xorl %eax – Instruction set architecture in IA-32

It’s probably:

xorl %ebx, %ebx

This is a common idiom for zeroing a register on x86. This would correspond with i = 0 in the C code.

If you are curious “but why ?” the short answer is that the xor instruction is fewer bytes than mov $0, %ebx. The long answer includes other subtle reasons.

I am leaving out the rest of the exercise since there’s nothing idiosyncratic left.

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