1991 Starting from the core

The two Sol architecture CPUs participating in the evaluation this time have a core frequency of 75MHz, using the most advanced 0.5 micron process technology, integrating the enhanced multimedia instruction set MMX developed by Yuanxin, and benefiting from the 0.5 micron process The technology allows it to integrate a 64K full-speed L2 cache - its operating frequency is consistent with the core frequency.

At the beginning, the two teams had heated discussions on many issues such as whether to integrate the second-level cache, how much to integrate, full speed or half speed, etc. In the end, Su Yuanshan made the final decision, letting Xinghai side adopt a milder and more market-oriented approach. plan.

In Su Yuanshan's plan, Xinghai's CPU department will be the main force in joining forces with AMD to challenge INTEL's throne in the next few years, so the market's acceptance must be taken into consideration. In contrast, the CPU department of Yuanxin will depend on the development of the situation - the best vision is to obtain Intel's full authorization for the X86 instruction set next year, which is good for you and me.

We almost had to take a curveball route to save the country. After Xinghai goes public next year, we will rely on the funds raised to establish a new joint venture in mainland China with Yuanxin and Texas Instruments, in which Xinghai will dominate. Then the new company will launch a CPU designed by Yuanxin.

The worst thing is that the Yuanxin CPU department will be directly converted into a scientific research unit, dormant for another five years, and then go straight to 64-bit processors.

Therefore, it is not difficult to understand that Su Yuanshan even pays more attention to cyrix than the CPU team of the Shanghai Science and Technology Park.

…

The camera faithfully recorded the progress of each test.

When the test results were counted in real time, all testers, including the design team, showed expressions of disbelief.

"The role of the second-level cache is actually so great?" Holpus, Claude's deputy and the one who had been interacting with Li Mingliu's team, had been suppressing his excitement. When the test was halfway through, he finally couldn't help but exclaimed. .

"It should be the enhancement of the command hit rate, which greatly improves the efficiency of command execution." Claude's face was calm, but he could not suppress his surprise: "In addition, the overall architecture is much more advanced than the Pentium."

Although in the design and simulation stage, the capability of this CPU can be judged by calculation alone, it is a recognized truth in the field of chip design that "it is easy to understand on paper, but you will never know that this matter will be taped out."

Everything is virtual until tape-out is completed.

"Now it seems that the biggest problem with this CPU is the cost." Claude took out his mobile phone, looked at the time, and prepared to call Su Yuanshan.

More than half of the test has been carried out, and the quake is ongoing. After the new CPU is paired with a brand-new motherboard, it has even achieved an epic transcendence - the FPS is nearly twice as high as Intel's current strongest Pentium 100MHz.

——Yes, in order to take care of the user experience of Socket 7, Sol CPU did not adopt a new interface, but continued to choose to be compatible with Socket 7, so that it can run on motherboards that support Pentium model CPUs.

But if it really wants to run perfectly, it still needs to be paired with a chipset jointly designed by Meijie and Yuanxin.

"Claude, something's wrong."

Just as Claude pressed the dial button, several computers nearby also completed a series of multiplication and division calculation tests.

This is a test program sent by Yuanxin, which mainly uses a large number of scientific calculations to simulate actual engineering, mathematics and related industry calculation scenarios.

All test results will eventually obtain an accurate result.

“Why are the results from this computer wrong?”

An engineer in charge of the test pointed to the 66MHz first-generation Pentium and looked at the test results with some surprise - now, the other monitor screens have given the test completion time and final score - that is a Pi A number accurate to the fifth decimal place. 3.14159

But the first computer came up with a completely different number. -2021.211

"Try again?" Claude immediately put away his phone and walked to the computer curiously.

After repeating the test, the answer remained the same.

Several people looked at each other, and Claude even forgot to call Su Yuanshan to announce the good news for a while.

After pondering for a few seconds, he whispered: "The test software is the same, and the scores on the other five platforms are the same. There is only one reason..."

"This test is a floating-point division test, which is the responsibility of the CPU. Obviously... there is a problem with the floating-point division of this Pentium 66."

Claude immediately gave the answer with the keenness of an engineer: "If you look for a few more CPUs, look for the first-generation Pentium series."

…

The test engineers quickly found several Pentium CPUs that were launched last year in the test laboratory, with clock speeds ranging from 33 to 66. In addition, they also found second-generation Pentium CPUs with different clock speeds.

To be on the safe side, everyone ran another test on the entire platform, and quickly came to the conclusion that the answer to Yuanxin's floating-point division test tool was unique and unchanging.

——The answer of the Pentium 66 host has not changed. It is still -2021.211, which seems so outstanding.

As the platform changed, everyone became nervous.

Everyone present is an engineer who plays with CPUs. They all know that if a calculation error occurs in a CPU, it is unlikely that there is a problem with one of the CPUs - because if there is a problem with a single CPU, it is most likely to cause a crash during the test or constant results. Change issues.

The BUG result of this machine can be repeated, which means that it may be a design flaw or design error.

Time passed by second by second, and when the replaced platform gave out the results again, everyone looked at each other... There was an emotion on their faces that they didn't know how to express.

All the first generation Pentiums, all the results are wrong!

"Fuck... would Intel make such a mistake?" Haupster glared, hiding the surprise in his eyes.

As a veteran who has been following the pace of Intel since the Cyrix era, Hopst knows very well how powerful the design and manufacturing capabilities of this giant that they have "temporarily defeated" today are in the CPU field.

"Maybe." Claude quickly calmed down. He thought of many possibilities at this moment, but in the end a light fell on his mind - maybe it was a problem with the division table.

In the current FPU unit, in order to increase the speed of floating-point division operations, all chip designers, including Cyrix, use the solution of burning the division table into the core. The benefits are obvious.

But it also brings a trouble because it is "artificial" and not automatically generated by EDA. Then it cannot be simulated in various simulation programs.

So, it can go wrong.

Could it be that Intel made a mistake in the division table during the design process?

Thinking of this, Claude quickly grabbed the phone and started dialing Su Yuanshan's cell phone.

At this moment, the good news is already secondary. It is important to find out which calculation in Yuanxin's scientific computing test software triggered this vulnerability!