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Forum: ARM programming with GCC/GNU tools How to align load address?


How to align load address?
von Joe D. (jdupre)

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I have some initialized variables that I want to place in a special area 
of RAM.  I want the initialized values stored in ROM after the load area 
for .ramcode.  Like this:

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. = ALIGN(4);

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_ramcodeload = .;     /* at this point "dot" is still in ROM */

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.ramcode : 

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{

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   _ramcodestart = .;

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   *(.ramcode);

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   _ramcodeend = .;

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} > ram

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. = ALIGN(4);

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_where_am_i = .;     /* Now in RAM. This is = _ramcodeend + alignment */

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/* ALIGN(4) only works on the "dot" location marker */

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_usbload = ( LOADADDR(.ramcode) + SIZEOF(.ramcode) );

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.usbram : AT ( _usbload )     /* I want _usbload aligned! */

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{

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   _usbstart    = .;

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   *(.usbram)

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   _usbend    = .;

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} > usbram


But the end of .ramcode stored in ROM may not be aligned. How I do I 
force the linker to align where the initialized values for the .usbram 
section are to be stored in ROM?

  


  




  

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    Re: How to align load address?
  


  

    

      von
      
        Martin Thomas (Guest)
      
      


      
    


    

      
    

    

    

  
  


  

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Placeing . = ALIGN(4); inside the definitions of the output-sections 
should do. This can be checked by looking into the map-file and/or 
symbol-list. If it does not work, please create a minimal example with 
all needed files for a "make all" to reproduce the issue, pack it into a 
zip-archive and attach it to a message.

  


  




  

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    Re: How to align load address?
  


  

    

      von
      
        Joe D.
        (jdupre)
        
      
      


      
    


    

      
    

    

    

  
  


  

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I replaced

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_usbload = ( LOADADDR(.ramcode) + SIZEOF(.ramcode) );

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.usbram : AT ( _usbload )     /* I want _usbload aligned! */

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{

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   _usbstart    = .;

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   *(.usbram)

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   _usbend    = .;

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} > usbram


with

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.usbram : 

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{

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   _usbstart    = .;

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   *(.usbram)

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   _usbend    = .;

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} > usbram AT>flash

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_usbload = LOADADDR(.usbram);


and the alignment happens automatically.

  


  




  

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