Hi, all

I 'm very newbie in bare metal application, cross-compiler.

As I know, for bare-metal application,
I have to use the Openrisc GNU tool chain with newlib.
Is it correct?

If it is correct, I have a question about C standard library with newlib.

I made a simple code for test.

-------------------------
int main ( int argc, char **argv ){

double *A = (double*)calloc( 1, sizeof(double) );
A[0] = 1;
}
-------------------------

But the linker "or32-elf-ld" showed an error message.
-------------------------
or32-elf-ld init.o test.o -o eprom.elf -T or32.ld -Map eprom.map -L /opt/openrisc/or32-elf/lib/ -lc
/opt/openrisc/or32-elf/lib//libc.a(lib_a-sbrkr.o): In function `_sbrk_r':
/opt/gnu-stable/bd-elf/or32-elf/newlib/libc/reent/../../../../../unisrc/newlib/libc/reent/sbrkr.c:60: undefined reference to `_sbrk'
-------------------------

With newlib, not allowed using C standard library?
What should I do to use C standard library?

Actually I'd like to use many functions in C/C++ library.
But I think, I am missing something that very very basic fact...

Please let me know that I missed thing...

I'm sorry to bother all.

Thank you

Hi scan15g

If you want to link with C libraries, use gcc or g++ to do the linking, not ld. It will ensure all the correct libraries, CRT files and so on are applied. In your case start with:

or32-elf-gcc init.o test.o -o eprom.elf

If you want to pass funny linker scripts and maps to the linker, use the GCC options (-Wl etc) to pass options to the linker.

HTH,

Jeremy

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Hi Jeremy,

Thanks for the reply, the problem is simply solved.

Again, I'm sorry, but I just have one more question about memory setting, for example memory size.

It is good, or32-elf-gcc or g++ automatically linking and making the memory map,
but I have found that I could not specify the start of the stack address.

So in modelsim simulation, I have to expand the memory size can cover the current memory size is the same as start of stack address.

How can I specify the memory size?
Please give me a hint to solve my worries.

Thank you,

Regards,
scan15g

Hi scan15g

IIRC the current implementation of newlib imposes a fixed size on the memory with which it will work, since that is what most engineers want. The previous implementation determined the available memory and set the end of stack to that point.

I believe to fix this you'll need to find the location in newlib libgloss where the stack size is specified and change it (it will be in libgloss/or32) before rebuilding the tool chain.

I think Julius Baxter is currently the maintainer of newlib, and may be able to give more information. You could try the mailing lists, or the IRC forum (#openrisc on freenode.net).

HTH,

Jeremy

Hi, Jeremy

Thank you for your comment,
I could find the instruction to set the memory size etc. for openrisc enviorment setup at follow link.

http://opencores.org/or1k/Newlib#Board_support_details

Now, I can cross-compile some C/C++ source code with Openrisc Tool Chain
and execute(actually simulation) the compiled and linked binary with openrisc 1200.

But, I'm afraid that I use the library(function) which is not supported by current Openrisc Tool Chain.

So I would like to know the libraries that current tool chain can be supported.

For newlib, I could get the documentation in "http://sourceware.org/newlib/"
But newlib can be supported only C library.

As I know Openrisc Tool Chain can support not only C library but also C++ library.
I wouild like to get the documentation like newlib web page.

Is there any documentation about supported library(function) list?

Thanks for your support.

Best Regards,
scan15g

Hi scan15g

C++ is supported just fine by newlib. The standard C++ library (part of GCC) is built on top of newlib. It is a standard library, so documented elsewhere, for example, http://www.cplusplus.com/reference/.

Of course you won't get any OS features that are not supported by the underlying newlib implementation. For example bare metal OpenRISC newlib only supports a single thread. But to fix that you'll need some sort of operating system. eCos, FreeRTOS and Linux are all available for OpenRISC.

HTH

Jeremy

Hi, Jeremy

Thank you very much,
More detailed thing, I'll look on the web.

Thank you for letting me know a lot of things.
I'll do my best to do my work.

Thank you,

Best Regards
scan15g