Previously it might read an address multiple times if an abstract
command took longer to execute than expected.
The new implementations reads from the target how far it has gotten
along reading memory, and resumes from there if cmderr=busy.
This ended up being a bigger change than I envisioned, but in the end it
deleted more lines than it added, so I'm happy. :-)
The downloaded program now post-increments, and there's no longer an
attempt to read the current address from the target. This made it easier
to fix the problem where at the start of the loop the current address
was already read (in regular entry) or has not yet been read (when the
first round through the loop encountered busy more than once, or busy
was encountered at least once later on).
The interesting new code concerns ignore_prev_addr and
this_is_last_read.
Additionally, I tweaked some debug output, and optimized
riscv_batch_run() when the batch is empty.
Usually incrementing to get the next port is a good idea, but when set
to 0 the idea is to find an arbitrary unallocated port. 1 is almost
certainly not helpful.
This is essential when a test environment asks OpenOCD to listen on port
0, so that the environment can easily discover which port is actually
being used.
The actual implementation of triggers didn't change between those two
versions, so there's no need to duplicate the code.
In the process, I also fixed a minor multicore bug where tselect didn't
always get written on all harts.
This is the only way the spec guarantees that GPRs are accessible, and
depending on the implementation this might be the only way that CSRs are
accessible.
Also changed the debug code that parses out DMI fields to be simpler to
maintain (albeit a little slower).
riscv013_execute_debug_buffer() now automatically clears cmderr if the
command fails. That feels like the right behavior. (It does return the
error to its caller.)
Tim Newsome
Palmer Dabbelt
Liviu Ionescu
Megan Wachs
Gleb Gagarin