Question

Question 2.4 [5] For the MIPS assembly instructions below, what is the corresponding C statement? 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.

sll \)t0, \(s0, 2 # \)t0 = f * 4

add \(t0, \)s6, \(t0 # \)t0 = &A[f]

sll \(t1, \)s1, 2 # \(t1 = g * 4

add \)t1, \(s7, \)t1 # \(t1 = &B[g]

lw \)s0, 0(\(t0) # f = A[f]

addi \)t2, \(t0, 4

lw \)t0, 0(\(t2)

add \)t0, \(t0, \)s0

sw \(t0, 0(\)t1)

Short answer

The corresponding C code:

f = A[f];
f = A[f+1] + A[f]
B[g] = f;

Step-by-step solution

Define the concept.

The line “f = A[f]” is used for assigning the value of “A[f]” to the “f”. Then the line “f = A[f+1] + A[f]” first does the sum of “A[f+1]” and “A[f]” and then the value of the sum is assigned to the “f”. And “B[g] = f” is used for assigning the value of “f” to the “B[g]”.

Determine the calculation.

The corresponding C code:

f = A[f]; //Initialize the value of “A[f]” to the “f”.
f = A[f+1] + A[f] // Initialize the value of “A[f+1] + A[f]” to the “f”.
B[g] = f; // Initialize the value of “f” to the “B[g]”.

By assuming “f” and “g” are assigned to registers of “$s0”and registers of “$s1” respectively and also assuming that the base address of the “A” and “B” arrays are in registers of “$s6” and registers of “$s7”,