rom/kernel/kernel_intr.c

   1 /*
   2     Copyright © 2011, 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 /*
  19  * Leave the interrupt. This function receives the interrupt register frame
  20  * and runs task scheduler if needed.
  21  *
  22  * You should call it only if you're returning to user mode (i.e. not from
  23  * within nested interrupt).
  24  *
  25  * It relies on CPU-specific cpu_Switch() and cpu_Dispatch() implementations
  26  * which save and restore CPU context. cpu_Dispatch() is allowed just to
  27  * jump to the saved context and not return here.
  28  */
  29 void core_ExitInterrupt(regs_t *regs)
  30 {
  31     /* Soft interrupt requested? It's high time to do it */
  32     if (SysBase->SysFlags & SFF_SoftInt)
  33         core_Cause(INTB_SOFTINT, 1L << INTB_SOFTINT);
  34
  35     /* If task switching is disabled, do nothing */
  36     if (SysBase->TDNestCnt < 0)
  37     {
  38         /*
  39          * Do not disturb task if it's not necessary.
  40          * Reschedule only if switch pending flag is set. Exit otherwise.
  41          */
  42         if (SysBase->AttnResched & ARF_AttnSwitch)
  43         {
  44             /* Run task scheduling sequence */
  45             if (core_Schedule())
  46             {
  47                 cpu_Switch(regs);
  48                 cpu_Dispatch(regs);
  49             }
  50         }
  51     }
  52 }
  53
  54 /*
  55  * This routine dispatches scheduler's SysCall, when some task wants to give up
  56  * the CPU time explicitly.
  57  * Similar to above, it should be called only when you're returning to user mode.
  58  */
  59 void core_SysCall(int sc, regs_t *regs)
  60 {
  61     switch (sc)
  62     {
  63     case SC_CAUSE:
  64         core_ExitInterrupt(regs);
  65         break;
  66
  67     case SC_SCHEDULE:
  68         if (!core_Schedule())
  69             break;
  70         /* Fallthrough */
  71
  72     case SC_SWITCH:
  73         cpu_Switch(regs);
  74         /* Fallthrough */
  75
  76     case SC_DISPATCH:
  77         cpu_Dispatch(regs);
  78         break;
  79     }
  80 }