WinMUGEN's Exponentiation Operator Bug

Instead of computing 2**n correctly, WinMUGEN misinterprets the binary representation of n by reading its least significant bits in reverse order. This causes it to apply the exponentiation as if the bit order of the exponent were flipped, resulting in values being misrouted to unexpected positions. This was fixed on MUGEN 1.0 RC2 onwards. Let's see their results with this table.

Expression Expected Output MUGEN Output Status
2 ** 0 0b00000000000000000000000000000001
1		 0b00000000000000000000000000000001
1		 ✔
Match
2 ** 1 0b00000000000000000000000000000010
2		 0b00000000000000000000000000000010
2		 ✔
Match
2 ** 2 0b00000000000000000000000000000100
4		 0b00000000000000000000000000000100
4		 ✔
Match
2 ** 3 0b00000000000000000000000000001000
8		 0b00000000000000000000000000001000
8		 ✔
Match
2 ** 4 0b00000000000000000000000000010000
16		 0b00000000000000000000000000010000
16		 ✔
Match
2 ** 5 0b00000000000000000000000000100000
32		 0b00000000000000000000000001000000
64		 ✘ Mismatch
2 ** 6 0b00000000000000000000000001000000
64		 0b00000000000000000000000000100000
32		 ✘ Mismatch
2 ** 7 0b00000000000000000000000010000000
128		 0b00000000000000000000000010000000
128		 ✔
Match
2 ** 8 0b00000000000000000000000100000000
256		 0b00000000000000000000000100000000
256		 ✔
Match
2 ** 9 0b00000000000000000000001000000000
512		 0b00000000000000000001000000000000
4096		 ✘ Mismatch
2 ** 10 0b00000000000000000000010000000000
1024		 0b00000000000000000000010000000000
1024		 ✔
Match
2 ** 11 0b00000000000000000000100000000000
2048		 0b00000000000000000100000000000000
16384		 ✘ Mismatch
2 ** 12 0b00000000000000000001000000000000
4096		 0b00000000000000000000001000000000
512		 ✘ Mismatch
2 ** 13 0b00000000000000000010000000000000
8192		 0b00000000000000000010000000000000
8192		 ✔
Match
2 ** 14 0b00000000000000000100000000000000
16384		 0b00000000000000000000100000000000
2048		 ✘ Mismatch
2 ** 15 0b00000000000000001000000000000000
32768		 0b00000000000000001000000000000000
32768		 ✔
Match
2 ** 16 0b00000000000000010000000000000000
65536		 0b00000000000000010000000000000000
65536		 ✔
Match
2 ** 17 0b00000000000000100000000000000000
131072		 0b00000001000000000000000000000000
16777216		 ✘ Mismatch
2 ** 18 0b00000000000001000000000000000000
262144		 0b00000000000100000000000000000000
1048576		 ✘ Mismatch
2 ** 19 0b00000000000010000000000000000000
524288		 0b00010000000000000000000000000000
268435456		 ✘ Mismatch
2 ** 20 0b00000000000100000000000000000000
1048576		 0b00000000000001000000000000000000
262144		 ✘ Mismatch
2 ** 21 0b00000000001000000000000000000000
2097152		 0b00000100000000000000000000000000
67108864		 ✘ Mismatch
2 ** 22 0b00000000010000000000000000000000
4194304		 0b00000000010000000000000000000000
4194304		 ✔
Match
2 ** 23 0b00000000100000000000000000000000
8388608		 0b01000000000000000000000000000000
1073741824		 ✘ Mismatch
2 ** 24 0b00000001000000000000000000000000
16777216		 0b00000000000000100000000000000000
131072		 ✘ Mismatch
2 ** 25 0b00000010000000000000000000000000
33554432		 0b00000010000000000000000000000000
33554432		 ✔
Match
2 ** 26 0b00000100000000000000000000000000
67108864		 0b00000000001000000000000000000000
2097152		 ✘ Mismatch
2 ** 27 0b00001000000000000000000000000000
134217728		 0b00100000000000000000000000000000
536870912		 ✘ Mismatch
2 ** 28 0b00010000000000000000000000000000
268435456		 0b00000000000010000000000000000000
524288		 ✘ Mismatch
2 ** 29 0b00100000000000000000000000000000
536870912		 0b00001000000000000000000000000000
134217728		 ✘ Mismatch
2 ** 30 0b01000000000000000000000000000000
1073741824		 0b00000000100000000000000000000000
8388608		 ✘ Mismatch
2 ** 31 0b10000000000000000000000000000000
-2147483648		 0b10000000000000000000000000000000
-2147483648		 ✔
Match