How to place variables into a 2nd .bss / common section?
Tue Sep 3 09:23:00 GMT 2013
I'm working on an embedded system with a coldfire (m68k-elf) cpu.
The system has two different ram areas:
1. External DRAM (the main ram module)
2. Internal SRAM
The first and normal ".bss" section works just fine (see below).
To put global variables into the second section called
".bss_sram" I use the following macro:
#define SECTION_BSS_SRAM __attribute__((section(".bss_sram")))
Unfortunately, GCC generates assembler-code with the "@progbits"
which makes the linker mark the section as loadable and reserve
space in the executable (not necessary & unwanted):
"m68k-elf-objdump -h $EXECUTABLE" shows the problem:
5 .bss 01fac966 4000001c 00001700 0000401c 2**1
6 .bss_sram 00001094 80000000 80000000 00010000 2**11
CONTENTS, ALLOC, LOAD, DATA
I didn't find any options to tell GCC that this is a section with
"common" data, but instead found a "dirty workaround" to inject
the "@nobits" attribute into the assembly code:
Is this the only way to have a second common section or is there a
more beautiful way / option?
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