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cf66bb93e0
Since GCC 4.4, there have been __builtin_bswap32() and __builtin_bswap16() intrinsics. A __builtin_bswap16() came a little later (4.6 for PowerPC, 48 for other platforms). By using these instead of the inline assembler that most architectures have in their __arch_swabXX() macros, we let the compiler see what's actually happening. The resulting code should be at least as good, and much *better* in the cases where it can be combined with a nearby load or store, using a load-and-byteswap or store-and-byteswap instruction (e.g. lwbrx/stwbrx on PowerPC, movbe on Atom). When GCC is sufficiently recent *and* the architecture opts in to using the intrinsics by setting CONFIG_ARCH_USE_BUILTIN_BSWAP, they will be used in preference to the __arch_swabXX() macros. An architecture which does not set ARCH_USE_BUILTIN_BSWAP will continue to use its own hand-crafted macros. Signed-off-by: David Woodhouse <David.Woodhouse@intel.com> Acked-by: H. Peter Anvin <hpa@linux.intel.com>
39 lines
901 B
C
39 lines
901 B
C
#ifndef __LINUX_COMPILER_H
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#error "Please don't include <linux/compiler-intel.h> directly, include <linux/compiler.h> instead."
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#endif
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#ifdef __ECC
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/* Some compiler specific definitions are overwritten here
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* for Intel ECC compiler
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*/
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#include <asm/intrinsics.h>
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/* Intel ECC compiler doesn't support gcc specific asm stmts.
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* It uses intrinsics to do the equivalent things.
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*/
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#undef barrier
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#undef RELOC_HIDE
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#define barrier() __memory_barrier()
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#define RELOC_HIDE(ptr, off) \
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({ unsigned long __ptr; \
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__ptr = (unsigned long) (ptr); \
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(typeof(ptr)) (__ptr + (off)); })
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/* Intel ECC compiler doesn't support __builtin_types_compatible_p() */
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#define __must_be_array(a) 0
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#endif
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#define uninitialized_var(x) x
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#ifndef __HAVE_BUILTIN_BSWAP16__
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/* icc has this, but it's called _bswap16 */
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#define __HAVE_BUILTIN_BSWAP16__
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#define __builtin_bswap16 _bswap16
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#endif
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