The mouse reference is a pointer. If it's NULL, the driver uses a default. If it's non-NULL, then it points to a function that the driver can call. That function will adjust the driver's calibration value. It could ask the user to adjust the pen; or, it could read a file that holds a value from a previous calibration.
Application writers can choose how it's done: a function that's provided by the library, a custom function, or nothing.
If the variable 'prefix' is defined then the builtin search paths are set to
$(prefix)/lib/cc65/... allowing to build binaries intended for installation.
Note that the library build still works with these binaries as it generally
overrides the builtin search paths by setting the CC65_HOME env var.
Originally I used the usual variables (like $(CC) and $(CFLAGS) ) but after
all this doesn't make sense as any predefined values and/or user defined
settings can only be wrong.
Occasionally dynamically drivers suffer from not being to refer to
content in the C library. Therefore I added a mechanism to allow
a C library for a certian target to define a symbol that will be
handed over to dynamic drivers for that target. Then the drivers
can use their refernce to that symbol to access content in the C
library.
The libraries build is prepared to work with binaries not part of the current
working tree. But in this case the default search path surely points to some
other working tree. Even the binaries in this working tree might have been
compiled with non-standard builtin search paths.
Anyway when building the libraries we want always to use the headers from
the current working tree. Therefore we want to set them explicitly. Instead
of setting all in all five paths on the command lines of ca65, cc65 and ld65 I
opted to just set the single environment variable.
They use the mouse driver programming interface.
Added a test program for lightpen drivers. Now, it knows about only those two drivers; it will need updating when others are added.
The mouse driver source code in question was removed two years
ago with commit 6cbbe66c87.
It seems however desirable to have it around visible in the source
code tree for reference purposes.
The target 'atarixl' is to be used for Atari XL (and better) machines.
It will disable the OS ROM and enable the Shadow RAM available on
those machine.
Note: This commit is only the inital step towards for this goal that just
replicates the target 'atari' as a starting point!
As a preparation for the introduction of the 'atarixl' target it is
necessary that all drivers have a base name...
- no longer than 7 characters
- with a common prefix
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.
