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Old 01 June 2016, 17:09   #287
Ya' like it Retr0?
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Join Date: Jul 2005
Location: United Kingdom
Age: 43
Posts: 9,768
/Ops (sorry for the off-topicness)

There is a monumental difference that would take an entire thread in itself to clarify the difference between emulation and field programmable arrays - but in short

Originally Posted by demolition View Post
I don't like the word either as it can be misleading but depending on which definition you take on the word, it is not entirely incorrect that an FPGA implementation of a 68000 is emulating a real 68000. Using that definition, a 68020 is also emulating a 68000 since it can run most of the same software but is not a real 68000.
I am sorry my friend I have to disagree on this point - a silicon gate is just a logic gate - a field programmable device is just that a set of logic gates - that process exactly the same as any processor - there is no emulation - to call it that can propagate an underlying lack of knowledge to what a processor is - which is simply a set of logic gate blocks

The only difference with FPGA's (Field Programmable Gate Arrays) processors and ASIC (Application Specific Integrated Circuit) processors is that logic gates are volatile and require a load of its gate arrays on power up.
You would still call a ROM a ROM if it was written to a electrically erasable read only memory (EEPROM) or on a one time programmable read only memory (OTPROM) - one is not emulating another. Should I now bring up MASK ROMS?
Besides most ASIC devices over the last donkeys age have been developed from both Complex Programmable Logic Devices (CPLD's) and FPGA implementations - I suspect that the Vampire could go in that direction if there was a large enough market.

FPGA (why)
Rapid development of processing features
Debuging and refinement
Expensive in single quantities[*]

ASIC (why)
Cheaper to produce over large quantities
Generally higher clock speeds
Large minimum order quantities
Errors are propagated throughout the production run

[*]FPGA's have become both inexpensive and more complex allowing for specialist equipment (low volume) to be produced for various markets - the retro-computer scene has been one of these for some time.

Originally Posted by demolition View Post
But when most people here hear the word emulation, they think of software like WinUAE, and that is something completely different so I'd also prefer to not use the word emulation in conjunction with FPGAs.
Just think for a moment the level of abstraction here - there is the kernal hardware layer, there is the communication layer and there is the operating system layer, then there is the software layer - which in the Case of UAE arguably repeats this again through approximation.

In most cases software Emulation is very much removed from the hardware

Originally Posted by Lord Aga View Post
"It still isn't a 68000."
So it's an emulator ?
No, it is a 68020, it has the same logic gate instructions as the 68000 (some more refined) plus additional instructions - it is a completely different processor - one that can manipulate data in 32 bits instead of 16

Of course, all in all we are only arguing what the root meaning of a word used in a given context e.g. computing - From this context I would ague that emulation is approximation through many layers of software - that does not mean emulation cannot match or surpass its intended platform as in a lot of way's WinUAE has shown us that is has.

FPGA's are not not emulation, they are an implementation they do not have processing overheads associated with the most commonly understood software emulation.
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