ADD  R0, R6, #4   ;  put the base address of grid into R0
ADD  R1, R0, #3   ;  calculate address of grid[3]
LDR  R2, R1, #0   ;  grid[3]
ADD  R2, R2, #1   ;  grid[3] + 1
STR  R2, R6, #3   ;  x = grid[3] + 1;
   
AND  R2, R2, #0   ;   
ADD  R2, R2, #5   ;  R2 = 5
ADD  R0, R6, #4   ;  put the base address of grid into R0
ADD  R1, R0, #6   ;  calculate address of grid[6]
STR  R2, R1, #0   ;  grid[6] = 5;