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Diffstat (limited to 'nuttx/sched/sched_yield.c')
-rw-r--r-- | nuttx/sched/sched_yield.c | 101 |
1 files changed, 101 insertions, 0 deletions
diff --git a/nuttx/sched/sched_yield.c b/nuttx/sched/sched_yield.c new file mode 100644 index 000000000..b2e6493d0 --- /dev/null +++ b/nuttx/sched/sched_yield.c @@ -0,0 +1,101 @@ +/**************************************************************************** + * sched/sched_yield.c + * + * Copyright (C) 2007, 2009 Gregory Nutt. All rights reserved. + * Author: Gregory Nutt <gnutt@nuttx.org> + * + * 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. + * 3. Neither the name NuttX nor the names of its contributors may be + * used to endorse or promote products derived from this software + * without specific prior written permission. + * + * 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. + * + ****************************************************************************/ + +/**************************************************************************** + * Included Files + ****************************************************************************/ + +#include <nuttx/config.h> + +#include <nuttx/arch.h> + +#include "os_internal.h" + +/**************************************************************************** + * Definitions + ****************************************************************************/ + +/**************************************************************************** + * Private Type Declarations + ****************************************************************************/ + +/**************************************************************************** + * Global Variables + ****************************************************************************/ + +/**************************************************************************** + * Private Variables + ****************************************************************************/ + +/**************************************************************************** + * Private Function Prototypes + ****************************************************************************/ + +/**************************************************************************** + * Private Functions + ****************************************************************************/ + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: sched_yield + * + * Description: + * This function forces the calling task to give up the CPU (only to other + * tasks at the same priority). + * + * Inputs: + * None + * + * Return Value: + * 0 (OK) or -1 (ERROR) (errno is not set) + * + * Assumptions: + * + ****************************************************************************/ + +int sched_yield(void) +{ + FAR _TCB *rtcb = (FAR _TCB*)g_readytorun.head; + + /* This equivalent to just resetting the task priority to its current value + * since this will cause the task to be rescheduled behind any other tasks + * at the same priority. + */ + + return sched_setpriority(rtcb, rtcb->sched_priority); +} |