Remove the idle process.

[bertos.git] / bertos / kern / coop.c

diff --git a/bertos/kern/coop.c b/bertos/kern/coop.c
index c874ca36f8bdaac539f3078c4b70efc5fe6e79c5..1b2e1bb9bc42497a193d12e736642f8155b67250 100644 (file)
--- a/bertos/kern/coop.c
+++ b/bertos/kern/coop.c
@@ -50,14 +50,6 @@
 #include <cpu/attr.h>
 #include <cpu/frame.h>
 
-/**
- * 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);
-
 /**
  * Define function prototypes exported outside.
  *
@@ -66,77 +58,11 @@ EXTERN_C void asm_switch_context(cpu_stack_t **new_sp, cpu_stack_t **save_sp);
 void coop_yield(void);
 void coop_switch(void);
 
-/**
- * System scheduler: pass CPU control to the next process in
- * the ready queue.
- */
-static void coop_schedule(void)
-{
-       cpu_flags_t flags;
-
-       ATOMIC(LIST_ASSERT_VALID(&proc_ready_list));
-       ASSERT_USER_CONTEXT();
-       IRQ_ASSERT_ENABLED();
-
-       /* Poll on the ready queue for the first ready process */
-       IRQ_SAVE_DISABLE(flags);
-       while (!(current_process = (struct Process *)list_remHead(&proc_ready_list)))
-       {
-               /*
-                * Make sure we physically reenable interrupts here, no matter what
-                * the current task status is. This is important because if we
-                * are idle-spinning, we must allow interrupts, otherwise no
-                * process will ever wake up.
-                *
-                * During idle-spinning, an interrupt can occur and it may
-                * modify \p proc_ready_list. To ensure that compiler reload this
-                * variable every while cycle we call CPU_MEMORY_BARRIER.
-                * The memory barrier ensure that all variables used in this context
-                * are reloaded.
-                * \todo If there was a way to write sig_wait() so that it does not
-                * disable interrupts while waiting, there would not be any
-                * reason to do this.
-                */
-               IRQ_ENABLE;
-               CPU_IDLE;
-               MEMORY_BARRIER;
-               IRQ_DISABLE;
-       }
-       IRQ_RESTORE(flags);
-}
-
 void coop_switch(void)
 {
-       /* Remember old process to save its context later */
-       Process * const old_process = current_process;
-
-       coop_schedule();
-
-       /*
-        * Optimization: don't switch contexts when the active
-        * process has not changed.
-        */
-       if (current_process != old_process)
-       {
-               cpu_stack_t *dummy;
-
-               #if CONFIG_KERN_MONITOR
-                       LOG_INFO("Switch from %p(%s) to %p(%s)\n",
-                               old_process,    proc_name(old_process),
-                               current_process, proc_currentName());
-               #endif
-
-               /* Save context of old process and switch to new process. 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.
-                * TODO: Instead of physically clearing the process at exit time, a zombie
-                * list should be created.
-                */
-               asm_switch_context(&current_process->stack, old_process ? &old_process->stack : &dummy);
-       }
+       IRQ_ASSERT_ENABLED();
 
-       /* This RET resumes the execution on the new process */
+       ATOMIC(proc_schedule());
 }
 
 /**
@@ -145,5 +71,5 @@ void coop_switch(void)
 void coop_yield(void)
 {
        ATOMIC(SCHED_ENQUEUE(current_process));
-       proc_switch();
+       coop_switch();
 }