Specifications

312 www.xilinx.com Embedded System Tools Guide (EDK 6.2i)
1-800-255-7778 UG111 (v1.4) January 30, 2004
Chapter 22: Address Management
R
section is accessed using absolute addresses. This section has the w (read-write) and the i
(initialized) flags.
.sdata
This section contains small read-write data of a size less than 8 bytes (default). The size of
the data going into this section can be changed with an mb-gcc -G option. All data in this
section is accessed with reference to the read-write small data anchor. This ensures that all
data in the .sdata section uses a single instruction. (A preceding imm instruction will never
be necessary). This section has the w (read-write) and the i (initialized) flags.
.sbss
This section contains small un-initialized data of a size less than 8 bytes (default). The size
of the data going into this section can be changed with an mb-gcc -G option. This section
has the w (read-write) flag.
.bss
This section contains un-initialized data of a size more than 8 bytes (default). The size of
the data going into this section can be changed with an mb-gcc -G option. All data in this
section is accessed using absolute addresses. The stack and the heap are also allocated to
this section. This section has the w (read-write) flag.
The linker script describes the mapping between all the sections in all the input object files,
and the output executable file.
If your address map specifies that the LMB, OPB and External Memory occupy
contiguous areas of memory, you can use the default (built-in) linker script to generate
your executable. This is done by invoking mb-gcc as follows:
mb-gcc file1.c file2.c
Figure 22-3: Sectional Layout of an Object or Executable File
Text Section
Sectional Layout of an object or an Executable File
Read-Only Data Section
Small Read-Only Data Section
Read-Write Data Section
Small Read-Write Data Section
Small Uninitialized Data Section
Uninitialized Data Section
.text
.rodata
.sdata2
.data
.sdata
.sbss
.bss
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