1. For the following MIPS assembly instructions above, what is a corresponding C statement? f, g, h and i are assigned to registers $s0, $s1, $s2 and $s3, respectively

add  f, g, h

add  f, i, f

2. For the following C statement, what is the corresponding MIPS assembly code? Assume that the             variables i, and j are assigned to registers $s3, and $s4, respectively. Assume that the base address of the arrays A and B are in registers $s6 and $s7, respectively.

B[8] = A[i − j];

5 Translate the following MIPS code to C. Assume that the variables f, g, h, i, and j are assigned to       registers $s0, $s1, $s2, $s3, and $s4, respectively. Assume that the base address of the arrays A and B are in registers $s6 and $s7, respectively.

addi $t0, $s6, 4

add  $t1, $s6, $0

sw   $t1, 0($t0)

lw   $t0, 0($t0)

add  $s0, $t1, $t0

6    Assume that registers $s0 and $s1 hold the values 0x80000000 and 0xD0000000, respectively.

a.   What is the value of $t0 for the following assembly code?

add $t0, $s0, $s1

b.   Is the result in $t0 the desired result, or has there been overflow?

c. For the contents of registers $s0 and $s1 as specified above, what is the value of $t0 for the following assembly code?

sub $t0, $s0, $s1

d.   Is the result in $t0 the desired result, or has there been overflow?

7    Provide the type and hexadecimal representation of following instruction:

sw $t1, 32($t2)

8    Find the MIPS instructions that extracts bits 16 down to 11 from register $t0 and uses the value of this field to replace bits 31 down to 26 in register $t1 without changing the other 26 bits of register $t1.

9 For the following C statement, write a sequence of MIPS assembly instructions that does the identical operation. Assume $t1 = A, $t2 = B, and $s1 is the base address of C.

A = C[0] << 4;

10. Assume $t0 holds the value 0x00101000. What is the value of $t2 after the following instructions?

slt  $t2, $0, $t0

bne  $t2, $0, ELSE

j    DONE

ELSE: addi $t2, $t2, 2

DONE:

11. Write the MIPS assembly code that creates the 32-bit constant

0010 0000 0000 0001 0100 1001 0010 0100two

and stores that value to register $t1.

Solutions

1. For the following MIPS assembly instructions above, what is a corresponding C statement? f, g, h and i are assigned to registers $s0, $s1, $s2 and $s3, respectively

add  f, g, h

add  f, i, f

f = g + h + i

2. For the following C statement, what is the corresponding MIPS assembly code? Assume that the             variables i, and j are assigned to registers $s3, and $s4, respectively. Assume that the base address of the arrays A and B are in registers $s6 and $s7, respectively.

B[8] = A[i − j];

sub $t0, $s3, $s4

sll    $t0, $t0, 2

add $t1, $s6, $t0

lw $t2, 0($t1)

sw $t2, 32($s7)

3.   Assume that registers $s0 and $s1 hold the values 0x80000000 and 0xD0000000, respectively.

a.   What is the value of $t0 for the following assembly code?

add $t0, $s0, $s1

0x50000000

b.   Is the result in $t0 the desired result, or has there been overflow?

Overflow

c. For the contents of registers $s0 and $s1 as specified above, what is the value of $t0 for the following assembly code?

sub $t0, $s0, $s1

B0000000

d.   Is the result in $t0 the desired result, or has there been overflow?

no overflow

4.   Provide the type and hexadecimal representation of following instruction:

sw $t1, 32($t2)

i-type, 0xAD490020

5. Translate the following MIPS code to C. Assume that the variables f, g, h, i, and j are assigned to       registers $s0, $s1, $s2, $s3, and $s4, respectively. Assume that the base address of the arrays A and B are in registers $s6 and $s7, respectively.

addi $t0, $s6, 4

add  $t1, $s6, $0

sw   $t1, 0($t0)

lw   $t0, 0($t0)

add  $s0, $t1, $t0

f = 2*(&A);

6.   Find a sequence of MIPS instructions that extracts bits 16 down to 11 from register $t0 and uses the value of this field to replace bits 31 down to 26 in register $t1 without changing the other 26 bits of register $t1.

srl $t0, $t0, 11

sll $t0, $t0, 26

ori $t2, $0, 0x03ff

sll $t2, $t2, 16

ori $t2, $t2, 0xffff