Tim Barry

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11 years, 1 month ago.

Offsetting the load region

Is there any way to offset the load region? I want to have a secondary bootloader stored in the first few sectors and have my main program starting at 0x00005000. I was hoping it would simply be a case of modifying the scatter file to:

LR_IROM1 0x00005000 0x7B000  {    ; load region size_region
  ER_IROM1 0x00005000 0x7B000  {  ; load address = execution address
   *.o (RESET, +First)
   *(InRoot$$Sections)
   .ANY (+RO)
  }
  ; 8_byte_aligned(49 vect * 4 bytes) =  8_byte_aligned(0xC4) = 0xC8
  ; 32KB - 0xC8 = 0x7F38
  RW_IRAM1 0x100000C8 0x7F38  {
   .ANY (+RW +ZI)
  }
  RW_IRAM2 0x2007C000 0x4000  {  ; RW data, ETH RAM
   .ANY (AHBSRAM0)
  }
  RW_IRAM3 0x20080000 0x4000  {  ; RW data, ETH RAM
   .ANY (AHBSRAM1)
  }
  RW_IRAM4 0x40038000 0x0800  {  ; RW data, CAN RAM
   .ANY (CANRAM)
  }
}

but the compiler doesn't like this. I should point out that I'm using the mbed to develop the software, but I just need the binary file for the offset version as I'm loading this onto a bare metal board.

Any suggestions much appreciated.

Tim

Can you be more specific on how the compiler doesn't like it? And which compiler do you use?

posted by Erik - 04 Oct 2014

I'm using the online compiler. The errors I get are:

Internal Error (0) Compile Task Failed (-242)

or sometimes, without any changes to the program I get:

The build system API returned an empty response (-240).

I've posted the project here: http://developer.mbed.org/users/timbobazza/code/mbed_blinky_offset/

posted by Tim Barry 04 Oct 2014

I think the size isn't correct in your sct file, still I wouldn't expect that to matter, and also with another size I get the same errors.

posted by Erik - 04 Oct 2014

I've figured it out. In startup_LPC176x.s the following lines of code set the CRP at address 0x02FC. The compiler doesn't like this as the address doesn't fall in the load region. If I comment it out, everything compiles fine and runs correctly.

                IF      :LNOT::DEF:NO_CRP
                AREA    |.ARM.__at_0x02FC|, CODE, READONLY
CRP_Key         DCD     0xFFFFFFFF
                ENDIF
posted by Tim Barry 04 Oct 2014
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