How to add section in linker script?

[profprogrammer]

Hello.

I have  array.

char const buff [31];

I want to locate dannyy an array at the given in-memory address.

m_graphics      (RX) : ORIGIN = 0x0003CFF0, LENGTH = 0x00002010  ..........   .graphicstable :   { ...........   } > m_graphics

Share an example of the solution of the similar task.

Share an example of the solution of the similar task.

Share an example of the solution of the similar task.

[DavidS · Accepted solution]

Hi Prof,

Please reference this very good blog: Defining Variables at Absolute Addresses with gcc | MCU on Eclipse 

I tested it with KDS_3.0 and KSDK_1.3 for the FRDM-K64F.

Attached is my project.  The os_tasks.c and ProcessorExpert.ld linker script are the files I modified to test placing buffer into SRAM and also one into Flash.

Snippets from those files:

unsigned char __attribute__((section (".myBufSection"))) buf[128]="holy SRAM batman";	//DES this is in SRAM....look at linker file too
const unsigned char __attribute__((section (".myFlashBufSection"))) fbuf[128]="holy Flash batman";	//DES this is in Flash....look at linker file too

  m_text_2              (RX)  : ORIGIN = 0x000FFF00, LENGTH = 0x00000100

  m_data_3              (RW)  : ORIGIN = 0x20020000, LENGTH = 0x00010000

    /* placing my named section at given address: */

  .myBufBlock 0x20020000 :

  {

    KEEP(*(.myBufSection)) /* keep my variable even if not referenced */

  } > m_data_3

   .myFlashBufBlock 0x000FFF00 :

  {

    KEEP(*(.myFlashBufSection)) /* keep my variable even if not referenced */

  } > m_text_2

Regards,

David

[profprogrammer]

Hi, David E Seymour.

Thanks for the response.

You could prompt how to add my code?

 .grap :
  {
   __LE_START = .;
  WRITEW(0xFFFFFFFF);
  WRITEW(0xFFFFFFFF);
  WRITEW(0xFFFFFFFF);
  WRITEW(0xFFFFFFFF);
   . = __LE_START + 0x0010;
    __CS_TABLE = .;    
    * (.grap)    
  } > m_graphics

I want to fill 16 bytes of xFF.

but Linker gives out an error.

[DavidS]

Try

BYTE(expression)

SHORT(expression)

LONG(expression)

QUAD(expression)

By including one of these four statements in a section definition, you can explicitly place one, two, four, or eight bytes (respectively) at the current address of that section. QUAD is only supported when using a 64 bit host or target. Multiple-byte quantities are represented in whatever byte order is appropriate for the output file format From: http://www.math.utah.edu/docs/info/ld_3.html

Regards,

David

Sent from David Seymour's iPhone 6

[DavidS]

Hi Prof,

I verified the above in attached linker script/file.

ProcessorExpeet.ld

   .myFlashBufBlock 0x000FFF00 :

  {

    KEEP(*(.myFlashBufSection)) /* keep my variable even if not referenced */

  LONG(0xdeadbeef)

  SHORT(0xbeef)

  SHORT(0xdead)

  BYTE(0x10)

  BYTE(0x20)

  BYTE(0x03)

  BYTE(0x04)

  } > m_text_2

Memory Window

0x000FFEE8  ???????? ???????? ???????? ????????  ????????????????

0x000FFEF8  ???????? ???????? 796C6F68 616C4620  ????????holy Fla

0x000FFF08  62206873 616D7461 0000006E 00000000  sh batman.......

0x000FFF18  00000000 00000000 00000000 00000000  ................

0x000FFF28  00000000 00000000 00000000 00000000  ................

0x000FFF38  00000000 00000000 DEADBEEF DEADBEEF  ........ï¾­Þï¾­Þ

0x000FFF48  04032010 FFFFFFFF ????????          . ..ÿÿÿÿ????

Regards,

David