Memory Section overlay

Dominic Wu

Hi,

I am using CCS4 V2.2 with bios version bios_6_30_03_46. I have been searching on how to do memory overlay in the configuration file, but I couldn't find anything. Is there any possible way to do memory section overlay using the configuration file? For example, I have two memory sections that I placed in DDR2 as follow, how can I make them such that the two memory sections will share the same DDR2 starting address.

Program.sectMap[".sect_a"] = "DDR2";

Program.sectMap[".sect_b"] = "DDR2";

In another word how can I join them as a union similar to what I have done in the past in CCSV3

UNION: run = DDR2

{
.sect_a: {}
.sect_b: {}
}

Also can I explicitly force a a.lib file into a particular memory using the configuration file?

Thanks in advance,

Dominic

over 14 years ago

0 Sasha Slijepcevic over 14 years ago

TI__Mastermind 37985 points

Dominic,
you can't create a union from a config file. You'll have to add your own linker command file. Depending on the version of XDCtools you are using, there are different ways how you would do it.

Also, forcing all sections from a library to a particular memory has to be done from a separate linker command file. What can be done from a config file is to allocate a specific section to a specific memory segment (see http://rtsc.eclipse.org/cdoc-tip/xdc/cfg/Program.html#sect.Map).

Please let me know which version fo XDCtools you are using.

0 Dominic Wu over 14 years ago in reply to Sasha Slijepcevic

Intellectual 515 points

I am using XDC version 3.20.04.68 now, but I might be switch to 3.20.08.88 soon.

Thanks

0 Sasha Slijepcevic over 14 years ago in reply to Dominic Wu

TI__Mastermind 37985 points

Since XDCtools 3.20.05, there are two parameters in xdc.cfg.Program that you can use to specify your own set of linker directives that are added to the linker command file:

http://rtsc.eclipse.org/cdoc-tip/xdc/cfg/Program.html#sections.Exclude
http://rtsc.eclipse.org/cdoc-tip/xdc/cfg/Program.html#sections.Template

The first parameter prevents XDCtools from generating allocations for specified sections. Since Program.sectMap doesn't do anything for you for .sect_a and .sect_b, you can just not add them to Program.sectMap and their allocations won't be generated even if you don't specify them in Program.sectionsExclude. The second parameter lets you specify a file that will be included within the SECTIONS directive, and there you can add unions, allocations for al sections from a library, etc. Instead of repeating the whole documentation for that parameter, I'll just mention that you still need all other section allocations to be added, so pay attention to the example and the parameters $args[1].

The above should work for what you wanted to do. However, if you ever need a complete control of the linker command file, not only the SECTIONS directive, there is http://rtsc.eclipse.org/cdoc-tip/xdc/cfg/Program.html#link.Template. The easist way to use this parameter is to copy the automatically generated linker command file, edit it and have Program.linkTemplate point to it. The drawback of this approach is that whenever you want to change anything memory or section-related in your configuration, you have to go through that process again.

0 Dominic Wu over 14 years ago in reply to Sasha Slijepcevic

Intellectual 515 points

Thanks a lot for your help

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Memory Section overlay