1. Computer Architecture and Assembly Language
Practical Session 9

2. Game of life
You can see the simulator here. …

3. Game of life
Simulates Evolution of two-dimensional hexagonal 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.

4. Game rules
If the cell is currently alive, then it will remain alive in the next generation if and only if exactly 3 or 4 of its neighbors are currently alive. Otherwise it dies.
Examples:
me stays alive
me stays alive me me me me
A dead cell remains dead in the next generation, unless it has exactly 2 living neighbors.
Example:
me comes alive me me

5. Cell neighbors At the board edgesme 1 2 3 4 5 6
At the board edges
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 6 5 2 3 1

6. Input file Each cell is given an initial state from input file.1
alive cells are denoted by ‘1’ in input file
dead cells are denoted by ‘0’ 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
calculate next state 1
update next state 1 v v x x v x x v x x v v

7. i,j i,j i,j i,j Cell neighbors or i-1, j-1 i-1,j i-1,j i-1,j+1 i, j-12 1 2 or me 6 3 6 me 3 5 4 5 4
i,j
i,j
i-1, j-1
i-1,j
i-1,j
i-1,j+1
i, j-1
i,j
i, j+1
i, j-1
i,j
i, j+1
i+1, j-1
i+1,j
i+1,j
i+1, j+1

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

9. (stage 1) resume  (stage 2) resume
A Cell
Cell can be alive(‘1’) or dead(‘0‘)
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

10. A scheduler The printer implements simple round-robin algorithm
void scheduler (int cycles)
iterate cycles times over all cells
after each P 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??
The printer
Prints the entire “world” (the global array), whenever it gets “time”.

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)
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 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 … … …

32. 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 … … …

33. Program’s flow
> ass3 <filename> <length> <width> <g> <P>
<filename> - name of a file contain the initial state of the game board. A series of size <2*width> of ‘0 ‘ and ‘1’ in each line, separated by space. The file contain <length> lines.
<g> - number of generations
<P> - printing frequency
your array dimensions will be <width>*<length>

34. Program’s flow
When invoked, and using the co-routines mechanism from class, your application will:
Set up: a state array, Length, Width, P, g
Initiate all co-routines:
each cell gets parameters i,j - its indices in the global array
a scheduler gets g, P, 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

35. Program’s flow
You may build cell in CORS array will point directly to the top of the stack of the corresponded co-routine.
CORS: CoPrinter CoScheduler CO(0,0)
CO(0,1) …
CO(i, j) …
CO(i,j): Function
Flags
SP(i,j)
CORS: SP_CoPrinter SP_CoScheduler SP(0,0)
SP(0,1) …
SP(i, j)