To avoid confusing the assembler, expressions with a leading
parenthesis like "(foo & $ffff) + 1" are prefixed with a "0+". This
is not necessary if the operand begins with a '#'.
(issue #16)
This adds a null check on the dfd argument in FormatDataOp() to see
if we can prevent a crash. The opcode/operand are presented as
"!FAILED!" to make it obvious to the user that something has gone
wrong. Hopefully this will allow capture of a project that exhibits
the problem.
We now insert parenthesis as needed. This can cause problems in
some situations, so we always prefix parenthetical expressions with
"0+", which looks goofy and is unnecessary for immediate operands.
But it does generate working source code.
Renamed the "simple" expression mode to "common", as it's not
particularly simple but is what you'd expect most assemblers to do.
(OTOH, life has been full of surprises.)
(issue #16)
Gave cc65 its own expression generator, as the precedence table seems
atypical if not unique. Configured 64tass to use the "simple"
expression mode.
Added some operations on a 32-bit constant to 2007-labels-and-symbols
to exercise the current worst-case expression (shift + AND + add).
Tweaked the Merlin expression generator to handle it.
(issue #16)
