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(6, 11) :
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
6
11
1
0
0
1
1
6
11
1
0
0
1
5
3
12
6
6
3
2
3
11
6
3
0
1
8
1
6
4
6
4
4
Even
Even
3
2
3
4
↔
3
3
2
6
3
1
2
14
8
7
4
4
2
↔
3
7
4
6
3
1
1
18
10
9
5
5
1
↔
3
9
5
6
3
2
1
15
8
4
2
1
Even
Even
2
1
6
1
1
2
1
9
5
0
7
1
1
2
1
9
5
0
(2)(6) - (1)(11) = 1