smaller ramsize for newlib-nano builds

[Jaap de Wolff]

Hello,

 

I am working with embedded systems with have very limited ram resources.

As known current version of the newlib-nano build uses 364 bytes of ram for
__global_locale

 

When configured with 

CFLAGS_FOR_TARGET='-Os -ffunction-sections -fdata-sections
-D_NANO_NO_GLOBAL_LOCALE'

and the following modification below I was able to move __global_locale to
rom.

I realize that MB_CAPABLE must be off for this modification, but are there
other implications?

 

Jaap

 

====================================== start of modification
=======================================================

diff -Nuar newlib.nor/newlib/libc/locale/locale.c
newlib/newlib/libc/locale/locale.c

--- newlib.nor/newlib/libc/locale/locale.c              2017-03-14
21:30:33.000000000 +0100

+++ newlib/newlib/libc/locale/locale.c   2018-01-31 13:32:25.580898000 +0100

@@ -255,7 +255,11 @@

};

#endif /* _MB_CAPABLE */

+#ifdef _NANO_CONST_GLOBAL_LOCALE

+const struct __locale_t __global_locale =

+#else

struct __locale_t __global_locale =

+#endif

{

   { "C", "C", DEFAULT_LOCALE, "C", "C", "C", "C", },

#ifdef __CYGWIN__

diff -Nuar newlib.nor/newlib/libc/locale/setlocale.h
newlib/newlib/libc/locale/setlocale.h

--- newlib.nor/newlib/libc/locale/setlocale.h       2016-11-28
19:32:45.000000000 +0100

+++ newlib/newlib/libc/locale/setlocale.h            2018-01-31
14:31:39.760898000 +0100

@@ -206,10 +206,18 @@

 /* In POSIX terms the global locale is the process-wide locale.  Use this

    function to always refer to the global locale. */

+#ifdef _NANO_CONST_GLOBAL_LOCALE

+_ELIDABLE_INLINE const struct __locale_t *

+#else

_ELIDABLE_INLINE struct __locale_t *

+#endif

__get_global_locale ()

{

+#ifdef _NANO_CONST_GLOBAL_LOCALE

+  extern const struct __locale_t __global_locale;

+#else

   extern struct __locale_t __global_locale;

+#endif

   return &__global_locale;

}

 

====================================== end of modification
=======================================================