[PATCH v4] Chapter-on-need-for-RTEMS-specific-cross-compiler

Gedare Bloom gedare at rtems.org
Fri Apr 3 15:47:43 UTC 2020


Hi Utkarsh,

This is almost there, really! The only  thing is that you maybe missed
or didn't understand a question from Sebastian, "What about using a
definition list instead of this hand crafted formatting?" Or any other
kind of list structure.

https://docutils.sourceforge.io/docs/user/rst/quickref.html#definition-lists

What do you think?

Gedare

On Fri, Apr 3, 2020 at 9:31 AM utkarsh.rai60 at gmail.com
<utkarsh.rai60 at gmail.com> wrote:
>
> ---
>  user/start/tools.rst | 33 +++++++++++++++++++++++++++++++++
>  1 file changed, 33 insertions(+)
>
> diff --git a/user/start/tools.rst b/user/start/tools.rst
> index c3f039b..9a3a93a 100644
> --- a/user/start/tools.rst
> +++ b/user/start/tools.rst
> @@ -3,6 +3,7 @@
>  .. Copyright (C) 2019 embedded brains GmbH
>  .. Copyright (C) 2019 Sebastian Huber
>  .. Copyright (C) 2020 Chris Johns
> +.. Copyright (C) 2020 Utkarsh Rai
>
>  .. _QuickStartTools:
>
> @@ -76,3 +77,35 @@ source code used.
>
>
>  Add ``--verbose`` to the GCC command for the the verbose version details.
> +
> +Need for RTEMS-Specific Cross-Compiler
> +---------------------------------------------------------
> +
> +New users are often confused as to why they cannot use their distribution's
> +cross-compiler for their target on rtems, e.g., the riscv64-linux-gnu or the
> +arm-none-eabi-gcc on RTEMS. Below mentioned are some of the reasons for using
> +the RTEMS cross-compiler.
> +
> + ``Correct configuration of Newlib -``
> +     Newlib is a C standard library implementation intended for use on embedded
> +     systems. Most of the POSIX and libc support for RTEMS is derived from
> +     Newlib. The RTEMS cross-compiler configures Newlib correctly for RTEMS.
> +
> + ``Threading in GCC support libraries -``
> +     Several threading packages in GCC such as Go threads (libgo), OpenMP
> +     (libgomp), and OpenACC need to be customized according to RTEMS. This is
> +     done by the RTEMS specific cross-compiler.
> +
> + ``Provide preprocessor define __rtems__ -``
> +     The  ``__rtems__``  preprocessor define is used to provide conditional code
> +     compilation in source files that are shared with other projects e.g. in
> +     Newlib or imported code from FreeBSD.
> +
> + ``Multilib variants to match the BSP -``
> +     RTEMS configures GCC to create separate runtime libraries for each
> +     supported instruction set, floating point unit, vector unit, word size
> +     (e.g. 32-bit and 64-bit), endianness, ABI, processor errata workarounds,
> +     and so on in the architecture. These libraries are termed as :ref:`Multilib
> +     <TargetArchitectures>` variants. Multilib variants to match the BSP are set
> +     by selecting a specific set of machine options using the RTEMS
> +     cross-compiler.
> --
> 2.17.1
>
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