emulate.cxx

eCos操作系统源码

//==========================================================================
//
//      io/wallclock/emulate.cxx
//
//      Wallclock emulation implementation
//
//==========================================================================
//####ECOSGPLCOPYRIGHTBEGIN####
// -------------------------------------------
// This file is part of eCos, the Embedded Configurable Operating System.
// Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.
//
// eCos 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 2 or (at your option) any later version.
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// 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 eCos; if not, write to the Free Software Foundation, Inc.,
// 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
//
// As a special exception, if other files instantiate templates or use macros
// or inline functions from this file, or you compile this file and link it
// with other works to produce a work based on this file, this file does not
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// in accordance with section (3) of the GNU General Public License.
//
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// this file might be covered by the GNU General Public License.
//
// Alternative licenses for eCos may be arranged by contacting Red Hat, Inc.
// at http://sources.redhat.com/ecos/ecos-license/
// -------------------------------------------
//####ECOSGPLCOPYRIGHTEND####
//==========================================================================
//#####DESCRIPTIONBEGIN####
//
// Author(s):     nickg
// Contributors:  nickg
// Date:          1999-03-05
// Purpose:       Wallclock emulation
//
//####DESCRIPTIONEND####
//
//==========================================================================

#include <pkgconf/wallclock.h>          // Wallclock device config
#include <pkgconf/kernel.h>             // Kernel config

#include <cyg/infra/cyg_type.h>         // Common type definitions and support
#include <cyg/kernel/ktypes.h>

#include <cyg/io/wallclock.hxx>         // The WallClock API

#include <cyg/kernel/clock.hxx>         // Access to kernel clock
#include <cyg/kernel/clock.inl>


// Remember the tick count at the time of initialization.
static cyg_tick_count epoch_ticks;

//-----------------------------------------------------------------------------
// Called to initialize the hardware clock with a known valid
// time. Which of course isn't required when doing emulation using the
// kernel clock. But we set the private epoch base to "now".
void
Cyg_WallClock::init_hw_seconds( void )
{
    // Remember the current clock tick count.
    epoch_ticks = Cyg_Clock::real_time_clock->current_value();
}

//-----------------------------------------------------------------------------
// Returns the number of seconds elapsed since the init call.
cyg_uint32 
Cyg_WallClock::get_hw_seconds( void )
{
    Cyg_Clock::cyg_resolution res = 
        Cyg_Clock::real_time_clock->get_resolution();
    cyg_tick_count secs = Cyg_Clock::real_time_clock->current_value()
        - epoch_ticks;

    secs = secs / ( ( res.divisor * 1000000000LL ) / res.dividend );

    return secs;
}

//-----------------------------------------------------------------------------
// End of devs/wallclock/emulate.cxx