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maybe, a BUG of ARM Linker version 4.0 Build 697

Note: This was originally posted on 12th August 2010 at http://forums.arm.com

Here is the piece of code in a C source file.

#pragma arm section rwdata ="cellular_ram"
u8 gv_CFI[256]={0};/* MAN ID DID1,DID2,DID3*/
u16 gv_DIDR;
u16 gv_RCR;
u16 gv_BCRInit;
u16 gv_BCR;
#pragma arm section rwdata

then, in scatter file, somethin like this:
    ER_PRE_INIT_DATA 0xA01FF000 (0x00001000)
   {
      init.ptl(cellular_ram,+FIRST)
      drv_gpio.*(+RW,+ZI)
   }

I want to put gv_CFI and the ohter 4 u16 var together in a fix place.

But, after link finished. I check the MAP file.
I found this:

[color="#FF0000"]   gv_CFI                                   0xa802fe58   Data         128 init.ptl(.bss) [/color]

    gv_DIDR                                  0xa01ff000   Data           2 init.ptl(cellular_ram)
    gv_RCR                                   0xa01ff002   Data           2 init.ptl(cellular_ram)
    gv_BCRInit                               0xa01ff004   Data           2 init.ptl(cellular_ram)
    gv_BCR                                   0xa01ff006   Data           2 init.ptl(cellular_ram)

the gv_CFI is placed wrong.....

How can I deal with this ? Why the linker split it from the other four? They are all .bss. why??

Who can help me?

I'm downloading the latest build of RVCT. I hope it will resolve my problem. ...

After upgrade to RVCT v4.0 Build 821, the same problem.

Then, I tried like this:

u8 gv_CFI[256]={0xFF};

It's done.

Thanks for the help of scott.

Parents

Scott Douglass over 12 years ago

Note: This was originally posted on 12th August 2010 at http://forums.arm.com

#pragma arm section rwdata ="cellular_ram" u8 gv_CFI[256]={0};/* MAN ID DID1,DID2,DID3*/ u16 gv_DIDR; ... #pragma arm section rwdata

[...]
I want to put gv_CFI and the ohter 4 u16 var together in a fix place.

But, after link finished. I check the MAP file.
I found this:

[color="#FF0000"]    gv_CFI                                   0xa802fe58   Data         128 init.ptl(.bss) [/color]

    gv_DIDR                                  0xa01ff000   Data           2 init.ptl(cellular_ram)
    ...

the gv_CFI is placed wrong.....

How can I deal with this ? Why the linker split it from the other four? They are all .bss. why??

The compiler has placed gv_CFI in ZI (.bss) and the '#pragma arm section rwdata=...' does not affect it (because it's ZI not RW). The other four have been placed in RW (because they are small) and are affected by the #pragma. You'll probably find it easier to use __attribute__((section("..."))) instead of '#pragma arm section ...' for controlling data sections; see the manual [url="http://infocenter.arm.com/help/topic/com.arm.doc.dui0491a/Caccache.html"]http://infocenter.arm.com/help/topic/com.a...a/Caccache.html[/url].

Searching the infocenter.arm.com Knowledgebase Articles also turns up [url="http://infocenter.arm.com/help/topic/com.arm.doc.faqs/ka3947.html"]http://infocenter.arm.com/help/topic/com.a...aqs/ka3947.html[/url]
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Scott Douglass over 12 years ago

Note: This was originally posted on 12th August 2010 at http://forums.arm.com

#pragma arm section rwdata ="cellular_ram" u8 gv_CFI[256]={0};/* MAN ID DID1,DID2,DID3*/ u16 gv_DIDR; ... #pragma arm section rwdata

[...]
I want to put gv_CFI and the ohter 4 u16 var together in a fix place.

But, after link finished. I check the MAP file.
I found this:

[color="#FF0000"]    gv_CFI                                   0xa802fe58   Data         128 init.ptl(.bss) [/color]

    gv_DIDR                                  0xa01ff000   Data           2 init.ptl(cellular_ram)
    ...

the gv_CFI is placed wrong.....

How can I deal with this ? Why the linker split it from the other four? They are all .bss. why??

The compiler has placed gv_CFI in ZI (.bss) and the '#pragma arm section rwdata=...' does not affect it (because it's ZI not RW). The other four have been placed in RW (because they are small) and are affected by the #pragma. You'll probably find it easier to use __attribute__((section("..."))) instead of '#pragma arm section ...' for controlling data sections; see the manual [url="http://infocenter.arm.com/help/topic/com.arm.doc.dui0491a/Caccache.html"]http://infocenter.arm.com/help/topic/com.a...a/Caccache.html[/url].

Searching the infocenter.arm.com Knowledgebase Articles also turns up [url="http://infocenter.arm.com/help/topic/com.arm.doc.faqs/ka3947.html"]http://infocenter.arm.com/help/topic/com.a...aqs/ka3947.html[/url]
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