target/alpha/clk_helper.c

/*
 *  QEMU Alpha clock helpers.
 *
 *  Copyright (c) 2007 Jocelyn Mayer
 *
 * SPDX-License-Identifier: LGPL-2.1-or-later
 */

#include "qemu/osdep.h"
#include "qemu/timer.h"
#include "exec/helper-proto.h"
#include "cpu.h"

uint64_t helper_load_pcc(CPUAlphaState *env)
{
#ifndef CONFIG_USER_ONLY
    /*
     * In system mode we have access to a decent high-resolution clock.
     * In order to make OS-level time accounting work with the RPCC,
     * present it with a well-timed clock fixed at 250MHz.
     */
    return (((uint64_t)env->pcc_ofs << 32)
            | (uint32_t)(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) >> 2));
#else
    /*
     * In user-mode, QEMU_CLOCK_VIRTUAL doesn't exist.  Just pass through
     * the host cpu clock ticks.  Also, don't bother taking PCC_OFS into
     * account.
     */
    return (uint32_t)cpu_get_host_ticks();
#endif
}