xref: /barrelfish-master/lib/posixcompat/time.c

/*
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/*
 * Copyright (c) 2011, ETH Zurich.
 * All rights reserved.
 *
 * This file is distributed under the terms in the attached LICENSE file.
 * If you do not find this file, copies can be found by writing to:
 * ETH Zurich D-INFK, Universitaetstrasse 6, CH-8092 Zurich. Attn: Systems Group.
 */

#define _USE_XOPEN
#include <time.h>
#include <assert.h>
#include <barrelfish/barrelfish.h>
#include <barrelfish/sys_debug.h>

// XXX: Fake Epoch offset, until we have an RTC driver
// This is roughly Mon Apr 25 13:50 CEST 2011
#define TOD_OFFSET      1303732456ULL

time_t
time(time_t *timer)
{
    // XXX: What about TSC overflow?
    uint64_t now = rdtsc();

#if defined(__arm__)
    uint32_t tscrate;
    errval_t err = sys_debug_hardware_timer_hertz_read(&tscrate);
    assert(err_is_ok(err));

    assert(tscrate > 0);
    uint64_t tod = TOD_OFFSET + (now / tscrate);
#else
    uint64_t tscperms;
    errval_t err = sys_debug_get_tsc_per_ms(&tscperms);
    assert(err_is_ok(err));

    assert(tscperms > 0);
    uint64_t tod = TOD_OFFSET + (now / (tscperms * 1000));
#endif

    time_t val = tod;
    if (timer)
        *timer = val;
    return val;
}