Self modifying code, lambda calculus - Re: ENIAC programming

Jon Elson elson at
Fri Sep 18 11:13:00 CDT 2015

On 09/17/2015 11:19 PM, Guy Sotomayor wrote:
> On 9/17/15 8:55 PM, Jon Elson wrote:
>> I think the later X86 machines have a tiny block of patch 
>> microcode that is available to the OS to put special 
>> routines into.
> Certainly not Intel CPUs.  All of the microcode patches 
> are loaded via special instruction sequences
> (described in the SDM).  The microcode patch RAM is in the 
> CPU and not visible to S/W.
OK, thanks, I knew there was this patch RAM, but didn't know 
the purpose.


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