mirror of
https://github.com/zephyrproject-rtos/zephyr
synced 2025-09-02 17:33:00 +00:00
4a470114fa
Consistently place C++ use of extern "C" after all include directives, within the negative branch of _ASMLANGUAGE if used. Remove extern "C" support from files that don't declare objects or functions. In arch/arc/arch.h the extern "C" in the including context is left active during an include to avoid more complex restructuring. Background from issue #17997: Declarations that use C linkage should be placed within extern "C" so the language linkage is correct when the header is included by a C++ compiler. Similarly #include directives should be outside the extern "C" to ensure the language-specific default linkage is applied to any declarations provided by the included header. See: https://en.cppreference.com/w/cpp/language/language_linkage Signed-off-by: Peter Bigot <peter.bigot@nordicsemi.no>
91 lines
1.8 KiB
C
91 lines
1.8 KiB
C
/*
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* Copyright (c) 2014 Wind River Systems, Inc.
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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/**
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* @file
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* @brief ARCv2 public kernel find-first-set interface
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*
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* ARC-specific kernel ffs interface. Included by arc/arch.h.
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*/
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#ifndef ZEPHYR_INCLUDE_ARCH_ARC_V2_FFS_H_
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#define ZEPHYR_INCLUDE_ARCH_ARC_V2_FFS_H_
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#ifndef _ASMLANGUAGE
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#include <zephyr/types.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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/**
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*
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* @brief find most significant bit set in a 32-bit word
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*
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* This routine finds the first bit set starting from the most significant bit
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* in the argument passed in and returns the index of that bit. Bits are
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* numbered starting at 1 from the least significant bit. A return value of
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* zero indicates that the value passed is zero.
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*
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* @return most significant bit set, 0 if @a op is 0
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*/
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#if defined(__GNUC__)
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static ALWAYS_INLINE unsigned int find_msb_set(u32_t op)
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{
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unsigned int bit;
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__asm__ volatile(
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/* see explanation in ffs.S */
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"fls.f %0, %1;\n\t"
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"add.nz %0, %0, 1;\n\t"
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: "=r"(bit)
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: "r"(op));
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return bit;
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}
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#endif
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/**
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*
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* @brief find least significant bit set in a 32-bit word
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*
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* This routine finds the first bit set starting from the least significant bit
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* in the argument passed in and returns the index of that bit. Bits are
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* numbered starting at 1 from the least significant bit. A return value of
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* zero indicates that the value passed is zero.
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*
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* @return least significant bit set, 0 if @a op is 0
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*/
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#if defined(__GNUC__)
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static ALWAYS_INLINE unsigned int find_lsb_set(u32_t op)
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{
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unsigned int bit;
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__asm__ volatile(
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/* see explanation in ffs.S */
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"ffs.f %0, %1;\n\t"
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"add.nz %0, %0, 1;\n\t"
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"mov.z %0, 0;\n\t"
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: "=&r"(bit)
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: "r"(op));
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return bit;
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}
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#endif
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#ifdef __cplusplus
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}
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#endif
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#endif /* _ASMLANGUAGE */
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#endif /* ZEPHYR_INCLUDE_ARCH_ARC_V2_FFS_H_ */
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