A program which is executed in this manner must preserve the MC68000 stack frameandreturnto 1616/OS withan‘RTS’instruction. Thevaluewhichtheprogram returns in the MC68000’s d0 (data register zero) is printed out by 1616/OS when it regains control. Manually performing system calls SYSCALL callno n1 n2 n3 .... This command causes 1616/OS to perform system call number ‘callno’, with parameters n1, n2, etc. The value returned from the system call (in data register d0) is printed out upon return from the system call. If a non-numeric argument is given then the system call is passed a pointer to the non-numeric string, rather than an evaluated number, as with numeric input, so the following works:
SYSCALL .48 "%d plus %d = %d" 2 2 4 ;printf system call Refertothe 1616/OS ProgrammersReferenceManual formore (many)detailsabout system calls. Process status PS Displays a list of all current processes from the process table. Show their PID (process ID), and their parent’s ID (PPID), the amount of time theyhaveconsumed, theircurrentstatus,theirloadaddress,stackarea,theircurrent stack pointer value, the program counter value when they were last descheduled, and the handles for their standard input, output and error streams. Finally, their name is given. PID the process’s ID number, in decimal. PPID the process’s parent process PID.
HPID home PID TIME the number of 20 millsecond time slices over which the process has run, converted to minutes and seconds. Status This represents the state of five flags in the process’s process table entry. They are as follows: W Set if the process is waiting (blocked) on another. S Synchronous. A Asynchronous. E Exit pending: process about to depart. 1616/OS Commands User Tutorial Manual Page 85