Monday, August 2, 2010

Weekly Report #11

Weekly Report #11
Submitted on 2010-08-02
Covers 2010-07-26 to 2010-08-02

Status and Accomplishments
• an elementary version of the mechanism to be able to pass DSP-allocated (stack or heap) buffers to RPC functions is now in place. what essentially happens is that when the GPP side detects a non-CMEM-allocated buffer is passed as a parameter, it uses PROC_read to read from the DSP memory and copy this into a regular GPP buffer which the functions can access.
• bugfixes for RPC functions returning structures - but pointer parameters inside structs still remain an issue and have to be translated manually
• dsp-rpc-posix branch re-synced with c6run trunk, but to no avail (see blockers section)

Plans and Tasks
• the ARM and DSP caches are both disabled for dsp-rpc-posix to deal with cache coherency, but this impacts the memory access performance quite negatively - enable them again and use writeback/invalidate functions to keep caches in sync
• some POSIX functions are still missing from the RPC library since their corresponding header files (with type definitions and all) don't exist for the DSP side. this includes useful things like ioctls - find a way to expose these through RPC

Risks, issues, blockers
• despite all the time I spent on it, I couldn't uncover the cause of the "bus error" that occurs when I compile even the simplest things (such as hello world) with the latest C6Run trunk (so it's not just my synced branch that's troublesome). in some cases it's just "bus error" and the program stopping, in others the PROC_setup fails. the code responsible for these parts hasn't really changed so I'm suspecting it to be a build/configuration issue. due to this and the fact that my primary computer's hard drive crashed (I'm stuck with a silly little netbook!) I haven't been able to try and build C6Run inside OE. I'm not sure if this is just happening for me or the c6run trunk is broken (there are indeed some errors that prevent it from building but they are small and easy to fix)

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