X =
00
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
Y =
00
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
X ↔ Y
Ext-GCD(11, 9) :
i
GCD
Bezout
AOdd :
AEven :
A
↔
B
ax
ay
bx
by
|A-B|
A↔B
Sx
Sy
ax ←
Sx' ay ←
Sy' A ←
A/2 ax ←
ax + Y ay ←
ay + X ax ←
ax/2 ay ←
ay/2
0
11
9
1
0
0
1
1
11
9
1
0
0
1
2
0
1
1
1
1
1
10
12
5
6
2
1
9
5
6
0
1
8
1
5
7
5
7
4
14
18
7
9
3
4
↔
1
7
9
5
6
3
2
16
20
8
10
4
2
↔
1
8
10
5
6
1
1
Even
Even
4
5
5
1
↔
1
4
5
5
6
0
6
1
↔
1
4
5
5
6
0
7
1
1
5
6
4
5
0
(5)(11) - (6)(9) = 1