@ Shift a single 1 in the MSb into all ones
SSTTSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSN | PUSH -(2^63)
SSSTTTTTTN | PUSH +63
NSTTSTTSSN | JSR > 101100 (rshift)
@ Shift a single 1 in the MSb into all ones
SSTTSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSN | PUSH -(2^63)
SSSTTTTTTN | PUSH +63
NSTTSTTSSN | JSR > 101100 (rshift)