[GTALUG] reverse engineering

[James Knott]

On 03/29/2019 08:30 PM, Dave Collier-Brown via talk wrote:
>
> Zylog still builds z80s, albeit in India --dave
>
> On 2019-03-29 3:51 p.m., Stewart Russell via talk wrote:
>> On Fri., Mar. 29, 2019, 11:28 Kevin Cozens via talk, <talk at gtalug.org
>> <mailto:talk at gtalug.org>> wrote:
>>
>>
>>     It was just something I noticed. I was partly surprised that
>>     ghidra included
>>     some older processors in their list of ones for which they can
>>     decompile code.
>>
>>
>> Z80 will still show up in industrial control things. It seems very
>> hard to kill. 
>>
>> At least we might have seen the end of 1802s in real applications. It
>> is still popular for some hobbyists, though. 

When designers design custom chips, they rely on logic libraries, which
provide common functions, including CPUs.  So the designer would choose
a CPU, add memory and I/O and "compile" the new chip.  The libraries
contain many historic CPUs, as they provide all the function and
performance needed.  If the job can be done with a 4 bit CPU, such as a
4040, there's no need for a 64 bit CPU.  One factor that's critical with
chip design, is "real estate".  The smaller you can make it, the cheaper
it will be and provide higher yield.  Several years ago, I used to
repair point of sale terminals that had a custom chip built around a Z80
core.