void scheduler() {
// Init no longer has children. Needs to close.
if (jrb_empty(init->children)) {
SYSHalt();
}
if(dll_empty(readyQ)) {
noop_flag = 1;
noop();
} else {
PCB *process;
Dllist node;
Jval registers;
noop_flag = 0;
process = (PCB *) malloc(sizeof(PCB));
node = dll_first(readyQ); // Get next node in queue
dll_delete_node(node); // Node in memory. Delete off readyQ
// Get registers from node
registers = dll_val(node);
process = (PCB *)jval_v(registers);
// Update current process
currentProcess = process;
User_Base = process->base;
User_Limit = process->limit;
run_user_code(process->registers);
}
}
void
exceptionHandler(ExceptionType which)
{
int type, r5, r6, r7, newPC;
int buf[NumTotalRegs];
examine_registers(buf);
type = buf[4];
r5 = buf[5];
r6 = buf[6];
r7 = buf[7];
newPC = buf[NextPCReg];
/*
* for system calls type is in r4, arg1 is in r5, arg2 is in r6, and
* arg3 is in r7 put result in r2 and don't forget to increment the
* pc before returning!
*/
//set current register to buf.
setReg(current, buf);
switch (which) {
case SyscallException:
/* the numbers for system calls is in <sys/syscall.h> */
switch (type) {
case 0:
/* 0 is our halt system call number */
DEBUG('e', "Halt initiated by user program\n");
SYSHalt();
case SYS_exit:
/* this is the _exit() system call */
DEBUG('e', "SYS Exit\n");
kt_fork(do_exit,current);
break;
case SYS_read:
DEBUG('e', "SYS Read\n");
kt_fork(do_read,current);
break;
case SYS_write:
DEBUG('e', "SYS Write\n");
kt_fork(do_write,current);
break;
case SYS_ioctl:
DEBUG('e',"Sys ioctl\n");
kt_fork(do_ioctl,current);
break;
case SYS_fstat:
DEBUG('e',"Sys fstat\n");
kt_fork(do_fstat,current);
break;
case SYS_getpagesize:
DEBUG('e', "Sys getpagesize\n");
kt_fork(do_getpagesize,current);
break;
case SYS_sbrk:
DEBUG('e',"Sys_sbrk\n");
kt_fork(do_sbrk,current);
break;
case SYS_execve:
DEBUG('e',"Sys execve\n");
kt_fork(do_execve,current);
break;
case SYS_getpid:
DEBUG('e',"SYS_getpid\n");
kt_fork(do_getpid,current);
break;
case SYS_fork:
DEBUG('e', "SYS_fork\n");
kt_fork(do_fork,current);
break;
case SYS_getppid:
DEBUG('e', "SYS_getppid\n");
kt_fork(do_getppid,current);
//SYSHalt();//STUB
break;
case SYS_wait:
DEBUG('e', "SYS_wait\n");
//SYSHalt();//STUB
kt_fork(do_wait,current);
break;
case SYS_getdtablesize:
DEBUG('e', "SYS_getdtablesize\n");
kt_fork(do_getdtablesize,current);
break;
case SYS_close:
DEBUG('e', "SYS_close\n");
kt_fork(do_close,current);
break;
case SYS_pipe:
DEBUG('e', "SYS_pipe\n");
kt_fork(do_pipe,current);
break;
case SYS_dup:
DEBUG('e', "SYS_dup\n");
kt_fork(do_dup,current);
break;
case SYS_dup2:
DEBUG('e', "SYS_dup2\n");
kt_fork(do_dup2,current);
break;
default:
DEBUG('e', "Unknown system call\n");
SYSHalt();
break;
}
break;
case PageFaultException:
DEBUG('e', "Exception PageFaultException\n");
break;
case BusErrorException:
DEBUG('e', "Exception BusErrorException\n");
break;
case AddressErrorException:
DEBUG('e', "Exception AddressErrorException\n");
break;
case OverflowException:
DEBUG('e', "Exception OverflowException\n");
break;
case IllegalInstrException:
DEBUG('e', "Exception IllegalInstrException\n");
break;
default:
printf("Unexpected user mode exception %d %d\n", which, type);
exit(1);
}
scheduler();
}