50 lines
1.7 KiB
C
50 lines
1.7 KiB
C
|
/* -*- Mode: C; c-basic-offset: 3 -*-
|
||
|
|
*
|
||
|
|
* timer.c - Interfaces for the various timers available on PC hardware.
|
||
|
|
*
|
||
|
|
* This file is part of Metalkit, a simple collection of modules for
|
||
|
|
* writing software that runs on the bare metal. Get the latest code
|
||
|
|
* at http://svn.navi.cx/misc/trunk/metalkit/
|
||
|
|
*
|
||
|
|
* Copyright (c) 2008-2009 Micah Dowty
|
||
|
|
*
|
||
|
|
* Permission is hereby granted, free of charge, to any person
|
||
|
|
* obtaining a copy of this software and associated documentation
|
||
|
|
* files (the "Software"), to deal in the Software without
|
||
|
|
* restriction, including without limitation the rights to use,
|
||
|
|
* copy, modify, merge, publish, distribute, sublicense, and/or sell
|
||
|
|
* copies of the Software, and to permit persons to whom the
|
||
|
|
* Software is furnished to do so, subject to the following
|
||
|
|
* conditions:
|
||
|
|
*
|
||
|
|
* The above copyright notice and this permission notice shall be
|
||
|
|
* included in all copies or substantial portions of the Software.
|
||
|
|
*
|
||
|
|
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
|
||
|
|
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
|
||
|
|
* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
|
||
|
|
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
|
||
|
|
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
|
||
|
|
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
|
||
|
|
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
|
||
|
|
* OTHER DEALINGS IN THE SOFTWARE.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include "timer.h"
|
||
|
|
#include "io.h"
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Timer_InitPIT --
|
||
|
|
*
|
||
|
|
* Set up PIT channel 0 in rate timer mode, with the provided
|
||
|
|
* divisor. It will trigger IRQ 0 at (PIT_HZ / divisor) Hz.
|
||
|
|
*/
|
||
|
|
|
||
|
|
fastcall void
|
||
|
|
Timer_InitPIT(uint16 divisor)
|
||
|
|
{
|
||
|
|
IO_Out8(0x43, 0x34);
|
||
|
|
IO_Out8(0x40, divisor & 0xFF);
|
||
|
|
IO_Out8(0x40, divisor >> 8);
|
||
|
|
}
|