  ++ A L U   -   A R I T H M E T I C  &   L O G I C A L   U N I T ++

Q contains an ALU to enable macros to execute small general-purpose programs.
The emulated processor is stack-based with 512 integer and 512 real memory
locations, and direct access to Q's 80 tabs. It has integer and floating point
register stacks (R & F) currently 16 deep, an index register (X) and a read-only
results register (Q) (for result codes from the main editor).

Instructions can cause a skip of the next 2 characters in the invoking macro, in
the same way as ^NS does.

Macros 7000 - 7777 implement the (long) integer memory locations and macros
13000 to 13777 implement the (double) reals. These macros may be defined using
N-NEWMACRO or ^NM^<7ooo>, and retrieved using ^ND^N^<7ooo> (use 13 instead of 7
for the reals). When using N-NEWMACRO to define one of these macros, do not code
^NU after the number.

Instructions are pseudomacros, but one should always code them using their
symbolic opcodes, because the relationship between opcode and macro number can
change between revisions of Q.

When coding a symbolic opcode, do *not* code a preceding ^N.
