[Libre-soc-dev] Attempt to run baselines: error

Luke Kenneth Casson Leighton lkcl at lkcl.net
Mon May 24 17:10:10 BST 2021

On Monday, May 24, 2021, Lauri Kasanen <cand at gmx.com> wrote:

> > - it's unclear why the log calls blr bclr, makes it harder to grep

because blr is a pseudo-assembler shortcut for the underlying instruction.

or, at least, it better damn well be.

> > - it seems to pass memcpy successfully
> > - there's a few unaligned exceptions, pretty sure it's well off tracks
> > by then

maybe not.  are there actual misaligned memory LD/STs in the original? 64
bit LDs crossing two 64 bit words?

the simulator's memory access is quite unsophisticated at the moment.

> It appears to freak out on the main function's return, the last blr.

i would expect this, if lr on the stack has not been set up correctly to
point to somewhere which ends up executing an "attn" (halt)

> I
> guess that would need special handling in the simulator, when all
> existing tests presumably just end.

 replace the last blr with "halt" (attn instruction)

this is just a difference between bare metal and elf POSIX binaries

normally the OS would have set up the LR for the application to jump back
to, some code which ends the process etc etc etc.


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