The following AREUH bug has been reported by Fred Vanderwindt:

The mnemonic D1=AS is assembled as 138 hex - which is D0=AS. D1=AS should be
assembled as 139 hex. Replace any D1=AS instructions with NIBHEX 139.

NOTE: The HP-71 Forth/Assembler ROM has the same bug. In addition, the Forth/
Assembler ROM also gives a bad class to B=B+B A. This mnemonics should therefore
be replaced with NIBHEX C5 in order to insure compatibility. Forth/Assembler ROM
users also must start assembly from the DECIMAL mode if the lex to be assembled
has 10 or more keywords. See John Baker's FIX5F for further details.