Chapter 604 Come, everyone, look at me ZB!
There are also people who don't know him, mainly comrades who are engaged in radio communications. Regarding command vehicles, the technical ones are mainly people from the armored vehicle factory.
"Who is this? It seems that everyone knows him, and he seems quite powerful." A comrade quietly asked the person next to him.
"Well...it's pretty awesome, but I can't say who it is. But since you attended the meeting anyway, I guess you'll know it soon."
It seems that you will know soon, but I still can't say it casually now.
When most of the comrades working on radar saw Gao Zhendong come in, they immediately knew that today's matter was absolutely inseparable from high technology, and it was very new, so new that no one had seen or even heard of it. kind of.
Looking at the specially prepared set of equipment with slightly complicated wiring on a table in the conference room, they were even more certain that the one put out by the National Defense Work Committee this time was probably another big one.
After a while, the leaders of the National Defense Work Committee and the chief engineer also came. For Gao Zhendong to do such a no-brainer job, the leaders had to come.
First of all, he was curious about what could make Gao Zhendong so excited and mobilize his troops.
Secondly, if there is any problem, he can help Gao Zhendong by being there.
"Comrades are all here, right? The meeting will begin. Comrade Zhendong, where are your goodies? Take them out, hahaha."
The leader was very direct and did not have any opening remarks. The main reason was that he did not know what opening remarks to make. He did not know what Gao Zhendong was going to come up with and could not say anything.
However, these words he said were very particular. He did not say "the good things you said you wanted to bring out", but "your good things". This made people think that this meeting was the idea of the National Defense Work Committee. If there is any problem, Gao Zhendong cannot be blamed.
Gao Zhendong nodded and said with a smile: "Yeah, okay. Before I introduce this thing, let's watch me do two calculation experiments."
Computational experiments? Can this thing be tested? Everyone is very curious.
Then they saw Gao Zhendong turn on the conspicuous computer in the venue.
After the screen lit up, Gao Zhendong entered the instruction to use the DJS-60D body to perform 100,000 multiplication operations, but instead of hitting Enter, he turned around to explain what operation he was about to perform.
After listening to his words, everyone at least understood what his first step was to do.
"Repeating 8-bit multiplication operations 100,000 times? I don't see the point in it yet."
"Well, and the multiplication of 8-bit integers doesn't make much sense, so what if we count it 100,000 times."
"This is just the first step. We'll talk about it after reading it. We'll talk about it after reading it."
"General Manager Gao won't make fun of others, just be honest."
"..."
Amid everyone's discussion, 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 while waiting in boredom.
"As you have seen, simply performing 100,000 times of 8-bit binary integer multiplication takes more than 20 seconds on our DJS-60D. What I can tell you is that I have also tried the DJS-59 and it is better. But it’s just a little bit, maybe twenty seconds.”
For DJS-59 and 60D, one instruction cycle is 4 clock cycles, and an 8-bit multiplication operation requires an average of 25 instruction cycles, which is 100 clock cycles.
100,000 operations require about 10 million clock cycles, and the speed of these two computers is 0.6~0.8MHz, which is 600,000 to 800,000 clock cycles. In other words, one second can calculate about 6,000 ~8000 times or so, plus some of the most basic judgments and jump time, that’s it.
Let me calculate the origin of this time for everyone. After all, those here are engaged in radar, not necessarily computers. It is still unclear how this number came about.
Gao Zhendong added: "Moreover, here I use the most efficient assembly for programming, and throw away all unnecessary operations, simplifying judgments and jumps to the minimum. In other words, pure calculations In terms of time, this time can be reduced a little, but there is not much that can be reduced.”
Gao Zhendong explained very clearly. Many of you here have used computers to process radar data. If you can calculate it, you don't have to scratch your head.
"Well, Mr. Gao, you are right, and 8-bit integer calculation has very limited significance for us to process radar signals."
Gao Zhendong smiled and nodded: "Yes, this is why I invited you all here. DJS series computers have extremely weak performance in digital signal processing."
The DJS series here includes not only DJS-59/60D, but also other DJS series computers, such as vacuum tube ones.
Everyone finally understands 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 on the DJS-60D and started another program.
"What I am inputting now are two 16-bit floating point numbers. Next, let's take a look at the calculation time of multiplying two 16-bit floating point numbers 100,000 times."
We didn’t change the machine, we were still on this machine, and everyone was numb.
8-bit integers are calculated like this, but 16-bit floating point numbers won't cause time explosion?
Some comrades who are not familiar with Gao Zhendong even regret coming here. Isn't this a waste of time?
Then something happened that shocked them. After Gao Zhendong pressed the Enter key, one second, just one second, the computer showed that the calculation was completed, and the calculation time was displayed, 0.863 seconds!
what happened? who I am? Where am I? What the hell is this computer in front of me?
Everyone has already felt this way, this thing is really unscientific!
The same computer takes more than 20 seconds to calculate an 8-bit integer, but only takes 0.8 seconds to calculate a 16-bit floating point number?
This is cheating.
Although he knew that Gao Zhendong would not be able to pull off such a small trick on such an occasion, this data undoubtedly exceeded everyone's imagination, including the leaders of the National Defense Work Committee and the chief engineer.
They were not worried about Gao Zhendong cheating. They were simply shocked by the increase in this number.
Before they could speak, one comrade exclaimed: "Impossible! Absolutely impossible!"
Although the other comrades didn't say anything, the expressions on their faces showed the same thoughts. This is impossible. Even if you make the DJS-60D fly, it can't be that fast!
Maybe there is something that can calculate that fast, but it can never be so small! But the big guys in China are not that fast.
Gao Zhendong was not angry after hearing this. He knew that the result was indeed incredible. He smiled and said: "Comrades, do you think I am cheating, haha... You guessed it right. Compared with the DJS-60D you have, I This is indeed cheating.”
Ah, that's okay. Some comrades now feel like they've returned to reality. You told me you were cheating, but what's the point of cheating? Let's get 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, and looked at him curiously, "I want to see what kind of medicine you sell in your gourd, I really want to know."
At this time, Gao Zhendong changed the subject, pointed 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 be used in 1 second." It has completed these 100,000 16-bit floating point calculations. In fact, DJS-60D is just sending commands, and it is the one that completes the real calculations! ”
This hardware multiplier has been directly connected to the internal bus of DJS-60D by Gao Zhendong and can be operated directly. It no longer requires a peripheral bus for communication, which greatly saves time.
"Ah~~~~!!!"
The whole place was in an uproar!
Now I felt at ease. There was no way Chief Engineer Gao was joking. If he said the calculation was done by this board, then it was definitely done by it.
The leader of the National Defense Working Committee smiled and said: "Comrade Zhendong, your cheating method is like a fairy's fart - it's extraordinary. Ordinary people can't do this cheating."
Everyone laughed together, but before they finished laughing, they suddenly realized what they were doing!
The size of this thing can't complete such a huge amount of complex calculations in one second. It's not scientific at all, right?
"General Engineer Gao, I still don't quite understand why such a small circuit board can calculate so fast? Is it only used for calculations of special numbers?"
What this sentence means is, can it only be 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 looks up the result in the data table based on the input number. For example, for an operation with two operands, a two-dimensional table can solve the problem.
Gao Zhendong also understands what he means. In fact, the simplest way to implement a 4-bit integer hardware multiplier on a CPLD/FPGA using a language such as VHDL is the look-up table method.
But if the lookup table method is used for general 16-bit floating point calculations, it is tantamount to a fantasy.
Gao Zhendong smiled and said: "Well, comrade, come up and try it. You enter two floating point numbers and let it count. See if the time and result are correct."
It's easy to tell, and you'll know it once you get started.
This comrade is also unambiguous and will come as soon as he comes. This is a big matter and there is no room for ambiguity.
He walked up and entered two decimal 4-digit decimals. The minimum precision of a 16-bit floating-point number is 3 significant digits, which was enough, and then hit the Enter key.
In full view of everyone, in less than 1 second, the answer and time popped up on the screen.
0.871 seconds!
The time numbers have changed, but it’s the same as nothing!
Time figures were thrown aside by everyone. Almost all comrades picked up paper and pen and calculated the results of the calculations entered by this comrade.
It's not fast, and it takes a while for any ordinary person to calculate the multiplication of two 4-digit numbers on paper.
Finally, some people figured it out one after another.
"Wrong calculation!"
"That's right!"
"That's right!"
However, there are obviously more people who say they are right.
(End of chapter)