/* Soil Sensor Firmware
 * Timekeeping
 * Sensiplicity Systems
 * 
 *  Copyright 2015
 * 
 *  Department of Botany and Plant Pathology
 *  Center for Genome Research and Biocomputing
 *  Oregon State University
 *  Corvallis, OR 97331
 * 
 * This program is not free software; you can not redistribute it and/or
 * modify it at all.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. */
#include <avr/interrupt.h>
#include <util/atomic.h>

#include "time.h"


/* Get the number of seconds since the system was powered on. */
uint32_t get_uptime(void){
	return 0;
}

/* Wait for a condition to become true, timing out after a given
 * time. The condition is defined by a value, mask, and polarity.
 * The mask is a bitmask that selects bit(s) in a value. If polarity
 * is not 0, the condition is true when any of the bits are 1. If
 * polarity is 0, the condition is true when all are 0.
 * 
 * The timeout value is in milliseconds. The maximum timeout is 127 milliseconds.
 * 
 * Returns 0 if the condition became true, -1 if a timeout occurred. */
int8_t wait_condition(volatile uint8_t *value, uint8_t mask, uint8_t polarity, uint8_t timeout_ms){
	uint32_t count = 0;
	uint32_t limit = timeout_ms * 200;/* Assuming 10 clock cycles per loop iteration. */
	
	while(1){
		if(polarity){
			if(*value & mask){
				return 0;
			}
		} else {
			if(!(*value & mask)){
				return 0;
			}
		}
		count++;
		if(count > limit)return -1;
	}
}