Loop to Sum 1 to N

Every for Loop Becomes cmp and jcc

Assembly has no for keyword. Clang emits labels, arithmetic, and conditional jumps. Compiler Explorer is daily reading for this pattern: cmp sets flags, jl/jnz reads them. At -O2, your sum loop may disappear into a closed-form multiply, which is why you learn the naive form first.

nasmCopy
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• cmp / test: set ZF, SF, CF without storing a result
• jl vs jb: signed less vs unsigned below (mixing them is a real bug class)
• Keep hot state in registers; memory traffic is what -O3 tries to eliminate

Summing 1 Through N

For N=100, the accumulator visits every integer once. N=0 should leave the sum at zero without entering the body.

For this exercise, you will sum 1..N entirely in registers; the harness prints the result with sys_write. This task asks you to own the flags-register discipline, because reading optimized assembly and debugging branch-heavy crashes both require it.

Keep the relevant man page, ABI doc, or Rust reference chapter open while you work. When your output disagrees with the reference implementation on the same machine, the mismatch is usually an alignment rule, an off-by-one terminator, or a register slot you misread in GDB.