+/*
+ * Check if the process context switch can be performed directly by the
+ * architecture-dependent asm_switch_context() or if it must be delayed
+ * because we're in the middle of an ISR.
+ *
+ * Return true if asm_switch_context() can be executed, false
+ * otherwise.
+ *
+ * NOTE: if an architecture does not implement IRQ_RUNNING() this function
+ * always returns true.
+ */
+#define CONTEXT_SWITCH_FROM_ISR() (!IRQ_RUNNING())
+
+#ifndef asm_switch_context
+/**
+ * CPU dependent context switching routines.
+ *
+ * Saving and restoring the context on the stack is done by a CPU-dependent
+ * support routine which usually needs to be written in assembly.
+ */
+EXTERN_C void asm_switch_context(cpu_stack_t **new_sp, cpu_stack_t **save_sp);
+#endif
+
+/*
+ * Save context of old process and switch to new process.
+ */
+INLINE void proc_switchTo(Process *next, Process *prev)
+{
+ cpu_stack_t *dummy;
+
+ if (UNLIKELY(next == prev))
+ return;
+ /*
+ * If there is no old process, we save the old stack pointer into a
+ * dummy variable that we ignore. In fact, this happens only when the
+ * old process has just exited.
+ */
+ asm_switch_context(&next->stack, prev ? &prev->stack : &dummy);
+}