Sometimes you can simply change the line to something like this
newmem:
mov [rbx],(double)100 // or if its float you can write (float) if its an integer you can simply do # without the parenthesis
everything else can remain the same. most of the time it works but some games have checks later in the assembly which can make weird results or crashes. just depends on what you are trying to do.
will result in invalid code as the value in `mov [memoryaddress],value` can only be 32-bits
You would think whichever moron made the AMD64 op codes for a 64-bit environment would allow for the transfer of 64-bit data, but I guess that makes too much fucking sense.