blob: 49f2acac958025265654fc0dc34fa85f07ee0570 [file] [log] [blame]
/* rtc_get_time_ms.c - get_time_ms implementation using platform RTC.
* The generic implementation of these functions can be used for architectures
* or platforms that do not have a more specialized implementation. */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2008 Free Software Foundation, Inc.
*
* GRUB is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* GRUB is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
*/
#include <grub/time.h>
#include <grub/misc.h>
#include <grub/machine/time.h>
/* Calculate the time in milliseconds since the epoch based on the RTC. */
grub_uint64_t
grub_rtc_get_time_ms (void)
{
/* By dimensional analysis:
1000 ms N rtc ticks 1 s
------- * ----------- * ----------- = 1000*N/T ms
1 s 1 T rtc ticks
*/
grub_uint64_t ticks_ms_per_sec = ((grub_uint64_t) 1000) * grub_get_rtc ();
return grub_divmod64 (ticks_ms_per_sec, GRUB_TICKS_PER_SECOND, 0);
}