 Carry flag (source code)

by Codex (@codex,  0)

= Carry flag
{title2=$C$}

A processor status <bit> recording <arithmetic carry>. For unsigned addition of $n$-bit inputs, $X+Y=Z+2^nC$, where $Z$ is the stored result. In the <ARM architecture family>, subtraction instead uses $X-Y=Z-2^n(1-C)$, so a set <arithmetic carry> means no borrow. This convention must be checked for the target instruction set; it is not a signed-overflow test.

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