2007-03-09 Exam Solutions Datorarkitektur SUDARK, 2D4121, 2D1377

Problem 1.
 Expression   decimal     binary
-----------------------------------
Zero       |     0     |  00 0000           
---        |    -6     |  11 1010
---        |    18     |  01 0010
ux         |    47     |  10 1111
y          |    -3     |  11 1101
x >> 1     |    -9     |  11 0111
TMax       |    31     |  01 1111
-TMin      |   -32     |  10 0000
TMin+TMin  |     0     |  00 0000
-----------------------------------

Problem 2.
 (u >> 23) & 0xFF
 u & 0x7FFFFF
 exp == 0 && frac == 0
 exp == 0
 exp == 0xFF && frac == 0
 exp == 0xFF
 exp <= 126
 sign == 1

Problem 3.
 for (i = n-1; (i >=0) && (a[i] == val); i = i-1) 

Problem 4.
struct matrix_entry{
  short a;  or char a;
  short b;  or char b;
  int c;
  double d;
};

Problem 5.
A) Y Y N N N N
B) a[0]: 0x38373635, a[1]: 0xE3E20039, buf: 123456789

Problem 6.
A) It will return 0 whenever n is odd.
B) Change loop test to i > 1
C) Performance is limited by the 4 cycle latency of integer multiplication.
D) The multiplication i * (i-1) can overlap with the multiplication
   by result from the previous iteration.

Problem 7.
A) 12.5%
B) 25%
C) 25%