The documentation for 64tass says you're required to pass "--ascii"
when the source file is ASCII (as opposed to PETSCII). We were
ignoring this, but it turns out that everything works a bit better
if we don't.
So we now pass "--ascii" on the command line, and add a two-line
character encoding definition to every file that is generated with
ASCII as the default encoding. The sg_petscii and sg_screen
encodings go away, as PETSCII is now the default, and we can use the
built-in "screen" encoding.
During a discussion with the cc65 developers, I became convinced that
generating "MVN $01,$02" is wrong, and "MVN #$01,#$02" is correct.
64tass, cc65, and Merlin 32 all accept this syntax; only ACME does
not. Operands without a leading '#' should be treated as 24-bit
values, and have the bank byte extracted.
This change updates the on-screen display and assembled output to
include the '#'. The ACME generator uses a Quirk to suppress the
hash mark. (It doesn't currently accept values larger than 8 bits,
so there's no ambiguity.)
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)
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)
