Re: [WIP/RFC] MIPS registers overhaul

Andrew Cagney
2003-05-21T16:38:07Z

>> That came out wrong.
>>
>> I think a GDB debugging a remote 64 bit MIPS ISA should always expect 64
>> bit GPRs and 64 bit FPRs when the ISA is 64 bits, regardless of the ABI.
>>
>> It is quite legitimate, for instance, for GDB to do something as sick-o
>> as clearing the FR bit and then resume the thread. The register
>> save/restore code needs to correctly handle this - be it reject the
>> operation or ``do the right thing''.
>
>
> But when using rda or gdbserver to debug an o32 application, then for
> all intents and purposes we are debugging a 32-bit ISA. The kernel
> will not allow us to change the FR bit. The app will never see 64-bit
> registers. The 32-bit protocol makes more sense here IMO.

From GDB's view point, the ISA is 64 bit.

The fact that a specific remote debug agent choses to use 32 bit
registers is a limitation of that debug agent / kernel. An embedded
target, and I'm pretty sure IRIX 6.5, for instance, don't do that.

Andrew