64/32 bit

Since it seems that the 64bit ARM processors can’t be switched from 64 to 32bit and back – could this be emulated – to help in developing a 64bit RO?

Eh?

There is no problem with 64 bit chips which support 32 bit modes switching between then – the problem is they are dropping 32 bit modes altogether and new high end processors are 64 bit only. The whole 32 bit instruction set then has to emulated, just as if it were running on a non ARM processor.

There is no problem with 64 bit chips which support 32 bit modes switching between them

No, but do they have a distinction between privileged and unprivileged 32-bit modes?

Some of the newer ones don’t bother with privileged 32-bit modes, so something like the (seemingly dormant) Linux Port is needed for those, rather than a full RISC OS.

Some of the newer ones don’t bother with privileged 32-bit modes

I thought I’d heard that somewhere. All this v8 stuff came along after my time working on the ARM ARM…

My mistake – I thought when the ARM chip was put into 32bit mode – there was no way back to 64bit without a total reset.

IE RO being developed – being part 64/32 bit as modules are updated.