OMAP-L138: Compress / Optimise AIS by converting repeating byte patterns to Section Fill commands where possible

Fran Davies

Part Number: OMAP-L138

I have a firmware binary with an AIS that uses Section Load commands. In some places, blocks of repeating bytes occur.

I am trying to reduce the flash memory used for AIS by inserting Section Fill commands, where possible.

For example, a 256 byte block of 0x00 could be swapped for a Section Fill command filling 256 bytes with pattern 0x00, followed by a Section Load command for the remaining data.

The same is true for patterns of length 2 and 4 bytes. If the sequence length is >32 bytes, space can be saved.

I wish to process the entire AIS, identifying repeating patterns and inserting Section Fill commands where appropriate.

Is there already a tool to do this?

(I do not have access to the source code, I am modifying the binary using Python.)

over 5 years ago

0 Yordan Kovachev over 5 years ago

TI__Guru**** 161600 points

Hi,

Which Processor SDK are you using: RTOS or Linux, in both cases the AIS is generated by the bootloader code provided in the sdk, so you can modify directly the source code.

Modifying the binary using python is not recommended.

Best Regards,
Yordan

0 Fran Davies over 5 years ago in reply to Yordan Kovachev

Prodigy 30 points

Hi, thank you for your response.

The device uses RTOS.

Apologies, I may be missing something...

I do not have access to the firmware source code, only the compiled binary.

Is there a way to unpack AIS binary and rebuild it with a preference for Section Fill where patterns recur?

0 Yordan Kovachev over 5 years ago in reply to Fran Davies

TI__Guru**** 161600 points

Hi,

I am not aware of ways to unpack AIS binary. My guess is you use MCSDK RTOS and not Processor SDK RTOS, so you can download MCSDK RTOS from here:

And you can find details on AIS image generation here:

For Processor SDK RTOS you should use these links:

Best Regards,
Yordan

0 Fran Davies over 5 years ago in reply to Yordan Kovachev

Prodigy 30 points

Thank you for your help.

0 Norman Wong over 5 years ago in reply to Fran Davies

Guru 26430 points

There are number of places to look for AIS code...other than one tiny file in a huge SDK.

Once AISGEN is installed, the install directory has AIS_Util.cs file. It is fragment of a larger system.

The DaVinci Serial Boot and Flashing project, hosted here:
sourceforge.net/.../
I think this is where TI publishes the system that has AIS_Util.cs. Not easy to navigate.

U-boot has some source. see file named tools_aisimage.c.

Here on this forum is gew threads. Of interest is Eliot's Python work
e2e.ti.com/.../119062

Most of the code is concerned with decoding the AIS file for programming. Encoding should be a matter of reversing the operations.

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OMAP-L138: Compress / Optimise AIS by converting repeating byte patterns to Section Fill commands where possible