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, 10) :
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
10
1
0
0
1
1
10
↔
11
0
1
1
0
1
5
10
12
5
6
2
5
↔
11
5
6
1
0
6
1
6
6
6
6
3
Even
Even
3
3
3
3
5
3
3
5
6
2
1
8
9
8
9
1
18
20
9
10
4
1
↔
3
9
10
3
3
2
1
12
13
2
2
1
Even
Even
1
1
5
1
1
1
1
9
10
0
6
1
1
1
1
9
10
0
7
1
1
1
1
9
10
0
(1)(11) - (1)(10) = 1