66 lines
1.2 KiB
C
66 lines
1.2 KiB
C
|
/*
|
||
|
|
* Raspberry Pi support library for the ACK
|
||
|
|
* © 2013 David Given
|
||
|
|
* This file is redistributable under the terms of the 3-clause BSD license.
|
||
|
|
* See the file 'Copying' in the root of the distribution for the full text.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include <stdlib.h>
|
||
|
|
#include <errno.h>
|
||
|
|
#include <unistd.h>
|
||
|
|
#include <time.h>
|
||
|
|
#include <pi.h>
|
||
|
|
#include "libsys.h"
|
||
|
|
|
||
|
|
#define TICKS_PER_SEC 1000000
|
||
|
|
|
||
|
|
typedef int condition_t(void);
|
||
|
|
|
||
|
|
static int nop_condition(void)
|
||
|
|
{
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
int select(int nfds, fd_set *readfds, fd_set *writefds,
|
||
|
|
fd_set *exceptfds, struct timeval *timeout)
|
||
|
|
{
|
||
|
|
int result = 0;
|
||
|
|
condition_t* condition = nop_condition;
|
||
|
|
|
||
|
|
if (FD_ISSET(0, readfds))
|
||
|
|
condition = _sys_rawpoll;
|
||
|
|
|
||
|
|
FD_ZERO(readfds);
|
||
|
|
FD_ZERO(writefds);
|
||
|
|
FD_ZERO(exceptfds);
|
||
|
|
|
||
|
|
if (timeout)
|
||
|
|
{
|
||
|
|
/* Wait for a specified amount of time. */
|
||
|
|
|
||
|
|
uint32_t ticks = (timeout->tv_sec * TICKS_PER_SEC) +
|
||
|
|
(timeout->tv_usec * (TICKS_PER_SEC/1000000));
|
||
|
|
uint32_t* timer_clo = pi_phys_to_user((void*) 0x7e003004);
|
||
|
|
uint32_t ra = *timer_clo;
|
||
|
|
|
||
|
|
while (!condition() && ((*timer_clo - ra) < ticks))
|
||
|
|
;
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
/* Wait forever. */
|
||
|
|
|
||
|
|
while (!condition())
|
||
|
|
;
|
||
|
|
|
||
|
|
}
|
||
|
|
|
||
|
|
if ((condition == _sys_rawpoll) && condition())
|
||
|
|
{
|
||
|
|
FD_SET(0, readfds);
|
||
|
|
result = 1;
|
||
|
|
}
|
||
|
|
|
||
|
|
return result;
|
||
|
|
}
|