Sometimes there's a bunch of junk in the binary that isn't used for
anything. Often it's there to make things line up at the start of
a page boundary.
This adds a ".junk" directive that tells the disassembler that it
can safely disregard the contents of a region. If the region ends
on a power-of-two boundary, an alignment value can be specified.
The assembly source generators will output an alignment directive
when possible, a .fill directive when appropriate, and a .dense
directive when all else fails. Because we're required to regenerate
the original data file, it's not always possible to avoid generating
a hex dump.
This worked, sort of. The problem is that SourceGen will revert to
hex output in certain situations, such as a broken symbolic
reference. There happens to be one in the ZIPPY example, and it's
on a relative branch.
The goal with the segment stuff is to allow cc65 to treat the
source as relocatable code. In that context, a relative branch to
an absolute address doesn't make any sense, so the assembler reports
a range error.
We don't currently have a mechanism that guarantees no references
are broken (and no affordance for finding them), so we can't make
this mode the default yet.
Instead, we continue to use the generic config, but generate the
correct set of lines as comments.
(issue #39)
