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+><TITLE
+>Modifying the Memory Layout</TITLE
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+>eCos User Guide</TH
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+>Chapter 28. Manual Configuration</TD
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+><DIV
+CLASS="SECT1"
+><H1
+CLASS="SECT1"
+><A
+NAME="MODIFYING-THE-MEMORY-LAYOUT">Modifying the Memory Layout</H1
+><P
+>Each <SPAN
+CLASS="PRODUCTNAME"
+>eCos</SPAN
+> platform package is supplied with linker script
+fragments which describe the location of memory regions on the evaluation
+board and the location of memory sections within these regions.
+The correct linker script fragment is selected and included in the
+<SPAN
+CLASS="PRODUCTNAME"
+>eCos</SPAN
+> linker script <TT
+CLASS="FILENAME"
+>target.ld</TT
+> when
+<SPAN
+CLASS="PRODUCTNAME"
+>eCos</SPAN
+> is built.</P
+><P
+>It is not necessary to modify the default memory
+layouts in order to start development with <SPAN
+CLASS="PRODUCTNAME"
+>eCos</SPAN
+>. However, it will
+be necessary to edit a linker script fragment when the memory map
+of the evaluation board is changed. For example, if additional memory
+is added, the linker must be notified that the new memory is available
+for use. As a minimum, this would involve modifying the length of
+the corresponding memory region. Where the available memory is non-contiguous,
+it may be necessary to declare a new memory region and reassign
+certain linker output sections to the new region.</P
+><P
+>Linker script fragments and memory layout header files should
+be edited within the <SPAN
+CLASS="PRODUCTNAME"
+>eCos</SPAN
+> install tree. They are
+located at <TT
+CLASS="FILENAME"
+>include/pkgconf/mlt_*.*</TT
+>.
+Where multiple start-up types are in use, it will be necessary to
+edit multiple linker script fragments and header files. The information
+provided in the header file and the corresponding linker script
+fragment must always match. A typical linker script fragment is
+shown below:</P
+><DIV
+CLASS="EXAMPLE"
+><A
+NAME="AEN2992"><P
+><B
+>Example 28-1. <SPAN
+CLASS="PRODUCTNAME"
+>eCos</SPAN
+> linker script fragment</B
+></P
+><TABLE
+BORDER="5"
+BGCOLOR="#E0E0F0"
+WIDTH="70%"
+><TR
+><TD
+><PRE
+CLASS="PROGRAMLISTING"
+>MEMORY
+{
+ rom : ORIGIN = 0x40000000, LENGTH = 0x80000
+ ram : ORIGIN = 0x48000000, LENGTH = 0x200000
+}
+
+SECTIONS
+{
+ SECTIONS_BEGIN
+ SECTION_rom_vectors (rom, 0x40000000, LMA_EQ_VMA)
+ SECTION_text (rom, ALIGN (0x1), LMA_EQ_VMA)
+ SECTION_fini (rom, ALIGN (0x1), LMA_EQ_VMA)
+ SECTION_rodata (rom, ALIGN (0x1), LMA_EQ_VMA)
+ SECTION_rodata1 (rom, ALIGN (0x1), LMA_EQ_VMA)
+ SECTION_fixup (rom, ALIGN (0x1), LMA_EQ_VMA)
+ SECTION_gcc_except_table (rom, ALIGN (0x1), LMA_EQ_VMA)
+ SECTION_data (ram, 0x48000000, FOLLOWING (.gcc_except_table))
+ SECTION_bss (ram, ALIGN (0x4), LMA_EQ_VMA)
+ SECTIONS_END
+}</PRE
+></TD
+></TR
+></TABLE
+></DIV
+><P
+>The file consists of two blocks, the <TT
+CLASS="LITERAL"
+>MEMORY</TT
+> block
+contains lines describing the address (<TT
+CLASS="LITERAL"
+>ORIGIN</TT
+>)
+and the size (<TT
+CLASS="LITERAL"
+>LENGTH</TT
+>) of each memory
+region. The <TT
+CLASS="LITERAL"
+>MEMORY</TT
+> block is followed
+by the <TT
+CLASS="LITERAL"
+>SECTIONS</TT
+> block which contains
+lines describing each of the linker output sections. Each section
+is represented by a macro call. The arguments of these macros are
+ordered as follows: </P
+><P
+></P
+><OL
+TYPE="1"
+><LI
+><P
+>The memory region in which the section will finally
+ reside.</P
+></LI
+><LI
+><P
+>The final address (
+<TT
+CLASS="LITERAL"
+>VMA</TT
+>
+) of the section. This is expressed using one of the following forms:</P
+><P
+></P
+><DIV
+CLASS="VARIABLELIST"
+><DL
+><DT
+><SPAN
+CLASS="emphasis"
+><I
+CLASS="EMPHASIS"
+>n</I
+></SPAN
+></DT
+><DD
+><P
+>at the absolute address specified by the
+ unsigned integer <SPAN
+CLASS="emphasis"
+><I
+CLASS="EMPHASIS"
+>n</I
+></SPAN
+></P
+></DD
+><DT
+>ALIGN (<SPAN
+CLASS="emphasis"
+><I
+CLASS="EMPHASIS"
+>n</I
+></SPAN
+>)</DT
+><DD
+><P
+>following the final location of the previous section
+ with alignment to the next <SPAN
+CLASS="emphasis"
+><I
+CLASS="EMPHASIS"
+>n</I
+></SPAN
+>-byte
+ boundary</P
+></DD
+></DL
+></DIV
+></LI
+><LI
+><P
+>The initial address (<TT
+CLASS="LITERAL"
+>LMA</TT
+>)
+ of the section. This is expressed using one of the
+ following forms:</P
+><P
+></P
+><DIV
+CLASS="VARIABLELIST"
+><DL
+><DT
+>LMA_EQ_VMA</DT
+><DD
+><P
+>the <TT
+CLASS="LITERAL"
+>LMA</TT
+>
+ equals the <TT
+CLASS="LITERAL"
+>VMA</TT
+> (no relocation)</P
+></DD
+><DT
+>AT (<SPAN
+CLASS="emphasis"
+><I
+CLASS="EMPHASIS"
+>n</I
+></SPAN
+>)</DT
+><DD
+><P
+>at the absolute address specified by the
+ unsigned integer <SPAN
+CLASS="emphasis"
+><I
+CLASS="EMPHASIS"
+>n</I
+></SPAN
+></P
+></DD
+><DT
+>FOLLOWING (.<SPAN
+CLASS="emphasis"
+><I
+CLASS="EMPHASIS"
+>name</I
+></SPAN
+>)</DT
+><DD
+><P
+>following the initial location of section
+ <SPAN
+CLASS="emphasis"
+><I
+CLASS="EMPHASIS"
+>name</I
+></SPAN
+></P
+></DD
+></DL
+></DIV
+></LI
+></OL
+><P
+>In order to maintain compatibility with linker script
+ fragments and header files exported by the
+ <SPAN
+CLASS="PRODUCTNAME"
+>eCos</SPAN
+> <SPAN
+CLASS="APPLICATION"
+>Configuration Tool</SPAN
+>, the use
+ of other expressions within these files is not
+ recommended.</P
+><P
+>Note that the names of the linker output sections will vary
+between target architectures. A description of these sections can
+be found in the specific <SPAN
+CLASS="PRODUCTNAME"
+>GCC</SPAN
+> documentation for
+your architecture.</P
+></DIV
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