Write the LEGv8 assembly code for the following loop. This code compares two cha

Question

Write the LEGv8 assembly code for the following loop. This code compares two character arrays and sets the variable different to 1 if they are not the same // A and B are arrays of characters Cunsigned, 8-bits per element). int different = 0; int index = 0; while(11) != B[index]){ if(A[index] break; if(A[index] different = 1; ''){ == break; index++; Assume different is in X9, the base address of A is in X10 and the base address of B is in X11; index should go in X12 Label Instruction Description Initialize the value of 'different Initialize the value of 'index

Explanation / Answer

Here is the completed code with comments, let me know if you have any doubts

LEGv8.asm

MOV X9, #0 ;initialise X9 (different) with 0
MOV X12, #0 ;initialise X12 (index) with 0

LOOP:
ADD X13, X10, X12 ;Add the index(X12) to X10(Base address of A) and store this in X13(A_i)
ADD X14, X11, X12 ;Add the index(X12) to X11(Base address of B) and store this in X14(B_i)
LDUR X13, [X13] ;Load the contents of X13 into the register X13
LDUR X14, [X14] ;Load the contents of X14 into the register X14
SUBS X15, X13, X14 ;Compute the difference of X13 and X14 while also setting flags
BEQ SECONDIF ;If the zero flag is set(A_i and B_i are equal ) branch to SECONDIF
MOV X9, #1 ;Set different to 1
B EXIT ;Branch to EXIT

SECONDIF:
CBZ X13, EXIT ;Compare if X13 contains 0, if it does, jump to EXIT
ADDI X12, X12, #1 ;Add 1 to X12
B LOOP ;Branch to LOOP

EXIT:

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