nuclear@0: /*
nuclear@0: Copyright 2004 John Tsiombikas <nuclear@siggraph.org>
nuclear@0: 
nuclear@0: This file is part of libgba, a library for GameBoy Advance development.
nuclear@0: 
nuclear@0: This program is free software; you can redistribute it and/or modify
nuclear@0: it under the terms of the GNU General Public License as published by
nuclear@0: the Free Software Foundation; either version 2 of the License, or
nuclear@0: (at your option) any later version.
nuclear@0: 
nuclear@0: This program is distributed in the hope that it will be useful,
nuclear@0: but WITHOUT ANY WARRANTY; without even the implied warranty of
nuclear@0: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
nuclear@0: GNU General Public License for more details.
nuclear@0: 
nuclear@0: You should have received a copy of the GNU General Public License
nuclear@0: along with this program; if not, write to the Free Software
nuclear@0: Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
nuclear@0: */
nuclear@0: 
nuclear@0: #include <limits.h>
nuclear@0: #include "intr.h"
nuclear@0: #include "signal.h"
nuclear@0: 
nuclear@0: /* prescalar selection based on the system clock (16.78MHz) */
nuclear@0: #define TIMER_CNTL_CLK		0
nuclear@0: #define TIMER_CNTL_CLK64	1
nuclear@0: #define TIMER_CNTL_CLK256	2
nuclear@0: #define TIMER_CNTL_CLK1024	3
nuclear@0: 
nuclear@0: /* control bits */
nuclear@0: #define TIMER_CNTL_COUNTUP	4
nuclear@0: #define TIMER_CNTL_INTR		0x40
nuclear@0: #define TIMER_CNTL_ENABLE	0x80
nuclear@0: 
nuclear@0: static void timer_intr_handler(void);
nuclear@0: 
nuclear@0: volatile static unsigned short *reg_timer[] = {(void*)0x4000100, (void*)0x4000104, (void*)0x4000108, (void*)0x400010c};
nuclear@0: static unsigned short *reg_timer_cntl[] = {(void*)0x4000102, (void*)0x4000106, (void*)0x400010a, (void*)0x400010e};
nuclear@0: 
nuclear@0: static unsigned long milli_sec;
nuclear@0: static unsigned long alarm_val;
nuclear@0: 
nuclear@0: void enable_timer(int timer) {
nuclear@0: 	*reg_timer_cntl[timer] |= TIMER_CNTL_ENABLE;
nuclear@0: }
nuclear@0: 
nuclear@0: void disable_timer(int timer) {
nuclear@0: 	*reg_timer_cntl[timer] &= ~TIMER_CNTL_ENABLE;
nuclear@0: }
nuclear@0: 
nuclear@0: void reset_msec_timer(void) {
nuclear@0: 	*reg_timer_cntl[0] &= ~TIMER_CNTL_ENABLE;
nuclear@0: 	interrupt(INTR_TIMER0, timer_intr_handler);
nuclear@0: 	milli_sec = 0;
nuclear@0: 	*reg_timer[0] = USHRT_MAX - 16779;
nuclear@0: 	*reg_timer_cntl[0] = TIMER_CNTL_INTR | TIMER_CNTL_ENABLE;
nuclear@0: 	unmask(INTR_TIMER0);
nuclear@0: }
nuclear@0: 
nuclear@0: 
nuclear@0: unsigned long get_millisec(void) {
nuclear@0: 	return milli_sec;
nuclear@0: }
nuclear@0: 
nuclear@0: unsigned int alarm(unsigned int seconds) {
nuclear@0: 	unsigned int prev = alarm_val;
nuclear@0: 	alarm_val = seconds * 1000;
nuclear@0: }
nuclear@0: 
nuclear@0: static void timer_intr_handler(void) {
nuclear@0: 	milli_sec++;
nuclear@0: 
nuclear@0: 	if(alarm_val > 0) {
nuclear@0: 		if(!--alarm_val) raise(SIGALRM);
nuclear@0: 	}
nuclear@0: }