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5 . 7 . 3
X O R O p e r a t i o n w i t h P + Q R A I D - 6
F i g u r e 5 9
e x a m p l e , t h e r e a r e f o u r b l o c k s o f s o u r c e d a t a t o h a v e a P + Q R A I D - 6 f u n c t i o n
p e r f o r m e d o n t h e m . T h e i n t e r m e d i a t e r e s u l t i s k e p t b y t h e P a n d Q s t o r e q u e u e s i n t h e
A D M A b e f o r e b e i n g w r i t t e n b a c k t o l o c a l m e m o r y . T h e s o u r c e d a t a i s l o c a t e d a t
a d d r e s s e s 0 A 0 0 0 0 4 0 0 H , 0 A 0 0 0 0 8 0 0 H , 0 A 0 0 0 0 C 0 0 H a n d 0 A 0 0 0 1 0 0 0 H
r e s p e c t i v e l y .
A l l d a t a t r a n s f e r s n e e d e d f o r t h i s o p e r a t i o n a r e c o n t r o l l e d b y c h a i n d e s c r i p t o r s l o c a t e d
i n l o c a l m e m o r y . T h e A p p l i c a t i o n D M A a s a m a s t e r o n t h e i n t e r n a l b u s i n i t i a t e s a d a t a
t r a n s f e r . T h e a l g o r i t h m i s i m p l e m e n t e d s u c h t h a t a s d a t a i s r e a d f r o m l o c a l m e m o r y ,
t h e A D M A e x e c u t e s t h e X O R o p e r a t i o n t o g e n e r a t e P , a n d a p p l i e s t h e G F M u l t i p l y
f u n c t i o n t o t h e i n c o m i n g s o u r c e d a t a f o l l o w e d b y t h e X O R o p e r a t i o n t o g e n e r a t e Q .
O n l y a s i n g l e d e s c r i p t o r i s r e q u i r e d a n d g e n e r a t e s b o t h c h e c k v a l u e s . E a c h d e s c r i p t o r i s
p r o c e s s e d a s i l l u s t r a t e d i n
N o t e :
O p t i o n a l l y , t h e u s e r m a y d i s a b l e t h e g e n e r a t i o n o f P w h i l e g e n e r a t i n g Q .
F i g u r e 5 9 . T h e P + Q R A I D 6 M o d e A l g o r i t h m
b i t w i s e - X O R
( 6 4 - b i t w i d e )
b i t w i s e - X O R
( 6 4 - b i t w i d e )
b i t w i s e - X O R
( 6 4 - b i t w i d e )
b y t e 8
®
I n t e l
8 1 3 4 1 a n d 8 1 3 4 2 I / O P r o c e s s o r s
D e v e l o p e r ' s M a n u a l
4 9 4
d e s c r i b e s t h e X O R w i t h P + Q R A I D - 6 i m p l e m e n t a t i o n . I n t h i s i l l u s t r a t i v e
F i g u r e 5 9
M S B
G F M u l t i p l y
D M L T 1 = 0 1
B l o c k 1
1 0 2 4 b y t e s
G F M u l t i p l y
D M L T 2 = 0 2
B l o c k 2
1 0 2 4 b y t e s
G F M u l t i p l y
D M L T 3 = 0 4
B l o c k 3
1 0 2 4 b y t e s
G F M u l t i p l y
D M L T 3 = 0 8
B l o c k 4
1 0 2 4 b y t e s
b y t e 1
. . .
. . .
. . .
Q R e s u l t
S A R 0 = 0 1 0 0 0 0 0 0 A 0 0 0 0 4 0 0 H
S A R 1 = 0 2 0 0 0 0 0 0 A 0 0 0 0 8 0 0 H
S A R 2 = 0 4 0 0 0 0 0 0 A 0 0 0 0 C 0 0 H
S A R 3 = 0 8 0 0 0 0 0 0 A 0 0 0 1 0 0 0 H
P _ D e s t i n a t i o n = 0 B 0 0 0 0 8 0 0 H
Q _ D e s t i n a t i o n = 0 B 0 0 0 0 4 0 0 H
®
I n t e l
8 1 3 4 1 a n d 8 1 3 4 2 — A p p l i c a t i o n D M A U n i t
L o c a l M e m o r y
b y t e s 1 - 8
b y t e s 1 - 8
b y t e s 1 - 8
b y t e s 1 - 8
b y t e 8
0 B 0 0 0 0 4 0 0 H
0 B 0 0 0 0 8 0 0 H
1 K b y t e
1 2 8 - D e e p
S t o r e Q u e u e s
C o n t r o l R e g i s t e r V a l u e s
A B C R = 0 0 0 0 0 4 0 0 H
A D C R = 0 0 0 4 0 0 1 F H
L S B
0 A 0 0 0 0 4 0 0 H
0 A 0 0 0 0 8 0 0 H
0 A 0 0 0 0 C 0 0 H
0 A 0 0 0 1 0 0 0 H
b y t e 1
. . .
. . .
. . .
P R e s u l t
N o t e : P _ D e s t i n a t i o n
a n d Q _ D e s t i n a t i o n
S h a r e t h e s a m e
U p p e r A d d r e s s
B 6 2 2 8 - 0 1
D e c e m b e r 2 0 0 7
O r d e r N u m b e r : 3 1 5 0 3 7 - 0 0 2 U S
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