Fix overflow when negating minimum int16_t value in precoding
This closes#955
It prevents undefined behavior caused by the minimum int16_t value
(-32768) in two's complement representation. Because possible negation
by multiplying with -1 during precoding cause an overflows since +32768
cannot be represented in 16-bit signed integers and end up again in
-32768 because of overflow, here reveald by using the SIMD functions.
Workaround we use a slightly smaller number than 1 in Q15 Format to
prevent this error. Q15 representation of (integer value -32767) -1 +
2^-15 = -0.999969482421875
This avoids the issue of compare_exchange_weak always failing. The issue
was that `store()` is not equal to `exchange()`. `exchange` uses memory
copy while `store()` copies the value representation of the argument, which
is not always the same thing.
- Added event parameter for recording which is reflected in the filename
- Added event in the UE for DLSCH NACK
- Added program name to the filename for ease of identification
- Reworked spinlock to use atomics
This commit introduces the following changes to ImScope:
- Added the ability to record IQ data using the same mechanism as ImScope.
- Added a new executable target `imscope_iq_file_viewer` for viewing IQ files.
- Introduced a command line argument `--imscope-record` that enables data recording mode.
- Refactored a lot of the scope code
Usage:
- To record IQ data, run a modem with `--imscope-record` flag.
The recording happens whenever a modem calls dumpScopeData, which currently is
done only in gNB on PUSCH DTX and PUSCH CRC NOK.
There is a limit of ~1GB of files written by the thread in a signle run to avoid
accidentally exhausting disk space.
If a directory `imscope-dump` is available the data will be recorded there in .imscope
files. Otherwise files are written to the directory the modem was run. This is done so that
the directory can be mapped in a docker container.
- To view recorded IQ files, use the new executable `imscope_iq_file_viewer`. This can be done by running:
```
./imscope_iq_file_viewer <path_to_iq_file>
```
Replace `<path_to_iq_file>` with the path to the IQ file you want to view.
Imscope updates
- Using imgui docking branch - allows window docking.
- Moved scopes to different windows to allow docking.
- Disabled scatterplot for time domain samples - issues with amount of
vertices caused segfaults.
- Disabled IQ heatmaps for RX IQ samples on gNB and UE - this was
incorrect and currently I don't know how to fix it. This will be
reenabled once it is.
- added a simple menu and disabled demo windows by default.
- Using imgui docking branch - allows window docking.
- Moved scopes to different windows to allow docking.
- Disabled scatterplot for time domain samples - issues with amount of vertices caused segfaults.
- Disabled IQ heatmaps for RX IQ samples on gNB and UE - this was incorrect and currently I don't know
how to fix it. This will be reenabled once it is.
- added a simple menu and disabled demo windows by default.
Implement run-to-completion for processSlotTX. This is achieved by using a new
dynamic_barrier_t which allows to specify callback after the first join has been
made.
Add functional DFT test
- clean up code on (i)dft calls
- add DFT test for some DFT sizes against trivial implementation: it
tests a simple square signal in only real values
- correctly scale DFT-16
Robert Schmidt