You are only going to see a subset of your bits anyhow. Assuming you are shifting out at 9600 baud, then each character takesa about 1000usec to print anyhow.

If you're using BASIC 52, the print routine is not interrupt driven if I remember, so the code is sitting doing nothing until the character is shifted out anyway.

To do assembler code with a '52 isn't too hard. If you know anything about it, you have a vector table at 2000H, and code like
10 CALL 1
REM calls location 2000H+2*N
REM where N is the argument of the call REM (1 in this case)
REM there yo place a JMP to your code.
REM your variables can be pushed onto the stacks, but this is too tricky to deal with in the forum