On 2007-04-11, [email protected] <[email protected]> wrote:
> The latest compiler supports the extended CPU; the problem is
> actually in the linker--I can't seem to make it recognise both
> chunks of code space (that below and above the vectors).
> Below is my original posting. I'm hoping someone knows the
> answer now.
Firstly, a CPU with a non-contiguous code space is just plain
f&*cked up.
Secondly, this is a question for the binutils mailing list.
FWIW the linker will "recognize" both segments just fine. The
problem is that it recognizes them as two separate memory
segments (hey, they _are_ two separate memory segments -- blame
TI for that). AFAIK, gnu ld doesn't support non-contiguous
memory segments. [If you want an authoritative answer, ask on
the binutils mailing list.] That means that the linker script
is going to have to tell the linker which modules go in which
"text" segment.
Supporting non-contiguous memory segments in a efficient manner
is an example of the classic "bin packing problem". It's a
combinatorial NP-hard problem. That's why a CPU with
non-contiguous code space is a bad idea.
>> I have been using msp430-gcc for several years now and have
>> just started using the MSP430FG4618 with the mspgcc-win32
>> 20070216 distribution. The ld script MEMORY configuration for
>> this chip looks like this:
>>
>> MEMORY
>> {
>> text (rx) : ORIGIN = 0x3100, LENGTH = 0xcec0
>> data (rwx) : ORIGIN = 0x1100, LENGTH = 0x2000
>> vectors (rw) : ORIGIN = 0xffc0 LENGTH = 64
>> bootloader(rx) : ORIGIN = 0x0c00, LENGTH = 1K
>> infomem(rx) : ORIGIN = 0x1000, LENGTH = 256
>> infomemnobits(rx) : ORIGIN = 0x1000, LENGTH = 256
>> }
>>
>> Note that the 64 kB of program flash starting at 0x10000 is
>> not included, so a 116 kB chip appears to only have 52 kB of
>> code space. I have tried adding another MEMORY definition as
>> follows:
>>
>> text2 (rx) : ORIGIN = 0x10000, LENGTH = 0x10000
>>
>> However, I cannot find any documentation on how to specify
>> multiple text segments in the SECTIONS definitions.
>> Currently, the .text section that is mapped with "> text" to
>> the program flash below the vectors. I have tried ">
>> text,text2" and "> text and > text2" but of course they are
>> not proper syntax. I have also tried a single MEMORY text
>> definition with two origins and two lengths, but the ld syntax
>> doesn't permit that, either.
>>
>> Can someone who groks ld enlighten me on how to gain access to
>> the all of the non-contiguous program flash in the new 'FG46xx
>> chips?
Again, why would one look to an MSP430 users mailing list for
questions on binutils linker script syntax?
--
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at is FLYING over FRANKFURT,
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