Consider evaluating the following expression tree on a machine with load-store architecture in which memory can be accessed only through load and store instructions. The variables a,b,c,d and e are initially stored in memory. The binary operators used in this expression tree can be evaluated by the machine only when operands are in registers. The instructions produce result only in a register. If no intermediate results can be stored in memory, what is the minimum number of registers needed to evaluate this expression?a)2b)9c)5d)3Correct answer is option 'D'. Can you explain this answer? - EduRev Computer Science Engineering (CSE) Question

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Consider evaluating the following expression tree on a machine with load-store architecture in which memory can be accessed only through load and store instructions. The variables a,b,c,d and e are initially stored in memory. The binary operators used in this expression tree can be evaluated by the machine only when operands are in registers. The instructions produce result only in a register. If no intermediate results can be stored in memory, what is the minimum number of registers needed to evaluate this expression?

a)
2
b)
9
c)
5
d)
3

Correct answer is option 'D'. Can you explain this answer?

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Consider evaluating the following expression tree on a machine with lo...

Given is Load Store Architecture, that means we can access memory using Load and Store Instructions.

Key Idea:- Pick new register only when it is required.

We want to add c and d, and initially both are in memory, therefore copy these into registers.

(here no compensation can be done, we need two registers)

(at this point R1 is holding c+d and R2 is holding d, i.e.

Now, e comes into picture and my question is, Can i make use of R1 or R2 to store e ?
I can not use R1 to store e as its value will be needed later but I can use R2.

Doing this all gives, final value of right sub-tree is stored in R1, and R2 stores e.
Now, coming to left subtree, to perform "a-b" we need to copy both variables in registers.
We can copy one of the variable in R2, but we can not obviously copy in R1 as value of R1 will be required later.

Load R2, a

Load R3, b (here comes extra register, and we can not avoid using it.)

Current mapping is

and R1 contains final value of Right subtree.

Hence 3

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Consider evaluating the following expression tree on a machine with load-store architecture in which memory can be accessed only through load and store instructions. The variables a,b,c,d and e are initially stored in memory. The binary operators used in this expression tree can be evaluated by the machine only when operands are in registers. The instructions produce result only in a register. If no intermediate results can be stored in memory, what is the minimum number of registers needed to evaluate this expression?a)2b)9c)5d)3Correct answer is option 'D'. Can you explain this answer?

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Consider evaluating the following expression tree on a machine with load-store architecture in which memory can be accessed only through load and store instructions. The variables a,b,c,d and e are initially stored in memory. The binary operators used in this expression tree can be evaluated by the machine only when operands are in registers. The instructions produce result only in a register. If no intermediate results can be stored in memory, what is the minimum number of registers needed to evaluate this expression?a)2b)9c)5d)3Correct answer is option 'D'. Can you explain this answer? for Computer Science Engineering (CSE) 2024 is part of Computer Science Engineering (CSE) preparation. The Question and answers have been prepared according to the Computer Science Engineering (CSE) exam syllabus. Information about Consider evaluating the following expression tree on a machine with load-store architecture in which memory can be accessed only through load and store instructions. The variables a,b,c,d and e are initially stored in memory. The binary operators used in this expression tree can be evaluated by the machine only when operands are in registers. The instructions produce result only in a register. If no intermediate results can be stored in memory, what is the minimum number of registers needed to evaluate this expression?a)2b)9c)5d)3Correct answer is option 'D'. Can you explain this answer? covers all topics & solutions for Computer Science Engineering (CSE) 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Consider evaluating the following expression tree on a machine with load-store architecture in which memory can be accessed only through load and store instructions. The variables a,b,c,d and e are initially stored in memory. The binary operators used in this expression tree can be evaluated by the machine only when operands are in registers. The instructions produce result only in a register. If no intermediate results can be stored in memory, what is the minimum number of registers needed to evaluate this expression?a)2b)9c)5d)3Correct answer is option 'D'. Can you explain this answer?.

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