From 8a365179eafdf3aea98e60ab9f5882b200d4c759 Mon Sep 17 00:00:00 2001
From: px4dev <px4@purgatory.org>
Date: Sat, 4 Aug 2012 15:12:36 -0700
Subject: Fresh import of the PX4 firmware sources.

---
 nuttx/arch/arm/src/armv7-m/up_releasepending.c | 129 +++++++++++++++++++++++++
 1 file changed, 129 insertions(+)
 create mode 100755 nuttx/arch/arm/src/armv7-m/up_releasepending.c

(limited to 'nuttx/arch/arm/src/armv7-m/up_releasepending.c')

diff --git a/nuttx/arch/arm/src/armv7-m/up_releasepending.c b/nuttx/arch/arm/src/armv7-m/up_releasepending.c
new file mode 100755
index 000000000..2f0d4dc39
--- /dev/null
+++ b/nuttx/arch/arm/src/armv7-m/up_releasepending.c
@@ -0,0 +1,129 @@
+/****************************************************************************
+ *  arch/arm/src/armv7-m/up_releasepending.c
+ *
+ *   Copyright (C) 2007-2009, 2012 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 <sched.h>
+#include <debug.h>
+#include <nuttx/arch.h>
+
+#include "os_internal.h"
+#include "up_internal.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: up_release_pending
+ *
+ * Description:
+ *   Release and ready-to-run tasks that have
+ *   collected in the pending task list.  This can call a
+ *   context switch if a new task is placed at the head of
+ *   the ready to run list.
+ *
+ ****************************************************************************/
+
+void up_release_pending(void)
+{
+  _TCB *rtcb = (_TCB*)g_readytorun.head;
+
+  slldbg("From TCB=%p\n", rtcb);
+
+  /* Merge the g_pendingtasks list into the g_readytorun task list */
+
+  /* sched_lock(); */
+  if (sched_mergepending())
+    {
+      /* The currently active task has changed!  We will need to switch
+       * contexts.  First check if we are operating in interrupt context.
+       */
+
+      if (current_regs)
+        {
+          /* Yes, then we have to do things differently. Just copy the
+           * current_regs into the OLD rtcb.
+           */
+
+           up_savestate(rtcb->xcp.regs);
+
+          /* Restore the exception context of the rtcb at the (new) head 
+           * of the g_readytorun task list.
+           */
+
+          rtcb = (_TCB*)g_readytorun.head;
+          slldbg("New Active Task TCB=%p\n", rtcb);
+
+          /* Then switch contexts */
+
+          up_restorestate(rtcb->xcp.regs);
+        }
+
+      /* No, then we will need to perform the user context switch */
+
+      else
+        {
+          /* Switch context to the context of the task at the head of the
+           * ready to run list.
+           */
+
+          _TCB *nexttcb = (_TCB*)g_readytorun.head;
+          up_switchcontext(rtcb->xcp.regs, nexttcb->xcp.regs);
+
+          /* up_switchcontext forces a context switch to the task at the
+           * head of the ready-to-run list.  It does not 'return' in the
+           * normal sense.  When it does return, it is because the blocked
+           * task is again ready to run and has execution priority.
+           */
+        }
+    }
+}
-- 
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