Re: [Qemu-devel] [PATCH v3 2/2] Add Nios II semihosting support.

[Sandra Loosemore <sandra@codesourcery.com>]

On 05/18/2018 02:19 PM, Julian Brown wrote:
> On Fri, 18 May 2018 21:52:04 +0200
> Marek Vasut <marex@denx.de> wrote:
> 
>> On 05/18/2018 09:23 PM, Julian Brown wrote:
>>> This patch (by Sandra Loosemore, mildly rebased) adds support for
>>> semihosting for Nios II bare-metal emulation.
>>>
>>> Signed-off-by: Julian Brown <julian@codesourcery.com>
>>> Signed-off-by: Sandra Loosemore <sandra@codesourcery.com>
>>
>> Is there some documentation for this stuff ? It looks interesting, but
>> how can I try it here ?
> 
> There's no documentation AFAIK apart from that the entry points are
> the same as m68k, semihosting is invoked with "break 1", and r4/r5 are
> used for passing arguments. I'm not actually sure how you can try this
> stuff without our startup code or other infrastructure (that I'm pretty
> sure we can't divulge). Sandra, any ideas?

I don't see any reason why we couldn't contribute libgloss support, 
except that I don't have time to write such a BSP right now.  :-(  I 
recently did this for C-SKY, though, and the semihosting parts were just 
a straightforward copy from the m68k port.

FWIW, CodeSourcery's Nios II ELF toolchains have been using this 
semihosting protocol with a different BSP library all along, and Altera 
also supports it in the proprietary simulators they've provided to us 
for testing.

-Sandra