The targets allow to run cc65 programs in the sim65 exection
einvironment. As there are no "real" i/o facilities there's no
need for header files. Paravirtualized entry points are mapped
to $FFF0 ff. There's a large cc65 progam area from $0200-$FFEF.
The binary format includes a one-byte header indicating the required
execution environment: The value 0 means 6502 and the value 1
means 65C02. The load adress for the binary is fixed to $0200.
Note: Running sim65C02 programs currently doesn't work bcause
sim65 doesn't actually implement 65C02 opcodes.
The sim65 source code has been a construction site for over a decade.
I was looking for a simple cc65 program execution environment for
regression tests. So I decided to re-purpose sim65 for that task by
removing about everything but the 6502 emulation.
There's no memory mapped i/o emulation whatsoever. Rather exit(),
open(), close(), read() and write() calls are supported by mapping
them through a thin paravirtualization layer to the corresponding
host os functions.
Note: The sim65 6502 emulation provides means to switch between
6502 and 65C02 emulation but currently there are no actual 65C02
opcodes implemented.
There are two reasons for removing this dependency:
- If someone does 'make avail' on the top level Makefile he ends up with
binaries but without libraries - not nice. Better do just "nothing" and
have hin understand that he needs to do 'make [all]' on the top level
Makfile first.
- If 'make avail' is done via 'sudo' it isn't desirable to do a large amount
of work as root.
BTW: I wasn't sure if this dependency is a good thing in the first place
but I saw it in many examples ('install' depending on 'all') so I did it too.
The [un]install make goals have a rather fixed meaning for *ix users. The simple
symlinks provided here don't match the expectations users have from [un]install.
Therefore it is appropriate to rename them to "something" not tied to specific
expectations.
While ca65, cc65 and ld65 have built-in paths cl65 doesn't.
That means that up to now cl65 depended on the binaries
being found in the path env var. However it makes sense
to presume that the binaries are located in the very same
directory cl65 is located in. So whatever pathname was
suitable to run cl65 should be suitable to run the other
binaries too. But if for some reason there's no valid
argv[0] or if it doesn't contain at least one directory
delimiter ('/' or '\') then fall back to relying on the
path env var.
In contrast to *IX it doesn't make much sense to add compile time defined
search paths to Windows binaries: There's no standard path like /usr/local/bin
(and there are no symbolic links to link from there to another location).
On the other hand it's (again in contrast to *IX) easy for Windows binaries
to determine their own paths. Therefore it's appropriate to make use of that
to add run time defined default search paths.
Maybe I'm naive but even after thinking about it for quite
some time I can't see why it should hurt to just build the
cc65 binaries from the sources "in place" and have 'make
install' simply create some symlinks in usr/local/bin.
The new Makfile builds the binaries with builtin search paths
matching their build location. So the symlinks in usr/local/bin
allow to allow to use them out-of-the-box without additional
environment variables.
