diff options
author | Joel Sherrill <joel@rtems.org> | 2023-07-03 10:32:53 -0500 |
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committer | Joel Sherrill <joel@rtems.org> | 2023-07-03 10:32:53 -0500 |
commit | 6264b14804bbe21f13d4691160b45e208286abaa (patch) | |
tree | aeb41fb50952bd3f3ef27b6fa42a97ff189e843e /cpukit | |
parent | 3d8fa0ef006a3a533e944f58e001cf79cd130842 (diff) |
Revert accidentally committed "Remove unused _IO_Relax"
Sebastian has agreed to move this out of score. I should have
removed this patch from my tree but accidentally committed it
with another patch.
Diffstat (limited to 'cpukit')
-rw-r--r-- | cpukit/include/rtems/score/io.h | 8 | ||||
-rw-r--r-- | cpukit/score/src/iorelax.c | 53 |
2 files changed, 61 insertions, 0 deletions
diff --git a/cpukit/include/rtems/score/io.h b/cpukit/include/rtems/score/io.h index 7fe69841e8..9cd401eb1d 100644 --- a/cpukit/include/rtems/score/io.h +++ b/cpukit/include/rtems/score/io.h @@ -133,6 +133,14 @@ int _IO_Base64url( int wordlen ); +/** + * @brief Issues a couple of no-operation instructions. + * + * This function may be used to burn a couple of processor cycles with minimum + * impact on the system bus. It may be used in busy wait loops. + */ +void _IO_Relax( void ); + /** @} */ #ifdef __cplusplus diff --git a/cpukit/score/src/iorelax.c b/cpukit/score/src/iorelax.c new file mode 100644 index 0000000000..1b155377a9 --- /dev/null +++ b/cpukit/score/src/iorelax.c @@ -0,0 +1,53 @@ +/* SPDX-License-Identifier: BSD-2-Clause */ + +/** + * @file + * + * @ingroup RTEMSScoreIO + * + * @brief This source file contains the implementation of _IO_Relax(). + */ + +/* + * Copyright (C) 2021 embedded brains GmbH & Co. KG + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + +#ifdef HAVE_CONFIG_H +#include "config.h" +#endif + +#include <rtems/score/io.h> +#include <rtems/score/cpuimpl.h> + +void _IO_Relax( void ) +{ + _CPU_Instruction_no_operation(); + _CPU_Instruction_no_operation(); + _CPU_Instruction_no_operation(); + _CPU_Instruction_no_operation(); + _CPU_Instruction_no_operation(); + _CPU_Instruction_no_operation(); + _CPU_Instruction_no_operation(); + _CPU_Instruction_no_operation(); +} |