Please I really need your help and explanations in this one. Thanks Evaluate a s
ID: 3664921 • Letter: P
Question
Please I really need your help and explanations in this one. Thanks
Evaluate a short algebraic expression using code with three-operand instructions. The expression should have a minimum of three operands and 2 operators. Operands may be alpha or numeric.
You may only use registers A through F, plus X and T.
Registers A through F may not be changed, i.e. their values are fixed.
Register T may be used as a temporary register, and Register X must contain the final answer.
Show the postfix for the expression, and then use a stack to evaluate the expression.
Explanation / Answer
An example, consider X=A +B + C * D
The three-operand instructions would be:
ADD X, A, B
MUL T, C, D
ADD X, X, T
The Postfix would be AB+CD*+
The stack would be:
PUSH / A onto the stack
PUSH / B onto the stack
ADD /pop A & B, add them, and push the answer back on the stack
PUSH /C
PUSH / D
MUL /pop C & D, multiply them, and push the answer back on the stack
ADD / pop X & T, add them, and push the answer back on the stack
POP / X off the stack