Extract the return value in finish_command on Xtensa.

[Andrew Cagney]

> I am working on a port of GDB to the Xtensa architecture.
> 
> Unfortunately, it is impossible on Xtensa to extract the return value once the 'callee' has returned to the 'caller' without analyzing the call instruction (if there was one). Depending on the call instruction, the return value can be in register a6, a10, oder a14.

Puzzled expression.  The ABI should specify which return-value 
convention will be used?

I suspect you'll need to explain a little more about your architecture.

Andrew