SPOC 练习题

os

• 执行 ./x86.py -p loop.s -t 1 -i 100 -R dx， 请问dx的值是什么？

dx          Thread 0         
  0   
-1   1000 sub  $1,%dx
-1   1001 test $0,%dx
-1   1002 jgte .top
-1   1003 halt

• 执行 ./x86.py -p loop.s -t 2 -i 100 -a dx=3,dx=3 -R dx ， 请问dx的值是什么？

   dx          Thread 0                Thread 1         
    3   
    2   1000 sub  $1,%dx
    2   1001 test $0,%dx
    2   1002 jgte .top
    1   1000 sub  $1,%dx
    1   1001 test $0,%dx
    1   1002 jgte .top
    0   1000 sub  $1,%dx
    0   1001 test $0,%dx
    0   1002 jgte .top
   -1   1000 sub  $1,%dx
   -1   1001 test $0,%dx
   -1   1002 jgte .top
   -1   1003 halt
    3   ----- Halt;Switch -----  ----- Halt;Switch -----  
    2                            1000 sub  $1,%dx
    2                            1001 test $0,%dx
    2                            1002 jgte .top
    1                            1000 sub  $1,%dx
    1                            1001 test $0,%dx
    1                            1002 jgte .top
    0                            1000 sub  $1,%dx
    0                            1001 test $0,%dx
    0                            1002 jgte .top
   -1                            1000 sub  $1,%dx
   -1                            1001 test $0,%dx
   -1                            1002 jgte .top
   -1                            1003 halt

• 执行 ./x86.py -p loop.s -t 2 -i 3 -r -a dx=3,dx=3 -R dx， 请问dx的值是什么？

  dx          Thread 0                Thread 1         
  3   
  2   1000 sub  $1,%dx
  3   ------ Interrupt ------  ------ Interrupt ------  
  2                            1000 sub  $1,%dx
  2                            1001 test $0,%dx
  2   ------ Interrupt ------  ------ Interrupt ------  
  2   1001 test $0,%dx
  2   1002 jgte .top
  1   1000 sub  $1,%dx
  2   ------ Interrupt ------  ------ Interrupt ------  
  2                            1002 jgte .top
  1   ------ Interrupt ------  ------ Interrupt ------  
  1   1001 test $0,%dx
  1   1002 jgte .top
  0   1000 sub  $1,%dx
  2   ------ Interrupt ------  ------ Interrupt ------  
  1                            1000 sub  $1,%dx
  1                            1001 test $0,%dx
  1                            1002 jgte .top
  0   ------ Interrupt ------  ------ Interrupt ------  
  0   1001 test $0,%dx
  0   1002 jgte .top
-1   1000 sub  $1,%dx
1   ------ Interrupt ------  ------ Interrupt ------  
0                            1000 sub  $1,%dx
0                            1001 test $0,%dx
-1   ------ Interrupt ------  ------ Interrupt ------  
-1   1001 test $0,%dx
-1   1002 jgte .top
-1   1003 halt
0   ----- Halt;Switch -----  ----- Halt;Switch -----  
0   ------ Interrupt ------  ------ Interrupt ------  
0                            1002 jgte .top
-1                            1000 sub  $1,%dx
-1   ------ Interrupt ------  ------ Interrupt ------  
-1                            1001 test $0,%dx
-1                            1002 jgte .top
-1   ------ Interrupt ------  ------ Interrupt ------  
-1                            1003 halt

• 变量x的内存地址为2000, ./x86.py -p looping-race-nolock.s -t 1 -M 2000, 请问变量x的值是什么？

2000      bx          Thread 0         
  0       0   
  0       0   1000 mov 2000, %ax
  0       0   1001 add $1, %ax
  1       0   1002 mov %ax, 2000
  1      -1   1003 sub  $1, %bx
  1      -1   1004 test $0, %bx
  1      -1   1005 jgt .top
  1      -1   1006 halt

• 变量x的内存地址为2000, ./x86.py -p looping-race-nolock.s -t 2 -a bx=3 -M 2000, 请问变量x的值是什么？为何每个线程要循环3次？

• 变量x的内存地址为2000, ./x86.py -p looping-race-nolock.s -t 2 -M 2000 -i 4 -r -s 0， 请问变量x的值是什么？

   dx          Thread 0                Thread 1         
    3   
    2   1000 sub  $1,%dx
    3   ------ Interrupt ------  ------ Interrupt ------  
    2                            1000 sub  $1,%dx
    2                            1001 test $0,%dx
    2   ------ Interrupt ------  ------ Interrupt ------  
    2   1001 test $0,%dx
    2   1002 jgte .top
    1   1000 sub  $1,%dx
    2   ------ Interrupt ------  ------ Interrupt ------  
    2                            1002 jgte .top
    1   ------ Interrupt ------  ------ Interrupt ------  
    1   1001 test $0,%dx
    1   1002 jgte .top
    2   ------ Interrupt ------  ------ Interrupt ------  
    1                            1000 sub  $1,%dx
    1                            1001 test $0,%dx
    1   ------ Interrupt ------  ------ Interrupt ------  
    0   1000 sub  $1,%dx
    1   ------ Interrupt ------  ------ Interrupt ------  
    1                            1002 jgte .top
    0   ------ Interrupt ------  ------ Interrupt ------  
    0   1001 test $0,%dx
    0   1002 jgte .top
   -1   1000 sub  $1,%dx
    1   ------ Interrupt ------  ------ Interrupt ------  
    0                            1000 sub  $1,%dx
    0                            1001 test $0,%dx
   -1   ------ Interrupt ------  ------ Interrupt ------  
   -1   1001 test $0,%dx
   -1   1002 jgte .top
    0   ------ Interrupt ------  ------ Interrupt ------  
    0                            1002 jgte .top
   -1   ------ Interrupt ------  ------ Interrupt ------  
   -1   1003 halt
    0   ----- Halt;Switch -----  ----- Halt;Switch -----  
   -1                            1000 sub  $1,%dx
   -1                            1001 test $0,%dx
   -1   ------ Interrupt ------  ------ Interrupt ------  
   -1                            1002 jgte .top
   -1                            1003 halt

• 变量x的内存地址为2000, ./x86.py -p looping-race-nolock.s -t 2 -M 2000 -i 4 -r -s 1， 请问变量x的值是什么？

2000      bx          Thread 0                Thread 1         
  0       0   
  0       0   1000 mov 2000, %ax
  0       0   1001 add $1, %ax
  0       0   ------ Interrupt ------  ------ Interrupt ------  
  0       0                            1000 mov 2000, %ax
  0       0                            1001 add $1, %ax
  0       0   ------ Interrupt ------  ------ Interrupt ------  
  1       0   1002 mov %ax, 2000
  1      -1   1003 sub  $1, %bx
  1      -1   1004 test $0, %bx
  1       0   ------ Interrupt ------  ------ Interrupt ------  
  1       0                            1002 mov %ax, 2000
  1      -1   ------ Interrupt ------  ------ Interrupt ------  
  1      -1   1005 jgt .top
  1      -1   1006 halt
  1       0   ----- Halt;Switch -----  ----- Halt;Switch -----  
  1       0   ------ Interrupt ------  ------ Interrupt ------  
  1      -1                            1003 sub  $1, %bx
  1      -1                            1004 test $0, %bx
  1      -1   ------ Interrupt ------  ------ Interrupt ------  
  1      -1                            1005 jgt .top
  1      -1                            1006 halt

• 变量x的内存地址为2000, ./x86.py -p looping-race-nolock.s -t 2 -M 2000 -i 4 -r -s 2， 请问变量x的值是什么？

2000      bx          Thread 0                Thread 1         
  0       0   
  0       0   1000 mov 2000, %ax
  0       0   1001 add $1, %ax
  1       0   1002 mov %ax, 2000
  1      -1   1003 sub  $1, %bx
  1       0   ------ Interrupt ------  ------ Interrupt ------  
  1       0                            1000 mov 2000, %ax
  1       0                            1001 add $1, %ax
  1      -1   ------ Interrupt ------  ------ Interrupt ------  
  1      -1   1004 test $0, %bx
  1      -1   1005 jgt .top
  1       0   ------ Interrupt ------  ------ Interrupt ------  
  2       0                            1002 mov %ax, 2000
  2      -1                            1003 sub  $1, %bx
  2      -1                            1004 test $0, %bx
  2      -1   ------ Interrupt ------  ------ Interrupt ------  
  2      -1   1006 halt
  2      -1   ----- Halt;Switch -----  ----- Halt;Switch -----  
  2      -1                            1005 jgt .top
  2      -1                            1006 halt

• 变量x的内存地址为2000, ./x86.py -p looping-race-nolock.s -a bx=1 -t 2 -M 2000 -i 1， 请问变量x的值是什么？

2000      bx          Thread 0                Thread 1         
  0       1   
  0       1   1000 mov 2000, %ax
  0       1   ------ Interrupt ------  ------ Interrupt ------  
  0       1                            1000 mov 2000, %ax
  0       1   ------ Interrupt ------  ------ Interrupt ------  
  0       1   1001 add $1, %ax
  0       1   ------ Interrupt ------  ------ Interrupt ------  
  0       1                            1001 add $1, %ax
  0       1   ------ Interrupt ------  ------ Interrupt ------  
  1       1   1002 mov %ax, 2000
  1       1   ------ Interrupt ------  ------ Interrupt ------  
  1       1                            1002 mov %ax, 2000
  1       1   ------ Interrupt ------  ------ Interrupt ------  
  1       0   1003 sub  $1, %bx
  1       1   ------ Interrupt ------  ------ Interrupt ------  
  1       0                            1003 sub  $1, %bx
  1       0   ------ Interrupt ------  ------ Interrupt ------  
  1       0   1004 test $0, %bx
  1       0   ------ Interrupt ------  ------ Interrupt ------  
  1       0                            1004 test $0, %bx
  1       0   ------ Interrupt ------  ------ Interrupt ------  
  1       0   1005 jgt .top
  1       0   ------ Interrupt ------  ------ Interrupt ------  
  1       0                            1005 jgt .top
  1       0   ------ Interrupt ------  ------ Interrupt ------  
  1       0   1006 halt
  1       0   ----- Halt;Switch -----  ----- Halt;Switch -----  
  1       0   ------ Interrupt ------  ------ Interrupt ------  
  1       0                            1006 halt