LOOPW label       16-Bit 80386 LOOPW (TASM Only)     Flags: O D I T S Z A P C

     Normally, whether or not ECX is used as the loop index is determined by
     whether the instruction is in a 16- or 32-bit segment. However, TASM lets
     you indicate that you want to use the CX (not ECX) register for LOOP
     regardless of the current segment with the LOOPW instruction.

     See LOOP for more information.