On , Darryl Gregorash wrote to Scott McNay :
DG> Replying to a message of Scott McNay to Peter Magnusson:
DG>  SM> You might take a look at the AAM and AAD instruction.  As
DG>  SM> you probably know, it's officially a two-byte opcode, but
DG>  SM> it's actually a one-byte opcode followed by a single data
DG>  SM> byte, 0x0A.  If, for example, you use 0x08 instead, you get
DG>  SM> an instruction that converts binary to/from octal.
DG>  SM> Apparently, on the NEC chips (I dont have a PC or XT
DG>  SM> motherboard to test with anymore, and I doubt that I still
DG>  SM> have any NEC chips either, so I can't confirm this),
DG>  SM> supposedly the AAM and AAD instructions don't work
DG>  SM> correctly for any operand other than 0x0A.  Thus, a good
DG>  SM> reason to not rely upon such ondocumented behavior.
DG> I had a V20; they work fine for any byte following the opcode, because 
DG> they ignore that byte.. decimal values only.
That's been my experience with it. The only use I ever had for
using a data byte other than 0A was to unpack the values into
nibbles for dual BCD displays.
Glen...
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