Hi Brad,
On Thu, 23 May 2013 11:13:53 -0600, Brad Walker bwalker@musings.com wrote:
Sorry for being delayed on getting back to you on this. Work issues took hold.
There were several good questions.
Let me give you some background.
I am working at a start-up. We are building a new processor and system for that new processor. So we have hardware work and software work to get through.
Part of my reasoning in asking the question about a disassembler is becuase there is a reference to BedBug in the manual. http://www.denx.de/wiki/view/U-Bootdoc/BedbugEmbeddedDebuggerCommands . As well as, the BedBug debugger is in the source code.
So I'm trying to understand at a high level if I can utilize this work to help me. Or should I just go and implement this independently.
Why not just use JTAG? We are doing new processor design, so it's not defined if the system will even have a JTAG interface. There are lots of systems that do not have a JTAG interface.
Why not use use objdump? We are in the process of porting binutils, so I currently don't have an objdump to use. I do have a manual disassembly routine that we created in h/w design to help us. But, until binutils has been ported, there is no objdump.
I think the big issue that is confusing to me is why is BedBug still in U-Boot? Should i try and graft my work into BedBug? If so, then I'm happy to do the work and contribute it back to the group. But, if not, then I'll just go ahead implement the work independently.
Hopefully, this makes sense. Feel free to ask questions.
The way I understand your project, I wonder why you want to disassemble code at all: if you manage to get U-Boot running on your target with BedBug support for your CPU enabled, this means you have a working gcc+binutils, which in turn means you have a toolchain, including an assembler, that works well enough for bedbug to become pointless.
Compare the bedbug and objdump/gdb options: on the one hand you get a crude debugger and disassembler that will only run from U-Boot and will be practically useless for debugging say a Linux kernel or U-Boot itself; and on the other hand, with objdump you get a disassembler that will work on just about any binary, and with gdb, you get a debugger that will debug anything from U-boot to userland apps.
Also, I *very* strongly suggest that you integrate *some* debugging interface, based on *some* industry standard. Seeing as you're working on a brand new, untested so far, silicon, such a debugging interface is an absolute must IMO.
-brad w.
Amicalement,