In article ,
Gareth Evans   wrote:
>On 29/05/2020 21:20, druck wrote:
>> On 28/05/2020 12:49, Gareth Evans wrote:
>>> Not forgetting that all instructions encode into 32 bits, so
>>> a compiler based on 64 bit data alone will be struggling to
>>> output dollops of 32 bits, perhaps a variation of the PEEK and
>>> POKE so favoured by early domestiv BASICs?
>>
>> I'm afraid this makes no sense at all. Both ARMv7 (32 bit) and ARMv8
>> (ARMv8) can handle data of 8, 16, 32, and 64 bit widths.
>
>It makes perfect sense in the context of the discussion about a
>Dreadnought language that has ONLY 64 bit variables.

Indeed.

Although I'm not sure I'd describe BCPL as "Dreadnought" - more "light
cruiser" :-)

And now I'm thinking - does the Piv4 (and v3) have a 64-bit data bus, or
does it need 2 memory cycles at 32-bit each to read a 64-bit value. I'd
like to think it has a 64-bit (or wider) databus, but I really don't know.

This is something that's making my retro implementation of BCPL on a
65816 somewhat slower than it might be - the '816 is touted as a 16 bit
CPU, but it's still locked into an 8-bit data bus.

Gordon

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