// nos-z  nut operating system in Rz
//  model after nos2 in ecse\src    22 Aug 2011
//  run two process (showTwoCount)  23 Aug 2011
//  new Rz syntax and add monitor   28 Aug 2011

syscall(a)   // anchor for compiler
  a = 0

new(n)      // alloc n
  syscall(14,n)
ei()
  syscall(20)
di()
  syscall(21)
getevent()
  return syscall(22)
blockp()
  syscall(23)
bootnos()
  syscall(24)

// global

activep      // current active process
psw          // switchp
sseg         // stack segment
pid          // unique process id

// event
TIMEOUT, STOP, BLOCK

// process descriptor

// 0 next, 1 prev
// 2 id,   3 value
// 4 fp,   5 sp,  6 pc, 7 -
// 8 inbox, 9 awaitbox, 10 msg


// process state
READY, RUNNING, WAIT, DEAD, SEND, RECEIVE

init()
  TIMEOUT = 10
  STOP = 13
  BLOCK = 11
  READY = 1
  RUNNING = 2
  WAIT = 3
  DEAD = 4
  SEND = 5
  RECEIVE = 6
  pid = 1
  sseg = 1000
  activep = 0


//  process descriptor access function

getNext(a)
  return a[0]
getPrev(a)
  return a[1]
setNext(a,v)
  a[0] = v
setPrev(a,v)
  a[1] = v

getId(p)
  return p[2]
getValue(p)
  return p[3]
setId(p,id)
  p[2] = id
setValue(p, v)
  p[3] = v

// ---- process list functions --------

// append a2 to the end of a1
appendDL(a1,a2)
  if(a1 == 0)
    setNext(a2,a2)  // only one item
    setPrev(a2,a2)
    return a2
  else
    b = getPrev(a1)
    setNext(a2,a1)
    setPrev(a1,a2)
    setNext(b,a2)
    setPrev(a2,b)
    return a1

deleteDL(b)
  if(getNext(b) == 0)
    return 0         // delete singleton
  else
    a = getPrev(b)
    c = getNext(b)
    setNext(a,c)
    setPrev(c,a)
    setNext(b,0)    // make b singleton
    return c

showp(a)            // show pid,sseg,ip
  p = a
  while(p != 0)
    print(p[2]," ",p[4]," ",p[6],"\n")
    p = getNext(p)
    if(p == a) p = 0
  print("\n")

newp()              // new process
  p = new(11)       // new pdes
  setNext(p,0)
  setPrev(p,0)
  setValue(p,READY)
  p[4] = sseg
  p[5] = sseg + 1
  p[6] = 0
  sseg = sseg + 1000
  p[7] = 0
  p[8] = 0
  return p

// -------nos functions --------

run(ads)   // return p
  p = newp()
  setId(p,pid)
  pid = pid + 1
  p[6] = ads
  activep = appendDL(activep, p)
  return p

switchp()   // previlege process
  di()
  event = getevent()
  if(event == STOP)
    setValue(activep,DEAD)
    activep = deleteDL(activep)
  else		// TIMEOUT, BLOCK
    setValue(activep,READY)
    activep = getNext(activep) // switch next
  ei()

// -------- user program ------

count1()
  i = 10
  while(i < 100)
    print(i," ")
    i = i + 2

count2()
  i = 3
  while(i < 100)
    print(i," ")
    i = i + 2

// --- applications ----------

p1, p2			// user process

main()
  init()
  psw = run(switchp())
  activep = 0
  // start user process
  p1 = run(count1())
  p2 = run(count2())
  bootnos()

// end