quarter-round ( a b c d -- a' b' c' d' )


Vocabulary
crypto.chacha20.private

Inputs
aan object
ban object
can object
dan object


Outputs
a'an object
b'an object
c'an object
d'an object


Definition
USING: math math.bitwise ;

IN: crypto.chacha20.private

:: quarter-round ( a b c d -- a' b' c' d' )
a b w+ :> w! d w bitxor 16 bitroll-32 :> z! c z w+
:> y! b y bitxor 12 bitroll-32 :> x! w x w+ w! z w bitxor
8 bitroll-32 z! y z w+ y! x y bitxor 7 bitroll-32 x! w x y z
;