounding / saturation operation is connected between the output end of the register 10 and the input end of the memory 6, whereby the memory 6
The rounding / saturating operation can be performed simultaneously when performing the data storage procedure to. That is, with software processing, processing that has conventionally required three or more steps can be performed by one step, which leads to simplification of processing.
Further, the contents of the mode register 9 enable each of the above-mentioned four types of control, so that necessary rounding / saturation control can be realized by a single procedure without providing four independent procedures corresponding to each. .

Furthermore, since the processing for sending the output signal from the register 10 to the memory 6 also has the rounding / saturating operation, the number of procedures required for writing the numerical data into the memory 6 is reduced. be able to. Further, when the program memory is provided on the chip of the semiconductor device, the space required for the program memory can be saved as compared with the conventional case, which leads to the miniaturization of the chip of the semiconductor device.

In the above-mentioned embodiment, the description is made of the one which is decoded and executed by the software program instruction, but the present invention is not limited to this, and it is also suitable to be applied to the one which is executed by hardware.

[0025]

As described above, according to the present invention, a register for temporarily holding data, a numerical operation means for performing a predetermined operation process on data input from the register, and a plurality of finite words. Main storage means for holding long data,
A bus that interconnects a register, a numerical operation unit, and a main storage unit, and a rounding / saturation process that applies a rounding process and / or a saturation process when the output from the numerical operation unit and the output from the register are introduced to the main storage unit. By providing the processing means and the control means for controlling the register, the numerical operation means, the main storage means and the rounding / saturation processing means respectively, the rounding / saturation operation processing prior to the storage in the main storage means and the processing concerned It is possible to realize a numerical operation device capable of integrally performing the storage itself in the main storage means that occurs successively and reducing the processing when writing the numerical data into the main storage means.

Further, in a numerical operation method in which a software program decodes and executes a predetermined process, a predetermined register is read, a rounding process and / or a saturation process is performed depending on the presence or absence of a flag, and the result is written in a predetermined storage means. By doing so, the rounding /
It is possible to realize a numerical operation method capable of reducing the processing when writing the numerical data into the main storage means by integrally processing the processing of the saturation operation and the storage itself in the main storage means that occurs successively to the processing.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an overall configuration of a numerical operation device with a rounding / saturating operation in an embodiment of the present invention.

FIG. 2 is a flow chart showing a rounding / saturation procedure according to the present invention.

[Explanation of symbols]

1 ... Numerical value calculation device, 2 ... Program memory, 3 ...
Decoder, 4 ... Numerical value calculation circuit, 5 ... Rounding / saturation processing circuit, 6 ... Memory, 7 ... Program counter, 8,
10 ... Register, 9 ... Mode register, 11 ... Input switching section.

Claims (5)

[Claims] 1. A register for temporarily holding data, a numerical operation means for performing a predetermined operation process on the data input from the register, and a main memory for holding a plurality of finite word length data. Means, a bus interconnecting the registers, the numerical operation means, and the main storage means with each other, a rounding process and / or a rounding process when the output from the numerical operation means and the output from the register are led to the main storage means. A numerical operation device comprising rounding / saturation processing means for performing saturation processing, and control means for controlling the register, the numerical operation means, the main memory means and the rounding / saturation processing means, respectively. 2. The numerical operation device according to claim 1, wherein the rounding / saturation processing means rounds off data at a predetermined position as rounding processing. 3. A numerical operation method for decoding by a software program to execute a predetermined process, reading a predetermined register, rounding and / or saturating depending on the presence or absence of a flag, and storing it in a predetermined storage means. Numerical calculation method characterized by writing. 4. The numerical operation method according to claim 3, wherein the rounding process and / or the saturation process is performed only when the flag is set. 5. The numerical operation method according to claim 4, wherein the rounding process and the saturation process can be arbitrarily selected.