Chapter 604 Come, everyone, look at me!

There were also people who didn't know him, mainly comrades who were engaged in radio communications. As for the command vehicle, the technical personnel were mainly from the armored vehicle factory.

"Who is this? Everyone seems to know him, and he looks quite powerful." A comrade quietly asked the person next to him.

"Uh... it's pretty impressive, but I can't tell you who it is. But you're already attending the meeting, so you'll probably know in a little while."

It seems you will know soon, but I still can't tell you now.

Most of the comrades working on radar, when they saw Gao Zhendong come in, immediately knew that today's incident was definitely closely related to high technology, and it was very new, so new that no one had ever seen or even heard of it.

Looking at a set of specially prepared equipment with slightly complicated connections on a table in the conference room, they were even more certain that the weapon the Defense Work Committee would release this time was probably a big one.

After a while, the leaders of the Defense Work Committee and the chief engineer also came. Since Gao Zhendong was doing such a job that had no beginning or end, the leaders had to come.

Firstly, he was very curious about what could have made Gao Zhendong so excited and mobilize so many troops.

Secondly, if there are any problems, he will be there to help Gao Zhendong.

"Comrades, are all here? Let's start the meeting. Comrade Zhendong, where are your goodies? Take them out, hahahaha."

The leader was very direct and didn't have any opening remarks. The main reason was that he didn't know what to say in the opening remarks. He didn't even know what Gao Zhendong was going to come up with, so he couldn't say anything.

However, his words were still very thoughtful. He did not say "the good things you said you were going to bring out", but "your good things". This made people think that this meeting was the idea of ​​the Defense Work Committee. If there were any problems, Gao Zhendong could not be blamed.

Gao Zhendong nodded and said with a smile: "Well, okay. Before I introduce this thing, let's watch me do two calculation experiments."

Computational experiment? This thing can also be used for experiments? Everyone is very curious.

Then they saw Gao Zhendong turn on the conspicuous computer in the conference room.

After the screen lit up, Gao Zhendong entered the command to perform 60 multiplication operations using the DJS-10D body, but did not press Enter. Instead, he turned around and explained what operation he was going to perform.

After listening to his words, everyone at least understood what his first step should be.

"Repeatedly performing 10-digit multiplication operations 8 times? I don't see the point for now."

"Well, and 8-bit integer multiplication doesn't make much sense, so what if I do it 10 times?"

"This is just the first step. We'll talk about it after we finish watching it. We'll talk about it after we finish watching it."

"Chief Engineer Gao wouldn't joke with people, just watch it honestly."

"..."

Amid everyone's discussions, Gao Zhendong hit the Enter key.

DJS-60D is slightly slower than DJS-59 because it is a castrated version.

It took more than twenty seconds, and everyone became more and more curious during the boring wait.

"As you can see, it takes our DJS-10D more than 8 seconds to perform a simple 60 59-bit binary integer multiplication. I can tell you that I have also tried the DJS-, which is a little better, but only a little bit, about seconds."

DJS-59和60D，一个指令周期是4个时钟周期，一次8位乘法运算平均需要25个指令周期，也就是100个时钟周期。

10 calculations require about 1000 million clock cycles, and the speed of these two computers is about 0.6~0.8MHz, which is 60 to 80 clock cycles. In other words, it can perform about 1 to 6000 calculations in 8000 second, plus some basic judgments and jumps, and that's the number.

I have calculated the origin of this time for everyone. After all, most of you here are working on radar, not necessarily on computers, so it is still unclear how this number came about.

Gao Zhendong added: "Moreover, I used the most efficient assembly language for programming here, and discarded all unnecessary operations, reducing judgments and jumps to a minimum. In other words, if we only calculate the computing time, this time can be reduced a little, but not much."

Gao Zhendong explained it very clearly. Many of the people present here have used computers to process radar data. If they could calculate it, everyone would not have to rack their brains.

"Well, Mr. Gao, you are right. Moreover, 8-bit integer calculations are of very limited significance for our processing of radar signals."

Gao Zhendong smiled and nodded: "Yes, this is why I invited you all here. The DJS series computers are extremely weak in digital signal processing."

The DJS series here includes not only DJS-59/60D, but also other DJS series computers, such as those with vacuum tubes.

Everyone seems to have understood a little bit. It seems that Chief Engineer Gao wants to solve this problem to some extent today.

After Gao Zhendong finished speaking, he turned around and started another program on the DJS-60D.

"I am now inputting two 16-bit floating point numbers. Next, let's see how long it takes to multiply two 10-bit floating point numbers 16 times."

We didn't change the machine and we are still using this machine. We are all confused.

If 8-bit integers are already so difficult to calculate, wouldn't it take a lot of time to calculate 16-bit floating-point numbers?
Some comrades who are not familiar with Gao Zhendong even regretted coming here. Isn't this a waste of time?
Then, something shocking happened. After Gao Zhendong pressed the Enter key, in just one second, the computer showed that the calculation was complete and displayed the calculation time, 0.863 seconds!
What's going on? Who am I? Where am I? What the hell is this computer in front of me?

Everyone has already had this feeling, this thing is really unscientific!

The same computer takes more than 8 seconds to calculate an 20-bit integer, but only 16 seconds to calculate a 0.8-bit floating point number?

This is cheating.

Although everyone knew that Gao Zhendong would not do such a trick in such an occasion, this data undoubtedly exceeded everyone's imagination, including the leaders of the Defense Work Committee and the chief engineer.

They were not worried that Gao Zhendong was cheating, they were simply shocked by the increase in this number.

Before they could say anything, one of their comrades exclaimed, "Impossible! Absolutely impossible!"

Although the other comrades did not say it out loud, the expressions on their faces revealed the same thought: This is impossible. Even if you can make the DJS-60D fly, it can't be that fast!

Maybe there is one that can calculate that fast, but it can't be that small! But the big ones in China can't calculate that fast either.

Gao Zhendong was not angry when he heard this. He knew that this result was indeed incredible. He laughed and said, "Comrades, do you think I am cheating? Haha... You guessed it right. Compared with the DJS-60D in your hands, mine is indeed cheating."

Ah, that's all right. Some comrades finally felt like they were back to reality. You should have said you cheated earlier, but what's the point of cheating? It's better to gather everyone together to watch you cheat.

Gao Zhendong: Yes, I just want everyone to come and see me, ZB.

However, some comrades knew that Gao Zhendong would never be so unreliable. They looked at him curiously and said, "I want to see what you are up to. I really want to know."

Gao Zhendong then changed the subject, pointing to a circuit board with many lines directly connected to the DJS-60D circuit board and said with a smile: "I used this thing to cheat. With it, the DJS-60D can complete these 1 10-bit floating point operations in 16 second. In fact, the DJS-60D is just issuing commands. The real calculations are done by it!"

Gao Zhendong has directly connected this hardware multiplier to the internal bus of the DJS-60D and can operate it directly without the need for an external bus for communication, which greatly saves time.

“Ah~~~~!!!!”

The whole place was in an uproar!

Now I feel relieved. Chief Engineer Gao is definitely not joking. If he said that the calculation was completed by this board, then it was definitely completed by it.

The leader of the Defense Work Committee laughed and said, "Comrade Zhendong, your cheating method is extraordinary. Ordinary people can't cheat like this."

Everyone laughed together, but before they finished laughing, they suddenly realized, what a relief!

Given the size of this thing, it's impossible for it to complete such a huge and complex calculation within a second. That's not scientific at all, right?

"Chief Engineer Gao, I still can't figure out why such a small circuit board can calculate so quickly? Is it only used for calculating special numbers?"

What this means is that it only works so fast for a few specific numbers you enter?
They also know this method and can use it. The simplest one is the table lookup method, which is to look up the result in the data table based on the input number. For example, if there are two operands for an operation, a two-dimensional table can solve the problem.

Gao Zhendong also understood what he meant. In fact, the simplest way to implement a 4-bit integer hardware multiplier on CPLD/FPGA using a language such as VHDL is to use a table lookup method.

However, it is simply a fantasy to use the table lookup method for general 16-bit floating-point number calculations.

Gao Zhendong smiled and said, "How about this, comrade, you come up and try it. Input two floating point numbers and let it calculate them. See if the time and result are correct."

No matter how much I say, you will understand once you try it.

This comrade was also very clear. He said, "Come now, this is a big matter and we cannot be vague about it."

He walked up and entered two 10-digit decimal numbers. The minimum precision of a 4-bit binary floating point number is 16 significant digits, which is enough, and then he hit the Enter key.

Under the watchful eyes of everyone, in less than a second, the answer and time popped up on the screen.

0.871 seconds!
The time numbers have changed, but it’s the same as if they haven’t changed!
The time numbers were thrown aside, and almost all the comrades picked up paper and pen to calculate the result of the formula entered by this comrade.

The speed is not fast, and it takes a while for any ordinary person to multiply two 4-digit numbers on paper.

Finally, some people figured it out.

"I miscalculated!"

"That's right!"

"That's right!"

However, there are obviously more people who say that it is correct.

(End of this chapter)