#include <stdio.h>
#include "enet_cs.h"
long critical_status=NORMAL;
int i, j, node, turn_num, flag_num;
/* Program by Matt Weisfeld */
main(argc,argv)
int argc;
char **argv;
{
fprintf (stderr,"%sENET_CS%s(1.0)\n", bold,norm);
if (argc != 2) {
printf ("Error: bad number of args.\n");
exit(0);
}
node = atoi(argv[1]);
intro(); /* print out informational messages */
i = node;
/* perform critical function until exit condition exists */
while (critical_status == NORMAL) {
perform();
}
return;
}
perform()
{
/*
A do-while (!expression) is the same as
do-until (expression)
*/
do {
cs_write ( i, WANT_IN);
turn_num = cs_read ( TURN_LOC);
j = turn_num;
while (j != i) {
flag_num = cs_read ( j);
if (flag_num != IDLE) {
turn_num = cs_read ( TURN_LOC);
j = turn_num;
} else {
j = (j+1) % PROCESSES;
}
}
cs_write ( i, IN_CS);
j = 0;
flag_num = cs_read ( j);
while ((j<PROCESSES-1) &&
(j==i || flag_num!=IN_CS) ) {
j++;
flag_num = cs_read ( j);
}
turn_num = cs_read ( TURN_LOC);
flag_num = cs_read ( turn_num);
}while (!((j>=PROCESSES-1) &&
((turn_num == i) || flag_num == IDLE)));
turn_num = i;
cs_write ( TURN_LOC, turn_num);
/* enter critical section */
critical_status = critical_section();
/* leave critical section */
turn_num = cs_read ( TURN_LOC);
j = (turn_num+1) % PROCESSES;
flag_num = cs_read ( j);
while (flag_num == IDLE) {
j = (j+1) % PROCESSES;
flag_num = cs_read ( j);
}
turn_num = j;
cs_write ( TURN_LOC, turn_num);
flag_num = IDLE;
cs_write ( i, flag_num);
}
intro()
{
switch (node) {
case NODE0:
printf ("PROCESSOR NODE0\n");
break;
case NODE1:
printf ("PROCESSOR NODE1\n");
break;
case NODE2:
printf ("PROCESSOR NODE2\n");
break;
default:
printf ("Error: invalid processor\n");
exit(0);
break;
}
}
/* End of File */