ARM Cortex-M Microcontroller startup files

[Jens Bauer via Digitalmars-d]

On Thursday, 30 April 2015 at 21:35:44 UTC, Mike wrote:
> On Thursday, 30 April 2015 at 21:08:22 UTC, Jens Bauer wrote:
>> Thus I would expect the hook to be somewhere in vfprintf ?
>
> As Timo said, eventually, what printf needs is the `write` 
> syscall.  The C library needs to be ported to the hardware in 
> question.  That requires implementing all the syscalls the the 
> C library needs:  `write` for printf, `sbrk` for malloc, etc... 
> (http://wiki.osdev.org/Porting_Newlib#newlib.2Flibc.2Fsys.2Fmyos.2Fsyscalls.c) 
> Sometimes the toolchain vendors provide this, sometimes the 
> programmer has to do it.

Uhm, in that case, why not supply a weakref dummy, eg. functions 
that can be overridden.
Thus stat, open, fstat, lseek, read, write, isatty, close, link 
and unlink just do nothing at all.
If the MCU has a file-system, then it can implement those as 
strong refs.
Same about gettimeofday, getpid, execve, fork, kill - Often 
there's only a single thread and no possibility for loading and 
executing a named program.
-So it should be fairly easy to change newlib 'requirements' to 
'optional'. :)

I feel like trying this out, perhaps when the new light comes. ;)