Re: Discussion: The need of a 65xx HAL

4 de septiembre de 2022 7:50, "Julian Perry" <jp_at_digitaltapestries.com> escribió:

> Hello Tokafondo,
> 
> Sunday, September 4, 2022, 6:24:10 AM, you wrote:
> 
>> I was asking for comments in the 6502.org forum about the need of a
>> 65xx HAL. This discussion had no success there so I'm starting it here again.
> 
>> So what I'm talking about is if would it be of any help the
>> creation of a 65xx HAL that would implement a kind of "high level" language where there would be:
> 
>> - A, B, C... Z registers
>> - Unlimited memory addressing including virtual memory
>> - Unlimited opcodes, including compatible with every known 65xx variant in existence
> 
> Registers are more than just on-board fast access memory: they are plumbed into the ALU and other
> structures, Clearly there was only room for only so many functional registers that could be plumbed
> into the ALU, and whilst the relative paucity of them on the 6502 caused headaches (and
> limitations) for programmers, it helped in the IPC (Instructions per clock) of the overall design.
> I'm sure in any emulation today one could slap in as many as one liked - but what would be the
> point? It wouldn't be a 6502 anymore.


A 80486 CPU is not a 8086 but can run code compiled for a 8086. A 8086 cannot run code compiled for a 80486.

This would be the same. The new, "custom" cores could run code for both original and new instruction sets.