From 88cd41d7355a3528e43c5a6754da59228c048dc9 Mon Sep 17 00:00:00 2001 From: Mattias Andrée Date: Wed, 1 Jun 2016 19:38:15 +0200 Subject: Manual: division algorithm MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Signed-off-by: Mattias Andrée --- doc/arithmetic.tex | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) (limited to 'doc') diff --git a/doc/arithmetic.tex b/doc/arithmetic.tex index e2dd142..4601a7a 100644 --- a/doc/arithmetic.tex +++ b/doc/arithmetic.tex @@ -223,7 +223,7 @@ lend you a hand. \noindent Now to the weird ones that will more often than -not award you a face-slap. % Hade positive punishment +not award you a face-slap. % Had positive punishment % been legal or even mildly pedagogical. But I would % not put it past Coca-Cola. @@ -306,7 +306,19 @@ not award you a face-slap. % Hade positive punishment \} \end{alltt} -% TODO zdivmod's algorithm +Currently, libzahl uses an almost trivial division +algorithm. It operates on positive numbers. It begins +by left-shifting the divisor as must as possible with +letting it exceed the dividend. Then, it subtracts +the shifted divisor from the dividend and add 1, +left-shifted as much as the divisor, to the quotient. +The quotient begins at 0. It then right-shifts +the shifted divisor as little as possible until +it no longer exceeds the diminished dividend and +marks the shift in the quotient. This process is +repeated on till the unshifted divisor is greater +than the diminished dividend. The final diminished +dividend is the remainder. -- cgit v1.2.3-70-g09d2