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Division is truncated, not floored - libzahl - big integer library |
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git clone git://git.suckless.org/libzahl |
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commit bc8390c7615cf9a466420aa05130322488d54d7b |
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parent 437b35efd43f788a1edcf483e623d766642d1c29 |
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Author: Mattias Andrée <[email protected]> |
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Date: Sat, 14 May 2016 20:20:10 +0200 |
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Division is truncated, not floored |
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Signed-off-by: Mattias Andrée <[email protected]> |
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Diffstat: |
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M doc/bit-operations.tex | 17 ++++++++--------- |
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1 file changed, 8 insertions(+), 9 deletions(-) |
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--- |
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diff --git a/doc/bit-operations.tex b/doc/bit-operations.tex |
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@@ -40,15 +40,14 @@ $r = \phantom{0100}100001_2$ after calling {\tt zrsh(r, a, … |
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\vspace{1em} |
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{\tt zlsh(r, a, b)} is equivalent to $r \gets a \cdot 2^b$, |
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-and {\tt zrsh(r, a, b)} is equivalent to |
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-$r \gets \lfloor a \div 2^b \rfloor$, {\tt zlsh} and |
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-{\tt zrsh} are significantly faster than {\tt zpowu} |
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-and should be used whenever possible. {\tt zpowu} |
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-does not check if it is possible for it to use {\tt zlsh} |
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-instead, even if it would, {\tt zlsh} and {\tt zrsh} |
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-would still be preferable in most cases because it |
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-removes the need for {\tt zmul} and {\tt zdiv}, |
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-respectively. |
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+and {\tt zrsh(r, a, b)} is equivalent to $r \gets a \div 2^b$, |
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+with truncated division, {\tt zlsh} and {\tt zrsh} are |
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+significantly faster than {\tt zpowu} and should be used |
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+whenever possible. {\tt zpowu} does not check if it is |
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+possible for it to use {\tt zlsh} instead, even if it |
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+would, {\tt zlsh} and {\tt zrsh} would still be preferable |
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+in most cases because it removes the need for {\tt zmul} |
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+and {\tt zdiv}, respectively. |
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{\tt zlsh} and {\tt zrsh} are implemented in two steps: |
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(1) shift whole characters, that is, groups of aligned |
