[ECOS] Is using the newlib optimised routines in side the Dsr (suppose if the dsr calls for every 10ms space)

[ECOS] Is using the newlib optimised routines in side the Dsr (suppose if the dsr calls for every 10ms space)

[srinivas naga vutukuri]

Dear All,

       I just want to know that is there any problem of using the
newlib optimised C library routines in side the Dsr (suppose if the
Dsr calls for every 10ms space).

      I am using xscale (ixp425) tool chain, and newlib is part of the
tool chain. So obviously this piece of code might have been used when
i call memset inside my application code of eCos

http://sourceware.org/cgi-bin/cvsweb.cgi/src/newlib/libc/machine/xscale/memset.c?rev=1.3&content-type=text/x-cvsweb-markup&cvsroot=src

     What could be the possible difference if i use the direct coding
the routine of

void *
memset(void *sp1, int c, size_t n)
{

      if (n != 0) {
        unsigned char *sp = sp1;
        do {
                *sp++ = (unsigned char)c;
            } while (--n != 0);
      }
     return (sp1);
}


best regards,
srinivas.

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[ECOS] Re: Is using the newlib optimised routines in side the Dsr (suppose if the dsr calls for every 10ms space)

[Sergei Organov]

"srinivas naga vutukuri" <srinivas.vutukuri@gmail.com> writes:

> Dear All,
>
>        I just want to know that is there any problem of using the
> newlib optimised C library routines in side the Dsr (suppose if the
> Dsr calls for every 10ms space).
>
>       I am using xscale (ixp425) tool chain, and newlib is part of the
> tool chain. So obviously this piece of code might have been used when
> i call memset inside my application code of eCos

When you just use memset in eCos application, most probably it will be
taken not from newlib, but from eCos own C library. You can easily check
what is linked by searching for 'memset' in the map file generated by the
linker. In my case 'memset' is taken from
ecos/install/lib/libtarget.a(infra_memset.o).

Anyway, there should be no harm using 'memset' from either newlib or
eCos from DSR, unless there are some xscale-specific issues I'm not
aware of.

-- 
Sergei.


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Re: [ECOS] Re: Is using the newlib optimised routines in side the Dsr (suppose if the dsr calls for every 10ms space)

[Andrew Lunn]

On Fri, Oct 05, 2007 at 12:53:32PM +0400, Sergei Organov wrote:
> "srinivas naga vutukuri" <srinivas.vutukuri@gmail.com> writes:
> 
> > Dear All,
> >
> >        I just want to know that is there any problem of using the
> > newlib optimised C library routines in side the Dsr (suppose if the
> > Dsr calls for every 10ms space).
> >
> >       I am using xscale (ixp425) tool chain, and newlib is part of the
> > tool chain. So obviously this piece of code might have been used when
> > i call memset inside my application code of eCos
> 
> When you just use memset in eCos application, most probably it will be
> taken not from newlib, but from eCos own C library. You can easily check
> what is linked by searching for 'memset' in the map file generated by the
> linker. In my case 'memset' is taken from
> ecos/install/lib/libtarget.a(infra_memset.o).

The newlib library is not used for anything in eCos. My understanding
is that newlib is just there in order to get the toolchain to compile.

One other comment is that sometimes the compiler will use its builtin
implementations of simple functions like memset, etc. This is
especially true when it has fixed parameters, eg memset(&foo, 0,
4). The compile will just use a couple of machine instructions, rather
than making a function call.

A general rule of thumb for DSR. Don't call any functions which could
block. string functions should be safe.

       Andrew

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Re: [ECOS] Re: Is using the newlib optimised routines in side the Dsr (suppose if the dsr calls for every 10ms space)

[Gary Thomas]

Andrew Lunn wrote:
> On Fri, Oct 05, 2007 at 12:53:32PM +0400, Sergei Organov wrote:
>> "srinivas naga vutukuri" <srinivas.vutukuri@gmail.com> writes:
>>
>>> Dear All,
>>>
>>>        I just want to know that is there any problem of using the
>>> newlib optimised C library routines in side the Dsr (suppose if the
>>> Dsr calls for every 10ms space).
>>>
>>>       I am using xscale (ixp425) tool chain, and newlib is part of the
>>> tool chain. So obviously this piece of code might have been used when
>>> i call memset inside my application code of eCos
>> When you just use memset in eCos application, most probably it will be
>> taken not from newlib, but from eCos own C library. You can easily check
>> what is linked by searching for 'memset' in the map file generated by the
>> linker. In my case 'memset' is taken from
>> ecos/install/lib/libtarget.a(infra_memset.o).
> 
> The newlib library is not used for anything in eCos. My understanding
> is that newlib is just there in order to get the toolchain to compile.

Correct, although RedBoot *can* be configured to support stand-alone
programs built using newlib only (no eCos code involved).  Normal eCos
applications don't use newlib in any way.

> One other comment is that sometimes the compiler will use its builtin
> implementations of simple functions like memset, etc. This is
> especially true when it has fixed parameters, eg memset(&foo, 0,
> 4). The compile will just use a couple of machine instructions, rather
> than making a function call.

True, but this does depend on the hardware (architecture) - GCC does
things differently on each.

Effort was made to make sure that the eCos source tree itself always
has its own implementation of any routines used by the compiler.  This
was done so that we could control all aspects of the resulting code.

> A general rule of thumb for DSR. Don't call any functions which could
> block. string functions should be safe.
> 
>        Andrew
> 


-- 
------------------------------------------------------------
Gary Thomas                 |  Consulting for the
MLB Associates              |    Embedded world
------------------------------------------------------------

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[ECOS] Re: Is using the newlib optimised routines in side the Dsr (suppose if the dsr calls for every 10ms space)

[Grant Edwards]

On 2007-10-05, Andrew Lunn <andrew@lunn.ch> wrote:

> The newlib library is not used for anything in eCos. My understanding
> is that newlib is just there in order to get the toolchain to compile.

That's something I've never understood.  I use gcc for a
half-dozen non-eCos embedded targets, and never had to use
newlib to get the toolchains to compile.  They've always
compiled fine without it.

What is it about eCos that requires newlib?

-- 
Grant Edwards                   grante             Yow! As President I have
                                  at               to go vacuum my coin
                               visi.com            collection!


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[ECOS] Re: Is using the newlib optimised routines in side the Dsr (suppose if the dsr calls for every 10ms space)

[Daniel Néri]

Grant Edwards <grante@visi.com> writes:

> What is it about eCos that requires newlib?

Nothing, in my experience. At least w/ recent versions of GCC.


Regards,
-- 
Daniel Néri <daniel.neri@sigicom.se>
Sigicom AB, Stockholm, Sweden


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[ECOS] Re: Is using the newlib optimised routines in side the Dsr (suppose if the dsr calls for every 10ms space)

[Sergei Organov]

Grant Edwards <grante@visi.com> writes:

> On 2007-10-05, Andrew Lunn <andrew@lunn.ch> wrote:
>
>> The newlib library is not used for anything in eCos. My understanding
>> is that newlib is just there in order to get the toolchain to compile.
>
> That's something I've never understood.  I use gcc for a
> half-dozen non-eCos embedded targets, and never had to use
> newlib to get the toolchains to compile.  They've always
> compiled fine without it.

My experience is opposite. I never succeeded to get cross-compiler for
embedded target without a link to newlib tree from withing gcc tree, and
then newlib is compiled and installed along with gcc. Maybe it's fixed
in recent GCCs though.

-- Sergei.


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