sysdeps/unix/sysv/aix/gettimeofday.c

   1 /* Copyright (C) 1991,92,94,95,96,97,2001,2002 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.  */
  18
  19 #include <errno.h>
  20 #include <time.h>
  21 #include <sys/time.h>
  22
  23 #ifndef HAVE_GNU_LD
  24 # define __daylight     daylight
  25 # define __timezone     timezone
  26 # define __tzname       tzname
  27 #endif
  28
  29 #undef __gettimeofday
  30
  31 extern int rtc_upper (void);
  32 extern int rtc_lower (void);
  33
  34 /* Assembler Routines to access the timer registers */
  35 asm("\n\
  36 .rtc_upper: mfspr   3,4         # copy RTCU to return register\n\
  37             blr\n\
  38 \n\
  39 .rtc_lower: mfspr   3,5         # copy RTCL to return register\n\
  40             blr\n\
  41 ");
  42
  43 /* Get the current time of day and timezone information,
  44    putting it into *TV and *TZ.  If TZ is NULL, *TZ is not filled.
  45    Returns 0 on success, -1 on errors.  */
  46 int
  47 __gettimeofday (tv, tz)
  48      struct timeval  *tv;
  49      struct timezone *tz;
  50 {
  51   int ts, tl, tu;
  52
  53   if (tv == NULL)
  54     {
  55       __set_errno (EINVAL);
  56       return -1;
  57     }
  58
  59   ts = rtc_upper ();            /* Seconds.  */
  60   tl = rtc_lower ();            /* Nanoseconds.  */
  61   tu = rtc_upper ();            /* Check for a carry from.  */
  62   if (ts != tu)                 /* The lower reg to the upper.  */
  63       tl  = rtc_lower ();       /* Recover from the race condition.  */
  64
  65   tv->tv_sec  = (long int) (tu + (double) tl / 1000000000);
  66   tv->tv_usec = (long int) ((double) tl / 1000);
  67
  68   if (tz != NULL)
  69     {
  70       const  time_t timer = tv->tv_sec;
  71       struct tm tm;
  72       const  struct tm *tmp;
  73
  74       const long int save_timezone = __timezone;
  75       const long int save_daylight = __daylight;
  76       char *save_tzname[2];
  77       save_tzname[0] = __tzname[0];
  78       save_tzname[1] = __tzname[1];
  79
  80       tmp = localtime_r (&timer, &tm);
  81
  82       tz->tz_minuteswest = __timezone / 60;
  83       tz->tz_dsttime     = __daylight;
  84
  85       __timezone  = save_timezone;
  86       __daylight  = save_daylight;
  87       __tzname[0] = save_tzname[0];
  88       __tzname[1] = save_tzname[1];
  89
  90       if (tmp == NULL)
  91         return -1;
  92     }
  93
  94   return 0;
  95 }
  96
  97 INTDEF(__gettimeofday)
  98 weak_alias (__gettimeofday, gettimeofday)