rom/kernel/kernel_intr.c

   1 /*
   2     Copyright © 2011-2015, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: High-level scheduler calling code
   6     Lang: English
   7 */
   8
   9 #include <exec/execbase.h>
  10 #include <hardware/intbits.h>
  11 #include <proto/exec.h>
  12
  13 #include <kernel_base.h>
  14 #include <kernel_intr.h>
  15 #include <kernel_scheduler.h>
  16 #include <kernel_syscall.h>
  17
  18 #include "exec_platform.h"
  19
  20 /*
  21  * Leave the interrupt. This function receives the interrupt register frame
  22  * and runs task scheduler if needed.
  23  *
  24  * You should call it only if you're returning to user mode (i.e. not from
  25  * within nested interrupt).
  26  *
  27  * It relies on CPU-specific cpu_Switch() and cpu_Dispatch() implementations
  28  * which save and restore CPU context. cpu_Dispatch() is allowed just to
  29  * jump to the saved context and not return here.
  30  */
  31 void core_ExitInterrupt(regs_t *regs)
  32 {
  33     /* Soft interrupt requested? It's high time to do it */
  34     if (SysBase->SysFlags & SFF_SoftInt)
  35         core_Cause(INTB_SOFTINT, 1L << INTB_SOFTINT);
  36
  37     /* If task switching is disabled, do nothing */
  38     if (TDNESTCOUNT_GET < 0)
  39     {
  40         /*
  41          * Do not disturb task if it's not necessary.
  42          * Reschedule only if switch pending flag is set. Exit otherwise.
  43          */
  44         if (FLAG_SCHEDSWITCH_ISSET)
  45         {
  46             /* Run task scheduling sequence */
  47             if (core_Schedule())
  48             {
  49                 cpu_Switch(regs);
  50                 cpu_Dispatch(regs);
  51             }
  52         }
  53     }
  54 }
  55
  56 /*
  57  * This routine dispatches scheduler's SysCall, when some task wants to give up
  58  * the CPU time explicitly.
  59  * Similar to above, it should be called only when you're returning to user mode.
  60  */
  61 void core_SysCall(int sc, regs_t *regs)
  62 {
  63     switch (sc)
  64     {
  65     case SC_CAUSE:
  66         core_ExitInterrupt(regs);
  67         break;
  68
  69     case SC_SCHEDULE:
  70         if (!core_Schedule())
  71             break;
  72         /* Fallthrough */
  73
  74     case SC_SWITCH:
  75         cpu_Switch(regs);
  76         /* Fallthrough */
  77
  78     case SC_DISPATCH:
  79         cpu_Dispatch(regs);
  80         break;
  81     }
  82 }