1. Computer Architecture and Assembly Language
Practical Session 8

2. Game of life Simulates Evolution of two-dimensional matrix’s cells.
Each cell can be alive or dead.
A cell’s state in each iteration (generation) is set with accordance to its state and its neighbors’ states.

3. Cell neighbors Every cell has 8 neighbors Even at the board edges me
cells of the first row are neighbors of the cells in the last row
cells of the first column are neighbors of the cells in the last column

4. Game rules
If the cell is currently alive, then it will remain alive in the next generation if and only if exactly 2 or 3 of its neighbors are currently alive. Otherwise it dies.
Examples: N3 N2 N1 N5 me N4 N8 N7 N6 N3 N2 N1 N5 me N4 N8 N7 N6
me dies
me stays alive N3 N2 N1 N5 me N4 N8 N7 N6
A dead cell remains dead in the next generation, unless it has exactly 3 living neighbors.
Examples: N3 N2 N1 N5 me N4 N8 N7 N6 N3 N2 N1 N5 me N4 N8 N7 N6
me comes alive
me stays dead
Organism age is the number of generation it was alive in a row. Maximum age is 9*. *A cell does not die after age 9, it continues its life according to the game rules, but its age stays unchanged.

5. Input file Each cell is given an initial state from input file.1
alive cells are denoted by ‘1’ in input file
empty (dead) cells are denoted by space in input file
At each generation, a cell will determine its next state according to its former state and its neighbors’ former states, using the game rules. After calculation of the next state, each cell updates its state. 1 1 2 1
calculate next state
update next state

6. n cell instances (2-dimensional matrix) printer scheduler
Implementation
Using the co-routine mechanism, with the following co-routines:
n cell instances (2-dimensional matrix)
printer
scheduler

7. (stage 1) resume  (stage 2) resume
Cell
Cell can be alive(‘1’-’9’) or dead(‘ ‘)
Cell executes a simple infinite loop:
Calculate next state using current state (of a cell and its neighbors)
Update current state of to a new state
After each of these two stages, the cell co-routine must resume the scheduler.
In other words, it loops (forever) over:
(stage 1) resume  (stage 2) resume

8. Scheduler Printer implements simple round-robin algorithm
void scheduler (int cycles)
iterate cycles times over all cells
after each K resumes of cell co-routines, resume the printer (1) resume  (2) resume …
right before exit the program, resume the printer once more, and then terminate the process
What is the definition of K??
Printer
prints the entire “world” (the global array), whenever it gets “time”

9. Program’s flow row=0, column=0
while (numberOfGenerations < maximalNumberOfGenerations)
resume(cell (row, column))
if (time to resume printer)
resume (printer)
column=(column+1)%maximalNumberOfColumns
if(column ==0)
row=(row+1)%maximalNumberOfRows
if (row==0 && column==0)
numberOfGenerations+=0.5
Printer
Scheduler
Cell (0,0)
Cell (0,1) …
Cell (n-1, n-1)
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix … … …

10. Program’s flow row=0, column=0
while (numberOfGenerations < maximalNumberOfGenerations)
resume(cell (row, column))
if (time to resume printer)
resume (printer)
column=(column+1)%maximalNumberOfColumns
if(column ==0)
row=(row+1)%maximalNumberOfRows
if (row==0 && column==0)
numberOfGenerations+=0.5
Printer
Scheduler
Cell (0,0)
Cell (0,1) …
Cell (n-1, n-1)
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix … … …

11. Program’s flow row=0, column=0
while (numberOfGenerations < maximalNumberOfGenerations)
resume(cell (row, column))
if (time to resume printer)
resume (printer)
column=(column+1)%maximalNumberOfColumns
if(column ==0)
row=(row+1)%maximalNumberOfRows
if (row==0 && column==0)
numberOfGenerations+=0.5
Printer
Scheduler
Cell (0,0)
Cell (0,1) …
Cell (n-1, n-1)
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix … … …

12. Program’s flow row=0, column=0
while (numberOfGenerations < maximalNumberOfGenerations)
resume(cell (row, column))
if (time to resume printer)
resume (printer)
column=(column+1)%maximalNumberOfColumns
if(column ==0)
row=(row+1)%maximalNumberOfRows
if (row==0 && column==0)
numberOfGenerations+=0.5
Printer
Scheduler
Cell (0,0)
Cell (0,1) …
Cell (n-1, n-1)
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix … … …

13. Program’s flow row=0, column=0
while (numberOfGenerations < maximalNumberOfGenerations)
resume(cell (row, column))
if (time to resume printer)
resume (printer)
column=(column+1)%maximalNumberOfColumns
if(column ==0)
row=(row+1)%maximalNumberOfRows
if (row==0 && column==0)
numberOfGenerations+=0.5
Printer
Scheduler
Cell (0,0)
Cell (0,1) …
Cell (n-1, n-1)
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix … … …

14. Program’s flow row=0, column=0
while (numberOfGenerations < maximalNumberOfGenerations)
resume(cell (row, column))
if (time to resume printer)
resume (printer)
column=(column+1)%maximalNumberOfColumns
if(column ==0)
row=(row+1)%maximalNumberOfRows
if (row==0 && column==0)
numberOfGenerations+=0.5
Printer
Scheduler
Cell (0,0)
Cell (0,1) …
Cell (n-1, n-1)
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix … … …

15. Program’s flow row=0, column=0
while (numberOfGenerations < maximalNumberOfGenerations)
resume(cell (row, column))
if (time to resume printer)
resume (printer)
column=(column+1)%maximalNumberOfColumns
if(column ==0)
row=(row+1)%maximalNumberOfRows
if (row==0 && column==0)
numberOfGenerations+=0.5
Printer
Scheduler
Cell (0,0)
Cell (0,1) …
Cell (n-1, n-1)
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix … … …

16. Program’s flow row=0, column=0
while (numberOfGenerations < maximalNumberOfGenerations)
resume(cell (row, column))
if (time to resume printer)
resume (printer)
column=(column+1)%maximalNumberOfColumns
if(column ==0)
row=(row+1)%maximalNumberOfRows
if (row==0 && column==0)
numberOfGenerations+=0.5
Printer
Scheduler
Cell (0,0)
Cell (0,1) …
Cell (n-1, n-1)
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix … … …

17. Program’s flow row=0, column=0
while (numberOfGenerations < maximalNumberOfGenerations)
resume(cell (row, column))
if (time to resume printer)
resume (printer)
column=(column+1)%maximalNumberOfColumns
if(column ==0)
row=(row+1)%maximalNumberOfRows
if (row==0 && column==0)
numberOfGenerations+=0.5
Printer
Scheduler
Cell (0,0)
Cell (0,1) …
Cell (n-1, n-1)
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix … … …

18. Program’s flow row=0, column=0
while (numberOfGenerations < maximalNumberOfGenerations)
resume(cell (row, column))
if (time to resume printer)
resume (printer)
column=(column+1)%maximalNumberOfColumns
if(column ==0)
row=(row+1)%maximalNumberOfRows
if (row==0 && column==0)
numberOfGenerations+=0.5
Printer
Scheduler
Cell (0,0)
Cell (0,1) …
Cell (n-1, n-1)
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix … … …

19. Program’s flow row=0, column=0
while (numberOfGenerations < maximalNumberOfGenerations)
resume(cell (row, column))
if (time to resume printer)
resume (printer)
column=(column+1)%maximalNumberOfColumns
if(column ==0)
row=(row+1)%maximalNumberOfRows
if (row==0 && column==0)
numberOfGenerations+=0.5
Printer
Scheduler
Cell (0,0)
Cell (0,1) …
Cell (n-1, n-1)
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix … … …

20. Program’s flow row=0, column=0
while (numberOfGenerations < maximalNumberOfGenerations)
resume(cell (row, column))
if (time to resume printer)
resume (printer)
column=(column+1)%maximalNumberOfColumns
if(column ==0)
row=(row+1)%maximalNumberOfRows
if (row==0 && column==0)
numberOfGenerations+=0.5
Printer
Scheduler
Cell (0,0)
Cell (0,1) …
Cell (n-1, n-1)
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix … … …

21. Program’s flow row=0, column=0
while (numberOfGenerations < maximalNumberOfGenerations)
resume(cell (row, column))
if (time to resume printer)
resume (printer)
column=(column+1)%maximalNumberOfColumns
if(column ==0)
row=(row+1)%maximalNumberOfRows
if (row==0 && column==0)
numberOfGenerations+=0.5
Printer
Scheduler
Cell (0,0)
Cell (0,1) …
Cell (n-1, n-1)
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix … … …

22. Program’s flow row=0, column=0
while (numberOfGenerations < maximalNumberOfGenerations)
resume(cell (row, column))
if (time to resume printer)
resume (printer)
column=(column+1)%maximalNumberOfColumns
if(column ==0)
row=(row+1)%maximalNumberOfRows
if (row==0 && column==0)
numberOfGenerations+=0.5
Printer
Scheduler
Cell (0,0)
Cell (0,1) …
Cell (n-1, n-1)
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix … … …

23. Program’s flow row=0, column=0
while (numberOfGenerations < maximalNumberOfGenerations)
resume(cell (row, column))
if (time to resume printer)
resume (printer)
column=(column+1)%maximalNumberOfColumns
if(column ==0)
row=(row+1)%maximalNumberOfRows
if (row==0 && column==0)
numberOfGenerations+=0.5
Printer
Scheduler
Cell (0,0)
Cell (0,1) …
Cell (n-1, n-1)
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix … … …

24. Program’s flow row=0, column=0
while (numberOfGenerations < maximalNumberOfGenerations)
resume(cell (row, column))
if (time to resume printer)
resume (printer)
column=(column+1)%maximalNumberOfColumns
if(column ==0)
row=(row+1)%maximalNumberOfRows
if (row==0 && column==0)
numberOfGenerations+=0.5
Printer
Scheduler
Cell (0,0)
Cell (0,1) …
Cell (n-1, n-1)
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix … … …

25. Program’s flow row=0, column=0
while (numberOfGenerations < maximalNumberOfGenerations)
resume(cell (row, column))
if (time to resume printer)
resume (printer)
column=(column+1)%maximalNumberOfColumns
if(column ==0)
row=(row+1)%maximalNumberOfRows
if (row==0 && column==0)
numberOfGenerations+=0.5
Printer
Scheduler
Cell (0,0)
Cell (0,1) …
Cell (n-1, n-1)
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix … … …

26. Program’s flow row=0, column=0
while (numberOfGenerations < maximalNumberOfGenerations)
resume(cell (row, column))
if (time to resume printer)
resume (printer)
column=(column+1)%maximalNumberOfColumns
if(column ==0)
row=(row+1)%maximalNumberOfRows
if (row==0 && column==0)
numberOfGenerations+=0.5
Printer
Scheduler
Cell (0,0)
Cell (0,1) …
Cell (n-1, n-1)
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix … … …

27. Program’s flow row=0, column=0
while (numberOfGenerations < maximalNumberOfGenerations)
resume(cell (row, column))
if (time to resume printer)
resume (printer)
column=(column+1)%maximalNumberOfColumns
if(column ==0)
row=(row+1)%maximalNumberOfRows
if (row==0 && column==0)
numberOfGenerations+=0.5
Printer
Scheduler
Cell (0,0)
Cell (0,1) …
Cell (n-1, n-1)
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix … … …

28. Program’s flow row=0, column=0
while (numberOfGenerations < maximalNumberOfGenerations)
resume(cell (row, column))
if (time to resume printer)
resume (printer)
column=(column+1)%maximalNumberOfColumns
if(column ==0)
row=(row+1)%maximalNumberOfRows
if (row==0 && column==0)
numberOfGenerations+=0.5
Printer
Scheduler
Cell (0,0)
Cell (0,1) …
Cell (n-1, n-1)
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix … … …

29. Program’s flow row=0, column=0
while (numberOfGenerations < maximalNumberOfGenerations)
resume(cell (row, column))
if (time to resume printer)
resume (printer)
column=(column+1)%maximalNumberOfColumns
if(column ==0)
row=(row+1)%maximalNumberOfRows
if (row==0 && column==0)
numberOfGenerations+=0.5
Printer
Scheduler
Cell (0,0)
Cell (0,1) …
Cell (n-1, n-1)
print matrix
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix … … …

30. Program’s flow row=0, column=0
while (numberOfGenerations < maximalNumberOfGenerations)
resume(cell (row, column))
if (time to resume printer)
resume (printer)
column=(column+1)%maximalNumberOfColumns
if(column ==0)
row=(row+1)%maximalNumberOfRows
if (row==0 && column==0)
numberOfGenerations+=0.5
Printer
Scheduler
Cell (0,0)
Cell (0,1) …
Cell (n-1, n-1)
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix
calculate stage
calculate stage
calculate stage
update matrix
update matrix
update matrix … … …

31. Program’s flow
> ass3 <filename> <length> <width> <t> <K>
<filename> - name of a file contain the initial state of the game board. A series of size <width> of ‘ ‘ and ‘1’ in each line. The file contain <length> lines.
<t> - number of generations
<K> - printing frequency
your array dimensions will be <width>*<length>

32. Program’s flow
When invoked, and using the co-routines mechanism from class, your application will:
Set up: a state array, Length, Width, K, t
Initiate all co-routines:
each cell gets parameters i,j - its indices in the global array
a scheduler gets t, K, Length, and Width as parameters
a printer gets Length and Width as parameters
Initiate an array CORS of pointers to: cell0,0,…,celllength-1,width-1, scheduler, printer 
Transfer control to scheduler

33. Program’s flow
Each cell in CORS array will point directly to the top of the stack of the corresponded co-routine.
You don’t have to implement the co-routine structure as presented in the practical session.
CORS: CO(0,0)
CO(0,1) …
CO(n-1, n-1) CoPrinter CoScheduler
CO(i,j): Function
Flags
SP(i,j)
CORS: SP(0,0)
SP(0,1) …
SP(n-1, n-1)
SP_CoPrinter SP_CoScheduler