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How is . = 0xADDR different from using MEMORY?
- From: Rick Mann <rmann at latencyzero dot com>
- To: binutils <binutils at sourceware dot org>
- Date: Thu, 1 Nov 2007 18:03:22 -0700
- Subject: How is . = 0xADDR different from using MEMORY?
Hi. I've been trying to move from using . = 0xABCD1234 in my linker
script to put sections in the right place, to using the MEMORY
command. But it's not behaving as I would expect.
I have the following sections in the (working) script (there are more,
but this should serve for the example):
SECTIONS
{
. = 0x80008000;
. = ALIGN(4);
.text :
{
obj/start.o(.text);
src/Interrupts.o(.text);
. = ALIGN(4);
__gVectorsStart = .;
KEEP (obj/vectors.o(.text));
__gVectorsEnd = .;
. = ALIGN(4);
*(.text);
}
. = ALIGN(4);
.bss :
{
__bss_start = .;
__bss_start__ = .;
/* first the real BSS data */
*(.bss)
*(COMMON)
/* and next the stack */
. = ALIGN(4);
/* allocate an 8kB stack */
. = . + 8 * 1024;
__stack_end = .;
__bss_end = .;
__bss_end__ = .;
}
. = ALIGN(1024 * 1024);
.frameBuffer :
{
__gFrameBufferSectionStart = .;
*(.frameBuffer)
__gFrameBufferSectionEnd = .;
}
. = ALIGN(16 * 1024 * 1024);
.mmuTables :
{
*(.mmuTables)
}
}
If I do this, I get what I would expect: a 16MB+-sized binary (because
of the 16MB alignment of .mmuTables). If instead, I add this:
MEMORY
{
dram (wx) : org = 0x80008000, len = 128M
vectors (wx) : org = 0x00000000, len = 1M
theCaddo (wx) : org = 0x5C000000, len = 32K
bootRomData (rw) : org = 0x5C008000, len = 48K
sram (wx) : org = 0x5C014000, len = 688K
rom (rw) : org = 0x5E000000, len = 64K
monitor (rwx) : org = 0x80000000, len = 32K
}
and append ">dram" to each section above, and remove the . =
0x80008000 at the top, I get a 4 MB+ binary.
This is all in an effort to place my sections closer together in the
image, but I'm not there yet. I just wanted to get the memory map part
working correctly. Any idea what's going on?
TIA,
Rick