Consider the expression (a-1) * ((( b + c ) / 3 )) + d)). Let X be the minimum number of registers required by an optimal code generation (without any register spill) algorithm for a load/store architecture, in which
(i) only load and store instructions can have memory operands and
(ii) arithmetic instructions can have only register or immediate operands
The value of X is ________.
Note : This questions appeared as Numerical Answer Type.
(A) 2
(B) 1
(C) 4
(D) 3
Answer: (A)
Explanation: The assembly code using the load/store architecture can be written as follows:
Load R1, b Load R2, c ADD R1, R2 Div R1, 3 Load R2, d Add R1, R2 Load R2, a Sub R2, 1 Mul R2, R1
Hence minimum 2 registers required.
This explanation is contributed by Sonal Kukreja.