[userbinator]

For x64 under both *nix and Windows sizeof(int) remains at 4 while the sizes of pointers increase to 8 bytes (64 bits), so anything in the compiler that depends on those sizes would also have to change. As for the opcodes, with x86/x64 it's a little weird since 64-bit mode actually defaults to 32-bit data sizes and uses mostly the same opcodes as 32-bit mode, with a prefix byte needed to override this to 64 bits. Addresses default to 64 bits, however. The 32-bit environment is "nice" in that pointers and integers are the same size; not true for most 64-bit in general (http://en.wikipedia.org/wiki/64-bit_computing#64-bit_data_mo... )

But still, trying to fit the x64 version in 64 lines is probably going to be the harder problem. ;-)