rot
c -= b; c ^= rot(b, 4); b += a; \
c ^= b; c -= rot(b,14); \
a ^= c; a -= rot(c,11); \
b ^= a; b -= rot(a,25); \
c ^= b; c -= rot(b,16); \
a ^= c; a -= rot(c,4); \
b ^= a; b -= rot(a,14); \
c ^= b; c -= rot(b,24); \
a -= c; a ^= rot(c, 4); c += b; \
b -= a; b ^= rot(a, 6); a += c; \
c -= b; c ^= rot(b, 8); b += a; \
a -= c; a ^= rot(c,16); c += b; \
b -= a; b ^= rot(a,19); a += c; \
return rot(p, n, h0<h1);