JPH03260871A - Logic simulator - Google Patents

Abstract

PURPOSE:To increase the processing speed of a logic simulator compared with a software simulator and to obtain the logic simulator at the hardware costs of a general-purpose computer and a logic arithmetic part by adding a logic arithmetic part for logic simulation to the general-purpose computer containing a CPU and a memory. CONSTITUTION:A general-purpose computer 1 containing a CPU 2 and a mem ory 3 is prepared together with a logic arithmetic part 4 connected to the com puter 1. The computer 1 carries out the processing except the logic arithmetic in the logic simulation and the logic arithmetic that is unable to be processed at the part 4. The part 4 is connected to the computer 1 and carries out the logic arithmetic for simulation under the control of the computer 1. The com puter 1 writes the logic arithmetic input into an input register and reads the logic arithmetic output out of a result register. If the computing speed of a logic arithmetic circuit is satisfactorily high, the relevant flow is executed with two instructions of the computer 1. Thus the logic simulation is carried out at a low cost and at a high speed.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a logic simulator, particularly a logic simulator that improves the execution speed of logic simulations by adding a logic operation section to a general-purpose computer to perform logic operations for logic simulations. Regarding.

[Technological environment]

With the recent development of IC technology, the design of large-scale logic circuits has become very common, and the design is often performed while verifying the logic using logic simulation, and it has become important to perform logic simulation at high speed. There is.

[Conventional technology]

Conventional logic simulators are general-purpose computers, and there are two types: software logic simulators that perform logic simulations using software, and hardware logic simulators that perform logic simulations using dedicated hardware.

[Problem to be solved by the invention]

Among the conventional logic simulators mentioned above, software logic simulators can be used on general-purpose computers and have low hardware costs but are slow, while hardware logic simulators are fast but require specialized hardware. The disadvantage was that it was costly.

[Means to solve the problem]

The configuration of the logic simulator of the present invention includes a general-purpose computer including a CPU and a memory, and a logic operation section that executes logic simulation logic operations under the control of the CPU.

〔Example〕

Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. The logic simulator shown in FIG. 1 includes a general-purpose computer 1 including a CPU 2 and a memory 3, and a logic operation section 4 connected to the general-purpose computer 1.

The general-purpose computer 1 executes processes other than logical operations in the logical simulation and logical operations that cannot be processed by the logical operation section 4 among the logical operations. The logic operation unit is connected to the general-purpose computer 1 and executes simulation logic operations under its control.

FIG. 2 is an example of the logic operation section in FIG. 1. It is connected to a general-purpose computer 1 via a control bus a, an address bus b, and a data bus C. Address decoder 5 is connected to control bus a and address bus b, and outputs input register write signal d and output multiplexer selection read signal e.

Input register 6 reads data on data bus C in response to input register write signal d, and outputs logic operation input f to logic operation circuits 7.1 to 7.n.

The logic operation circuits 7, 1 to n are composed of logic circuits, input the logic operation power f, and perform the respective logic operations, AND,
OR, NOT, etc. are output to logical operation outputs g, 1 to n.

The output multiplexer 8 selects the logic operation outputs g, 1 to n based on the output multiplexer selection read signal e, and outputs them to the data bus C.

FIG. 3 shows an example of the processing flow of a logical operation performed by the general-purpose computer 1 in FIG. 1 by controlling the logical operation section 4. The general-purpose computer 1 writes a logical operation input to an input register (step 10), Step 11 of reading the logic operation output from the result register, logic operation circuit 7
．． If the processing speeds 1 to n are sufficiently high, the above flow can be executed by two instructions of a general-purpose computer.

〔Effect of the invention〕

The logic simulator of the present invention has a configuration in which a logic operation section for logic simulation is added to a general-purpose computer having a CPU and memory, so it is faster than a software simulator and can be realized with the hardware cost of a general-purpose computer and logic operation section. It is cheaper than a software simulator, and has the advantage that it can be used as a general-purpose computer when not used for logic simulation.

register write signal, e...output multiplexer selection read signal, f...logical operation output, g, 1~
n: Logical operation outputs 1 to n, h: Output multiplexer output signal.

Claims (1)

[Claims] A logic simulator comprising: a general-purpose computer including a CPU and a memory; and a logic operation section that executes logic operations for logic simulation under control from the CPU.