Hello Earl,
I think the proper orientation is r3r2r1r0 = 00000100h = 256d.
There is an easy way to troubleshoot these type of problems. Download a program called JSIM.EXE. Install it and you can view the results of the code you are trying to debug. It takes about five minutes to view any change you make. It is public domain software and you can find it by using www.google.com.
When you compile your program (i.e. A51.EXE testprog.asm) copy the testprog.obj to testprog.hex. JSIM.EXE expects to see a hex file in order for you to use it.
Good luck,
Charles Bannister