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, 13) :
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
13
1
0
0
1
1
11
13
1
0
0
1
2
1
1
1
1
1
1
14
12
7
6
2
1
↔
11
7
6
1
0
10
1
8
6
8
6
5
Even
Even
4
3
3
5
1
4
3
7
6
4
0
11
9
11
9
2
24
20
12
10
4
2
1
12
10
7
6
1
1
Even
Even
6
5
5
1
1
6
5
7
6
0
6
1
1
6
5
7
6
0
7
1
1
6
5
7
6
0
(6)(11) - (5)(13) = 1