LWASM supports all documented MC6809 instructions as defined by
Motorola. By default, this does not include any MC6800 compatibility
instructions. As of LWASM 4.11, those compatibility instructions can be
enabled using the --6800compat option or the
6800compat pragma. It also supports all known HD6309
instructions. While there is general agreement on the mnemonics for most
of the 6309 instructions, there is some variance with the block transfer
instructions. TFM for all four variations seems to have gained the most
traction and, thus, this is the form that is recommended for LWASM.
However, it also supports COPY, COPY-, IMP, EXP, TFRP, TFRM, TFRS, and TFRR.
It further adds COPY+ as a synomym for COPY, IMPLODE for IMP, and EXPAND for
EXP.
By default, LWASM accepts 6309 instructions. However, using the
--6809 parameter, you can cause it to throw errors on
6309 instructions instead.
The standard addressing mode specifiers are supported. These are the hash sign ("#") for immediate mode, the less than sign ("<") for forced eight bit modes, and the greater than sign (">") for forced sixteen bit modes.
Additionally, LWASM supports using the asterisk ("*") to indicate base page addressing. This should not be used in hand-written source code, however, because it is non-standard and may or may not be present in future versions of LWASM.