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, 8) :
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
8
1
0
0
1
1
8
↔
11
0
1
1
0
3
4
8
12
4
6
2
4
↔
11
4
6
1
0
7
2
Even
Even
2
3
3
2
↔
11
2
3
1
0
9
1
10
14
5
7
4
1
↔
11
5
7
1
0
10
1
6
7
6
7
5
14
18
7
9
5
5
1
7
9
5
7
4
0
12
16
4
5
2
12
16
6
8
6
2
1
6
8
5
7
1
1
Even
Even
3
4
7
1
1
3
4
5
7
0
(3)(11) - (4)(8) = 1