diff options
Diffstat (limited to 'grub-core/kern/generic/rtc_get_time_ms.c')
-rw-r--r-- | grub-core/kern/generic/rtc_get_time_ms.c | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/grub-core/kern/generic/rtc_get_time_ms.c b/grub-core/kern/generic/rtc_get_time_ms.c new file mode 100644 index 0000000..3e39c8f --- /dev/null +++ b/grub-core/kern/generic/rtc_get_time_ms.c @@ -0,0 +1,38 @@ +/* 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 ? : 1000, 0); +} |