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30e0d2a510
Add endian.h. This includes sys/endian.h and then adds extra defines
that glibc defines with double underscores for our
_{BIG,BYTE,LITTLE,PDP}_ENDIAN macros. We also define __FLOAT_WORD_ORDER
to be the same as _BYTE_ENDIAN since FreeBSD doesn't currently define
this, and the default with glibc is exactly this for our platforms.
Move common parts of endian.h and sys/endian.h into sys/_endian.h
to limit namespace pollution from endian.h
All this gives us good compatibility with Linux. There may be one or two
upstreams that haven't integrated the patches I tried to send up.
There are some minor differences:
o The extra glibc macros are not defined. These are all
controlled with either __ at the start, or only defined
when glibc is being built. We also don't define macros
that are used internally in glibc that would pollute
the namespace.
o For complete compatibility, this change must also be
paired with providing a glibc-compatible byteswap.h.
Sponsored by: Netflix
Reviewed by: mhorne, markj, jhb
Differential Revision: https://reviews.freebsd.org/D31962
44 lines
1.2 KiB
C
44 lines
1.2 KiB
C
/*-
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* Copyright (c) 2021 M. Warner Losh <imp@FreeBSD.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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/*
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* A mostly Linux/glibc-compatible endian.h
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*/
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#ifndef _ENDIAN_H_
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#define _ENDIAN_H_
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/*
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* FreeBSD's sys/_endian.h is very close to the interface provided on Linux by
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* glibc's endian.h.
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*/
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#include <sys/_endian.h>
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/*
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* glibc uses double underscore for these symbols. Define these unconditionally.
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* The compiler defines __BYTE_ORDER__ these days, so we don't do anything
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* with that since sys/endian.h defines _BYTE_ORDER based on it.
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*/
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#define __BIG_ENDIAN _BIG_ENDIAN
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#define __BYTE_ORDER _BYTE_ORDER
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#define __LITTLE_ENDIAN _LITTLE_ENDIAN
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#define __PDP_ENDIAN _PDP_ENDIAN
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/*
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* FreeBSD's sys/endian.h and machine/endian.h doesn't define a separate
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* byte order for floats. Use the host non-float byte order.
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*/
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#define __FLOAT_WORD_ORDER _BYTE_ORDER
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/*
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* We don't define BIG_ENDI, LITTLE_ENDI, HIGH_HALF and LOW_HALF macros that
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* glibc's endian.h defines since those appear to be internal to internal to
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* glibc. We also don't try to emulate the various helper macros that glibc
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* uses to limit namespace visibility.
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*/
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#endif /* _ENDIAN_H_ */
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