QualiTI
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QualiTI Introduction
QualiTI is a tool from TI to verify the XDAIS compliance of a certain piece of code, e.g. a codec library. The tool was first published with XDAIS 6.00 and improvements are made with each XDAIS release. Currently, the tool supports C64x+ (64P), C674, and ARM platforms. An older, alternative approach for ARM codec developers non-QualiTI-based approaches is still available.
It is designed as an optional but recommended helper for porting existing free form codec libraries (e.g. open source ones) to the more encapsulated XDAIS or XDM design for making that code correctly plug into any XDAIS-based framework (e.g. Codec Engine).
- Sample QualiTI XDAIS-complaince check screenshot:
At present the QualiTI compliance tool only tests a subset of the XDAIS rule-set - however it does check most of the typical problems that cause integration issues. For example: -
- flags global symbols that do not meet the XDAIS namespace requirements and could clash with other algorithms
- checks for poorly named sections which could cause code or data to be mis-categorized and linked to inconsistent memory sections causing crashes.
- checks for the appropriate IALG, IMODULE, IDMAx (if implemented), IRES (if implemented) interface symbols.
For each rule tested it will emit PASS or FAIL. For each failure, it will indicate precisely what failed, possible reasons for the failure and suggested ways to fix it.
Some details on the tests performed follow: -
Details on tests performed
Rules 8, 9, 10: Namespace compliance
These rules are bundled together simply because we run the same tool to check compliance for all 3.
The rules themselves are: -
- (Rule 8) All external definitions must be either API identifiers or API and vendor prefixed.
- (Rule 9) All undefined references must refer either to the operations specified in Appendix B (a subset of C runtime support library functions and a subset of the DSP/BIOS HWI API functions), or TI's DSPLIB or IMGLIB functions or other XDAIS-compliant modules.
- (Rule 10) All modules must follow the eXpressDSP naming conventions for those external declarations disclosed to the client.
What does namespace compliance mean?
Well, if we run the symbol listing tool nm6x on an algorithm as follows: -
C:\CCStudio_v3.3\C6000\cgtools\bin\nm6x.exe -g fir_ti.l64P
This yields an output something like: -
ARCHIVE: fir_ti.l64P 00000000 T _FIR_TI_exit 00000000 T _FIR_TI_init 00000064 T _FIR_TI_filter 00000000 T _dummy1 00000000 U _memcpy 00000000 T _FIR_TI_activate 00000000 T _FIR_TI_alloc 00000000 T _FIR_TI_control ...
Anything with FIR_TI_ prefix is good, _memcpy is ok since it comes from the allowed RTS functions list in Appendix list of spru352. _dummy1 is bad - 'T' represents 'text' so there's a global function without a decent namespace. This is not namespace compliant.
How to fix this?
QualiTI tells you this too.
Rule 12: IALG interface implementation
- All algorithms must implement the IALG interface
Here we check for the presence of required XDAIS function-table interface entry points. XDAIS requires the following 2 symbols to be exposed: -
- MOD_VEN_IALG - the interface to the list of IALG functions
- MOD_VEN_IMOD - the interface to the list of IMOD functions which extend the IALG functions
Internally again QualiTI uses nm6x to check for the existence of such symbols
Absence of either of these symbols is non-compliance - there should be no characters after the _IALG or _IMOD characters
How to fix this?
- read spru352 & spru360 - they show you how to create an alg with the required interface entry points
- cut/paste/modify a decent 'template' alg like FIR_TI in the Reference Frameworks
QualiTI tells you this too.
Rule 13+: correct linker section names
- Each of the IALG methods implemented by an algorithm must be independently relocatable
This rule requirs that each IALG function be in its own section - this enables clients to link/place them anywhere they want - as opposed to lumping them in with .text
We need a different tool than nm6x for this - we need something that shows the list of sections in the archive.
QualiTI therefore leverages the Codegen XML Perl Scripts Utility package. More specifically it runs sectti.exe
This is the same utility that the XDC Codec Package Wizard uses.
It produces something like: -
Reading from stdin ... Library,Filename,Section,Type,Size fir_ti.l64P,fir_ti.o64,.text:init,CODE,32 fir_ti.l64P,fir_ti.o64,.text:exit,CODE,32 fir_ti.l64P,fir_ti_filter.o64,.text,CODE,32 fir_ti.l64P,fir_ti_filter.o64,.cinit,DATA,24 fir_ti.l64P,fir_ti_filter.o64,.tables,UDATA,16 fir_ti.l64P,fir_ti_filter.o64,.text:filter,CODE,224 fir_ti.l64P,fir_ti_ialg.o64,.text:algNumAlloc,CODE,32 fir_ti.l64P,fir_ti_ialg.o64,.text:algMoved,CODE,32 fir_ti.l64P,fir_ti_ialg.o64,.text:algInit,CODE,64 fir_ti.l64P,fir_ti_ialg.o64,.text:algAlloc,CODE,128 fir_ti.l64P,fir_ti_ialg.o64,.text:algFree,CODE,64 fir_ti.l64P,fir_ti_ialg.o64,.text:algDeactivate,CODE,32 fir_ti.l64P,fir_ti_ialg.o64,.text:algControl,CODE,64 fir_ti.l64P,fir_ti_ialg.o64,.text:algActivate,CODE,32 fir_ti.l64P,fir_ti_vt.o64,.cinit,DATA,48 fir_ti.l64P,fir_ti_vt.o64,.far,UDATA,40
Observe: -
- list of sections differentiated by code, const data or uninitialized data
- Subsections for each of the IALG functions are indeed present so we are in compliance.
However: -
- NOTE that we see an entry
fir_ti.l64P,fir_ti_filter.o64,.tables,UDATA,16
This is bad. Absent the sectti script we wouldn't know whether this was code, uninitialized data or const data. Hence the linker may arbitrarily place this in the wrong type of memory (eg L1PSRAM) if not explicitly placed - this is a frequent source of crashes.
QualiTI therefore emits a FAIL if sections found are not subsections of the main compiler sections (.text, .far, .const etc). Since this is an addition to Rule 13 we call this Rule13+.
How to fix this?
- Add #pragma CODE_SECTIONS for each of your IALG fxns
- Rename your sections to be subsections of main compiler sections e.g. .const:tables
- See this example partial link linker command file to find out how to expose the IALG sections Rule 13 needs to see.
Rule 15: library filename & filetype
- Each eXpressDSP-compliant algorithm must be packaged in an archive which has a name
that follows a uniform naming convention
Pretty straightforward - your archive name format needs to match Rule 15 e.g. fir_ti.l64P is ok but myLib.lib is not
It also has to be an archive - not a partial link or executable.
How to fix this?
- Rename your lib to match the rule
Rule 20: must declare worst-case stack requirements
- Rule 20 - All algorithms must characterize their worst-case stack space memory requirements (including alignment).
This rule is ever more important to specify accurately now because Frameworks like Codec Engine have methods to specify stack size and the BIOS TSK stacks are allocated on this basis - so if you specify a value too low in your XDAIS algorithm documentation your Codec Engine application will crash.
QualiTI uses the call_graph.exe script to determine worst-case stack usage of the algorithm. It trawls the algorithm's DWARF information to find the cumulative worst-case function and reports it.
NOTE - worst-case stack calculation is dependent on a number of factors due to TI Codegen limitations - if you get a warning from running this script on your alg, please read the documentation of the call_graph.exe (docs\ofd\call_graph.htm) script to determine the cause. A common example is if you build your codec with -ml3. This causes all calls to be far calls - some deficiencies in the generated assembly from Codegen then make it impossible to differentiate far calls .v. indirect calls .v....hence the stack size number reported is wrong. The right way to fix this is not to use -ml3. Far calls were made redundant 3 years ago when linker trampolines became available. Full details on these limitations can be found here.
NOTE - Building your algorithm with -g (debug info) also causes problems in calculating the worst-case stack usage at present. The background to this can be found here. This is typically not a major problem since -g inhibits optimization thus most production libraries do not use -g.
Rules 21, 22: must characterize static data & program memory requirements
- Rule 21 - Algorithms must characterize their static data memory requirements.
- Rule 22 - All algorithms must characterize their program memory requirements.
For rules 21 & 22 the static data & program memory requirements, sectti.exe is again used, this time to get the footprint. The output is folded into the final HTML report.
Rule 25: All C6x algorithms must be supplied in little-endian format
Again this can be determined statically. The information is in each of the object files.
If any file in the archive is not little-endian, this rule will fail.
Rule 26: All static/global data must be far on c6x
There should be no .bss in your algorithm if its for c6x - it is a nightmare for ROMing and also has some total-application-size limits since .bss must be < 32Kb (on c6x).
How to fix this?
- Find the offending data and make it far or const
- Or, rebuild with
--mem_model:data=far
How to run the tool?
The README.txt in packages\ti\xdais\qualiti\ shows how to run the tool. In a nutshell its a RTSC package, so if you know how to run one XDCScript product, you know how to run them all. QualiTI supplies: -
- startqti.bat : batch file that runs the app (Windows)
- startqti.sh : shell script that runs the app (Linux)
Edit startqti and modify the path to match your XDC installation directory.
Once you have setup the environment and specified the MODULE, VENDOR, INTERFACE, and tool-settings, the script will run the tests and generate an HTML report, presenting a brief summary on standard output.
Requirements
The requirements to run this tool are:
| XDAIS | XDC Tools | TI cgtools | TI CG XML tools |
|---|---|---|---|
| 6.10 to 6.22.01 | 3.00.05 or higher | Yes* | 1.20 or higher |
| 6.23 or higher | 3.05 or higher | No | 2.10 or higher |
* TI codegen tools (on Windows they are typically found in C:\CCStudio_<version>\C6000\cgtools)
Note that more info on the CG XML product is available here
Feature Additions
- XDAIS 6.10
- initial support for C64P devices
- XDAIS 6.22.01
- adds support for C674 devices
- adds -g option for launching the QualiTI GUI with an input .qti file
- XDAIS 6.23
- adds support for Arm devices
Download
QualiTI is distributed with the XDAIS product here. Newer versions have more features, so it's recommended to download the most recent release.
See Also
- XDAIS API Reference
- XDAIS Rules and Guidelines
- Top 10 Recommendations for codec producers
- XDAIS download site
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