CMP & Flags

Comparison and the Flags Register

The cmp instruction compares two values by subtracting them, but discards the result -- it only sets the flags:

cmp rax, rbx       ; computes rax - rbx, sets flags

The Flags Register

After cmp or arithmetic, these flags are set:

TEST Instruction

test performs a bitwise AND and sets flags (discards result):

test rax, rax      ; sets ZF=1 if rax is zero

This is the idiomatic way to check if a register is zero.

Conditional Jumps After CMP

After cmp a, b:

Your Task

Compare numbers and print the result. For each comparison, print "Y" if true, "N" if false:

1. Is 5 == 5? (Y)
2. Is 3 > 7? (N)
3. Is 2 < 9? (Y)

Print: "Y\nN\nY\n"