GATE CSE 1992 | Question: 3,i

Question

Write short answers to the following:

1. Which of the following macros can put a macro assembler into an infinite loop?

.MACRO M1,X .IF EQ,X M1 X+1 .ENDC .IF NE,X .WORD X .ENDC .ENDM

.MACRO M2,X .IF EQ,X M2 X .ENDC .IF NE,X .WORD X+1 .ENDC .ENDM

Give an example call that does so.

Comments

plz solve this

---

Macro M1,x

EndM

that means, M1 is a Macro with x as a parameter, ENDM means Macro end.

 

IF EQ,x

ENDC

that means, if condition. EQ,x ... checking x is equal to Something or not ?

 

what M1(x) is doing ? 

checking x is equal to value in the Accumulator, if so, call M1(x+1)

 

what M2(x) is doing ? 

checking x is equal to value in the Accumulator, if so, call M2(x), So this may lead to Infinite loop when if condtion true.

---

Is this in the syllabus still for GATE 2024??

Answer 1

Macro $M_2$ can put the macro assembler into an infinite loop when called with $M_2(0)$

$(EQ(X)$ is TRUE when $X = 0)$

For $M_1$ the argument $X$ is incremented for the recursive call and so the macro expansion will happen maximum $2$ times.

Comments

Source for this???

---

Why is   

(EQ(X)  TRUE when X=0)   

why is it true for x=0 not for x=1

---

@svas7246, is assembler concept in 2022 syllabus?