gcc/

	* cppbuiltin.c (define_builtin_macros_for_type_sizes): Define
	__BYTE_ORDER__, __ORDER_LITTLE_ENDIAN__, __ORDER_BIG_ENDIAN__, and
	__ORDER_PDP_ENDIAN__.
	* libgcc2.h (LIBGCC2_WORDS_BIG_ENDIAN): Delete.
	(struct DWstruct): Define based on __BYTE_ORDER__.
	* config/fixed-bit.h (LIBGCC2_WORDS_BIG_ENDIAN): Delete.
	(struct INTstruct): Define based on __BYTE_ORDER__.
	* config/dfp-bit.h (LIBGCC2_WORDS_BIG_ENDIAN): Delete.
	(LIBGCC2_FLOAT_WORDS_BIG_ENDIAN): Test __BYTE_ORDER__.
	* system.h (LIBGCC2_WORDS_BIG_ENDIAN): Poison identifier.
	* config/arc/arc.h (LIBGCC2_WORDS_BIG_ENDIAN): Delete.
	* config/arm/arm.h (LIBGCC2_WORDS_BIG_ENDIAN): Delete.
	* config/ia64/ia64.h (LIBGCC2_WORDS_BIG_ENDIAN): Delete.
	* config/iq2000/iq2000.h (LIBGCC2_WORDS_BIG_ENDIAN): Delete.
	* config/lm32/lm32.h (LIBGCC2_WORDS_BIG_ENDIAN): Delete.
	* config/m32r/m32r.h (LIBGCC2_WORDS_BIG_ENDIAN): Delete.
	* config/mcore/mcore.h (LIBGCC2_WORDS_BIG_ENDIAN): Delete.
	* config/mep/mep.h (LIBGCC2_WORDS_BIG_ENDIAN): Delete.
	* config/mips/mips.h (LIBGCC2_WORDS_BIG_ENDIAN): Delete.
	* config/rs6000/sysv4.h (LIBGCC2_WORDS_BIG_ENDIAN): Delete.
	* config/rx/rx.h (LIBGCC2_WORDS_BIG_ENDIAN): Delete.
	* config/score/score.h (LIBGCC2_WORDS_BIG_ENDIAN): Delete.
	* config/sh/sh.h (LIBGCC2_WORDS_BIG_ENDIAN): Delete.
	* config/sparc/sparc.h (LIBGCC2_WORDS_BIG_ENDIAN): Delete.
	* config/xtensa/xtensa.h (LIBGCC2_WORDS_BIG_ENDIAN): Delete.
	* doc/tm.texi.in (LIBGCC2_WORDS_BIG_ENDIAN): Delete.
	* doc/tm.texi: Regenerate.
	* doc/cpp.texi (__BYTE_ORDER__, __ORDER_LITTLE_ENDIAN__): Document.
	(__ORDER_BIG_ENDIAN__, __ORDER_PDP_ENDIAN__): Likewise.

libdecnumber/
	* dconfig.h (LIBGCC2_WORDS_BIG_ENDIAN): Delete.
	(LIBGCC2_FLOAT_WORDS_BIG_ENDIAN): Test __BYTE_ORDER__.

libgcc/
	* config/libbid/bid_gcc_intrinsics.h (LIBGCC2_WORDS_BIG_ENDIAN):
	Delete.
	(LIBGCC2_FLOAT_WORDS_BIG_ENDIAN): Test __BYTE_ORDER__.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@165881 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 24 insertions, 0 deletions

diff --git a/gcc/doc/cpp.texi b/gcc/doc/cpp.texi
index a580e6108c8..ddcf81467f6 100644
--- a/gcc/doc/cpp.texi
+++ b/gcc/doc/cpp.texi
@@ -2265,6 +2265,30 @@ Defined to the number of bytes of the C standard data types: @code{int},
 @code{double}, @code{long double}, @code{size_t}, @code{wchar_t}, @code{wint_t}
 and @code{ptrdiff_t}.
 
+@item __BYTE_ORDER__
+@itemx __ORDER_LITTLE_ENDIAN__
+@itemx __ORDER_BIG_ENDIAN__
+@itemx __ORDER_PDP_ENDIAN__
+@code{__BYTE_ORDER__} is defined to one of the values
+@code{__ORDER_LITTLE_ENDIAN__}, @code{__ORDER_BIG_ENDIAN__}, or
+@code{__ORDER_PDP_ENDIAN__} to reflect the layout of multi-byte and
+multi-word quantities in memory.  If @code{__BYTE_ORDER__} is equal to
+@code{__ORDER_LITTLE_ENDIAN__} or @code{__ORDER_BIG_ENDIAN__}, then
+multi-byte and multi-word quantities are laid out identically: the
+byte (word) at the lowest address is the least significant or most
+significant byte (word) of the quantity, respectively.  If
+@code{__BYTE_ORDER__} is equal to @code{__ORDER_PDP_ENDIAN__}, then
+bytes in 16-bit words are laid out in a little-endian fashion, whereas
+the 16-bit subwords of a 32-bit quantity are laid out in big-endian
+fashion.
+
+You should use these macros for testing like this:
+
+@smallexample
+/* @r{Test for a little-endian machine} */
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+@end smallexample
+
 @item __DEPRECATED
 This macro is defined, with value 1, when compiling a C++ source file
 with warnings about deprecated constructs enabled.  These warnings are