The cc65 tool chain comes with V.24 drivers so it seems reasonable to use the existing Contiki SLIP driver to implement network access via SLIP as alternative to Ethernet.
Some notes:
- The Ethernet configuration was simplified in order to allow share it with SLIP.
- The Contiki SLIP driver presumes an interrupt driven serial receiver to write into the SLIP buffer. However the cc65 V.24 drivers aren't up to that. Therefore the main loops were extended to pull received data from the V.24 buffers and push it into the SLIP buffer.
- As far as I understand the serial sender is supposed to block until the data is sent. Therefore a loop calls the non-blocking V.24 driver until the data is sent.
On all platforms there's only one V.24 driver available. Therefore V.24 drivers are always loaded statically.
On the Apple][ the mouse driver is now loaded statically - independently from SLIP vs. Ethernet. After all there's only one mouse driver available. However there's a major benefit with SLIP: Here all drivers are loaded statically. Therefore the dynamic module loader isn't necessary at all. And without the loader the heap manager isn't necessary at all. This allows for a reduction in code size roughly compensating for the size of the SLIP buffer.
After all there's no momentum for a W5100-based Ethernet solution on the ATARI. So I revert to static linkage of the CS8900A driver as this improves program load times.
CC_FASTCALL was introduced many years ago for the cc65 tool chain. It was never used for another tool chain. With a798b1d648 the cc65 tool chain doesn't need CC_FASTCALL anymore.
Made Ethernet drivers easier to consume by assembly programs.
* Replaced function pointers with JMP instructions.
* Provide return values additionally via Carry flag.
Reset Ethernet chips on initialization.
Both for the CS8900A and the W5100 the data sheets just say that
the RESET bit is automatically cleared after the RESET. This may
be interpreted in two ways:
1) There's no need to be afraid of reading the RESET bit as 1 and
unintentionally trigger a RESET by writing it back after ORing in
some other bit.
2) The RESET process isn't complete before the RESET bit hasn't
become 0 again.
It's impossible for me to empirically falsify the latter option
as the drivers are supposed to work on faster machines than the
ones I have access to. And if the RESET process includes things
like oscillators then the time to complete the RESET could differ
even between multiple exemplars of the same chip. Therefore I
opted to presume the latter option.
However that means a non-exsistent chip may cause an infinite
loop while waiting for the RESET bit to be cleared so I finally
added code to detect the presence of the Ethernet chips. There's
a risk of a chip being locked up in a way that makes the detection
fail - and therefore the RESET not being performed. This catch-22
needs to be solved by the user doing a hard RESET.
