FreeBSD/Linux Kernel Cross Reference
sys/i386/hardclock.c

     /* 
      * Mach Operating System
      * Copyright (c) 1991,1990 Carnegie Mellon University
      * Copyright (c) 1991 IBM Corporation 
      * All Rights Reserved.
      * 
      * Permission to use, copy, modify and distribute this software and its
      * documentation is hereby granted, provided that both the copyright
      * notice and this permission notice appear in all copies of the
     * software, derivative works or modified versions, and any portions
     * thereof, and that both notices appear in supporting documentation,
     * and that the name IBM not be used in advertising or publicity 
     * pertaining to distribution of the software without specific, written
     * prior permission.
     * 
     * CARNEGIE MELLON AND IBM ALLOW FREE USE OF THIS SOFTWARE IN ITS "AS IS"
     * CONDITION.  CARNEGIE MELLON AND IBM DISCLAIM ANY LIABILITY OF ANY KIND FOR
     * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
     * 
     * Carnegie Mellon requests users of this software to return to
     * 
     *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
     *  School of Computer Science
     *  Carnegie Mellon University
     *  Pittsburgh PA 15213-3890
     * 
     * any improvements or extensions that they make and grant Carnegie Mellon
     * the rights to redistribute these changes.
     */
    
    
    /*
     * HISTORY
     * $Log:        hardclock.c,v $
     * Revision 2.9  93/02/04  07:56:18  danner
     *      Integrate PS2 and non PS2 cases into one routine.
     *      [93/01/25            rvb]
     * 
     *      Don't check for SPL 0 here.  Interrupt return code checks
     *      for pending softclock interrupt.
     *      [92/04/19            dbg@ibm]
     * 
     *      PS2-only version.  Different interrupt stack format,
     *      clock interrupt reset code.  Does NOT use ABIOS.
     *      [92/03/30            dbg@ibm]
     * 
     * Revision 2.8  91/07/31  17:36:33  dbg
     *      New interrupt save area.
     *      [91/07/30  16:50:59  dbg]
     * 
     * Revision 2.7  91/06/19  11:55:09  rvb
     *      cputypes.h->platforms.h
     *      [91/06/12  13:44:49  rvb]
     * 
     * Revision 2.6  91/05/14  16:08:38  mrt
     *      Correcting copyright
     * 
     * Revision 2.5  91/05/08  12:37:56  dbg
     *      Include sqt/intctl.h if building for Sequent.
     *      [91/03/21            dbg]
     * 
     * Revision 2.4  91/02/05  17:12:01  mrt
     *      Changed to new Mach copyright
     *      [91/02/01  17:34:29  mrt]
     * 
     * Revision 2.3  91/01/08  17:32:02  rpd
     *      EFL_VM => user_mode
     *      [90/12/21  10:50:54  rvb]
     * 
     * Revision 2.2  90/05/03  15:27:35  dbg
     *      Created.
     *      [90/03/06            dbg]
     * 
     */
    
    /*
     * Clock interrupt.
     */
    #include <platforms.h>
    
    #include <kern/time_out.h>
    #include <i386/thread.h>
    #include <i386/eflags.h>
    
    #ifdef  SYMMETRY
    #include <sqt/intctl.h>
    #endif
    #if     defined(AT386) || defined(iPSC386)
    #include <i386/ipl.h>
    #endif
    #ifdef  PS2
    #include <i386/pic.h>
    #include <i386/pio.h>
    #endif  PS2
    
    extern void     clock_interrupt();
    extern char     return_to_iret[];
    
    void
   #ifdef  PS2
   hardclock(iunit, ivect, old_ipl, ret_addr, regs)
           int     iunit;          /* 'unit' number */
           int     ivect;          /* interrupt number */
   #else   /* PS2 */
   hardclock(iunit,        old_ipl, ret_addr, regs)
           int     iunit;          /* 'unit' number */
           int     old_ipl;        /* old interrupt level */
   #endif  /* PS2 */
           char *  ret_addr;       /* return address in interrupt handler */
           struct i386_interrupt_state *regs;
                                   /* saved registers */
   {
           if (ret_addr == return_to_iret)
               /*
                * Interrupt from user mode or from thread stack.
                */
               clock_interrupt(tick,                       /* usec per tick */
                               (regs->efl & EFL_VM) ||     /* user mode */
                               ((regs->cs & 0x03) != 0),   /* user mode */
   #ifdef  PS2
                               FALSE                       /* ignore SPL0 */
   #else   /* PS2 */
                               old_ipl == SPL0             /* base priority */
   #endif  /* PS2 */
                               );
           else
               /*
                * Interrupt from interrupt stack.
                */
               clock_interrupt(tick,                       /* usec per tick */
                               FALSE,                      /* kernel mode */
                               FALSE);                     /* not SPL0 */
   
   #ifdef  PS2
           /*
            * Reset the clock interrupt line.
            */
           outb(0x61, inb(0x61) | 0x80);
   #endif  /* PS2 */
   }                               

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