JPH052472A - Arithmetic unit - Google Patents

Abstract

PURPOSE:To perform the arithmetic operation including the conditional judgment without reducing the processing speed of a DSP by selecting and executing a program necessary for the DSP (digital signal processor) after the decoding of an input command from an input device and the conditional judgment are performed at a CPU side. CONSTITUTION:When each kind of the command is inputted in order to perform the arithmetic processing including the conditional judgment from an input device 1, a CPU 3 sends a holding signal to a DSP 2, stops the action of the DSP 2 once, performs the conditional judgment in accordance with the input command, decodes it, selects the program to be performed for the DSP 2 from a program memory 4, loads to a RAM 5 and sends a program transfer control signal to the program memory 4. The program memory 4 transfers the program selected in accordance with the signal to the RAM 5. After that, when the CPU 3 releases the holding signal, gives the execution command to the DSP 2 and re-starts, the DSP 2 executes the arithmetic processing with the program to load to the RAM 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an arithmetic unit composed of a digital signal processor (hereinafter referred to as DSP) capable of executing arithmetic operations and logical operations at high speed.

[0002]

2. Description of the Related Art Generally, a device such as a measuring instrument has a built-in micro computer so that various calculations and judgments can be made at high speed without connecting a computer to the outside. There are many. Such a micro computer has a ROM for storing programs and data.
(Read-only memory), RAM (random access memory), peripheral I / O, etc. are required.
In order to make the device compact, a one-chip type micro computer in which these are built in one chip is also widely used. By the way, the operation speed of such a microcomputer is generally calculated by an arithmetic logic unit (ALU),
Although it depends on the clock frequency, the size of the bus, etc., the operation speed of the 8-bit to 16-bit microcomputer is about 1 microsecond per instruction. If it is used, the speed can be further increased, but since the entire configuration becomes large and the cost of the device increases, it is difficult to use it for a device in which price is prioritized. Therefore, recently, a digital signal processor (DSP), which is relatively inexpensive and capable of high-speed processing, has been developed and used for arithmetic operations. Such a DSP is internally pipelined and one instruction 0.1μ
16-bit or 32-bit operation can be done in about a second,
From a software standpoint, the configuration is such that not only arithmetic and logical operations but also conditional judgment can be performed.

[0003]

However, in the case of making a conditional judgment by such a DSP, the conditional judgment instruction generally requires a longer execution time than the arithmetic instruction (execution of one arithmetic operation instruction is required. (It takes about 0.5 μs to make a conditional judgment for 0.1 μs), but in the case of executing an arithmetic operation including a program that causes the DSP itself to make a lot of condition judgment, it is rather the purpose of high-speed operation. There was a problem that could not be achieved.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to perform arithmetic operations including condition judgment without reducing the processing speed of DSP. An object of the present invention is to provide an arithmetic unit capable of executing.

[0005]

DISCLOSURE OF THE INVENTION The present invention, which is proposed to achieve the above object, includes an input device for inputting various commands for performing necessary arithmetic processing including condition determination,
A digital signal processor that retrieves a program stored in RAM and executes arithmetic processing, a program memory in which a plurality of arithmetic processing programs to be executed by this digital signal processor are stored, and a command from the input device is decoded. A central processing unit for selecting a necessary arithmetic processing program from the program memory according to the command, storing the program in the RAM, and causing the digital signal processor to execute the selected program. It is composed.

[0006]

According to the arithmetic unit of the present invention, when various commands for performing arithmetic processing including condition judgment are input from the input unit, the CPU sends a hold signal to the DSP to temporarily stop the operation of the DSP. Then, the condition is determined according to the input command, the program to be executed by the DSP is selected from the program memory, loaded into the RAM, and the D
Reboot the SP. The restarted DSP reads the program transferred to the RAM and executes the program. A command is sent from the input device every time the arithmetic processing to be processed is changed.
There is no problem even if the operation of P is stopped, and the judgment of the command condition can be eliminated in the DSP program. For this reason, it is possible to save the time and effort required to determine the presence and type of the command each time the DSP performs the arithmetic processing, so that the time required for the arithmetic processing can be shortened.

[0007]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. Reference numeral 1 is a man-machine interface, such as a keyboard, for a person to send an instruction by a command to an arithmetic unit.
Input device that constitutes a computer, 2 is a digital signal processor (DSP), 3 is a central processing unit (CPU), 4
Is a program memory, and 5 is a RAM in which a program to be executed by the DSP is stored. Here, in the block diagram, a one-chip microcomputer is used as the CPU, but in the case of a multi-chip structure, a memory, a timer, an I / O, etc. may be prepared in the periphery as necessary.
Further, the program memory 4 has a configuration in which programs a to be executed by the DSP are stored in advance.

According to the arithmetic unit of the present invention as described above, when various commands for performing arithmetic processing including condition judgment are input from the input unit 1, the CPU 3 causes the DSP to operate.
2 to send a hold signal to stop the operation of the DSP 2 once, make a condition judgment according to the command input from the input device 1 and decode it, and select a program to be executed by the DSP 2 from the program memory 4; The program transfer control signal is sent to the program memory 4 so as to be loaded into the program memory 4. In the program memory 4, the program selected according to the program transfer control signal (this is referred to as program x) is transferred to the RAM 5. Then C
When the PU3 releases the hold signal and gives an execution command to the DSP2 to restart it, the DSP2 executes arithmetic processing using the program x loaded in the RAM5. In the present invention as described above, since a command is sent from the input device 1 every time the arithmetic processing to be processed is changed, there is no problem even if the operation of the DSP 2 is stopped at this time.
The condition determination process can be eliminated in the program of P2.

FIG. 2 shows D when processing an arithmetic program.
In the flow chart of the conventional example in which the condition is judged by the SP, the commands a to n are sequentially read, the condition judgment is performed, and then the calculation processes a to n are processed. Before processing n of the program, n
It is necessary to judge the condition once. On the contrary,
According to the present invention, as shown in FIG. 3, after the command input from the input device 1 is decoded and the condition is judged on the CPU side, a program necessary for the DSP to select and execute a necessary program is prepared in advance. Since it is selected, it is not necessary to judge the condition, and therefore the same calculation process x can be performed in a shorter time. In practice, the processing as shown in FIG. 2 is repeated not only once, but the condition judgment must be performed for each repetition, so that the calculation time of the present invention has a great effect of reducing the calculation time.

[0010]

According to the present invention, the command input from the input device is decoded on the side of the central processing unit, the condition is determined, the program to be executed by the digital signal processor is selected from the program memory, and the selected program is selected. Is loaded into the RAM and executed by the digital signal processor, the digital signal processor does not need to make a condition judgment, and therefore the arithmetic processing time is remarkably shortened as compared with the case where only the digital signal processor is used. be able to.

[Brief description of drawings]

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

FIG. 2 is a flowchart showing condition judgment by conventional software.

FIG. 3 is a flowchart showing processing by software in the arithmetic unit of the present invention.

[Explanation of symbols]

 1 ... Input device 2 ... Digital signal processor (DSP) 3 ... Central processing unit (CPU) 4 ... Program memory 5 ... RAM

Claims (1)

What is claimed is: 1. An input device for inputting various commands for performing necessary arithmetic processing including condition determination, a digital signal processor for extracting a program stored in a RAM and executing arithmetic processing, and this digital signal processor. A program memory in which a plurality of arithmetic processing programs to be executed by the signal processor are stored, and a command from the input device is decoded to make a condition determination, and a necessary arithmetic processing program is selected from the program memory according to the command. An arithmetic unit having a central arithmetic unit which is stored in the RAM and causes the digital signal processor to execute a selected program.