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April 2013 GNU Toolchain Update

Deep Thought
Hi Guys,

  In this months new we have:

  * GCC now supports the x86_64-*-cygwin configuration option.

  * GCC has a new command line option: -fdiagnostics-color=[auto|never|always]

    This enables the use of colour (or color, if you prefer) in diagnostic messages.  The default is "never", and "auto" means only when sending the messages to a terminal.  The colours are defined by the environment variable GCC_COLORS.  Its value is a colon-separated list of capabilities and Select Graphic Rendition (SGR) substrings.  SGR commands are interpreted by the terminal, and support for any given SGR is dependent upon the terminal emulator being used.  The default settings if GCC_COLORS is not defined are:

    Where 01;31 is bold red, 01;35 is bold magenta, 01;36 is bold cyan, 01;32 is bold green and 01 is bold.  More details on this feature can be found in the GCC documentation.

  * The GCC ARM backend has a new feature enabled by the command line option: -mneon-for-64bits

    This enables the use of Neon instructions to handle scalar 64-bits operations. This is disabled by default even on targets which support the Neon instruction set since the cost of moving data from core registers into Neon registers is high.

  * Newlib has three new configuration options to help with small memory systems:


     This disables the write buffering normally used by the stream I/O functions.  It makes them less efficient in terms of calls to the system I/O functions, but it also significantly reduces the memory overhead of the newlib functions.

     The newlib implementation of the fseek* set of functions contains some code to optimize seeks where possible.  Although useful this code does take up space and on memory constrained systems it may be worth while disabling it.

    Newlib supports the C99 feature of "wide orientated" I/O streams.  If this support is not needed then this configuration option can save some space.



Deep Thought

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