`XOR[0...n] = 0 ^ 1 .... ^ n = [n, 1, n + 1, 0][n % 4]`
XOR[0...x] = (x&1^(x&2)>>1)+x*(~x&1)
Actually I found something through Gemini based on the table mod 4 idea in previous post. Thanks.
XOR[0...x] = (x&1^(x&2)>>1)+x*(~x&1)