[HN Gopher] Investigating SSMEC's (State Micro) 486s with the UCA
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       Investigating SSMEC's (State Micro) 486s with the UCA
        
       Author : apple4ever
       Score  : 57 points
       Date   : 2024-06-28 03:30 UTC (19 hours ago)
        
 (HTM) web link (x86.fr)
 (TXT) w3m dump (x86.fr)
        
       | rwmj wrote:
       | Is it possible they stole / copied Intel's masks?
        
         | adrian_b wrote:
         | They have certainly reverse-engineered some variants of Intel
         | 486.
         | 
         | Nevertheless, they have implemented them in different and
         | better manufacturing processes, so these are not copies of the
         | Intel CPUs, any more than the Compaq computers would have been
         | copies of the IBM computers.
         | 
         | They could have done the reverse-engineering from just buying
         | some CPU samples from any computer shop. It was hard work, but
         | still many orders of magnitude easier than reverse engineering
         | a CPU today.
         | 
         | They could have also stolen some 486 mask sets, which would
         | have made the reverse engineering easier, but this was not
         | necessary, it would have been just a cost-saving measure, with
         | high risks and modest benefits.
        
           | rwmj wrote:
           | Wouldn't it be possible to use the same masks to get a basic
           | "shrink", at least for these rather primitive late 80s /
           | early 90s processes? Likely impossible today because of
           | everything being heavily tuned to the wavelength of the
           | lightsource.
        
             | adrian_b wrote:
             | It depends on how different were the manufacturing
             | processes.
             | 
             | Newer improved processes usually have some extra masks that
             | would need to be generated, besides shrinking the masks of
             | the original set.
             | 
             | Also, the original masks may need to be shrinked non-
             | uniformly, i.e. by modifying the size ratio between holes
             | and covered areas, not by a simple geometric shrink.
             | 
             | Even when the new masks could be generated mostly by
             | shrinking, there is no chance to make such a complex device
             | work in the new manufacturing process without reverse-
             | engineering it. Correct behavior may depend on timing
             | relationships that would be changed in the new CMOS process
             | and which could require small schematic changes for
             | compensation.
             | 
             | After the schematics is extracted by reverse-engineering
             | from etched CPU samples or from a set of masks, it is
             | probably as easy to draw again the masks as to shrink the
             | old masks, even if the old masks or CPU samples would
             | certainly be used as guidance for the floor plan.
        
         | kjs3 wrote:
         | Chinese company, so sure industrial espionage would be the
         | first guess. But to be fair lots of folks reverse engineered
         | the 486 (as shown in TFA). If the performance analysis it to be
         | believed, _something_ was improved, so it 's not an _exact_
         | copy.
        
           | rasz wrote:
           | ? performance is same down to same cycles
        
             | kjs3 wrote:
             | Pls read the article, in particular note the part about
             | power consumption.
        
           | RecycledEle wrote:
           | The cycles per instruction were identical for every
           | instruction.
           | 
           | Power usage dropped by almost a watt or about 25%.
        
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       (page generated 2024-06-28 23:02 UTC)