Stack is full descending and must be 8-byte aligned. It must start off
pointing to just above the last byte of RAM.
Previously, stack started pointed to last byte of RAM (eg 0x2001ffff)
and so was not 8-byte aligned. This caused a bug in combination with
alloca.
This patch also updates some debug printing code.
Addresses issue #872 (among many other undiscovered issues).
This allows to set the pulse width (for PWM mode) as a ratio relative to
the period of the timer. Eg, 0.5 is a 50% duty cycle. You can set the
ratio in the channel init, or using channel.pulse_width_ratio; the
latter can also read the pulse width as a ratio.
Heap RAM was being allocated to print dicts and do some other types of
iterating. Now these iterations use 1 word of state on the stack.
Deleting elements from a dict was not allowing the value to be reclaimed
by the GC. This is now fixed.
By measuring SD card addresses in blocks and not bytes, one can get away
with using 32-bit numbers.
This patch also uses proper atomic lock/unlock around SD card
read/write, adds SD.info() function, and gives error code for failed
read/writes.
sys.exit always raises SystemExit so doesn't need a special
implementation for each port. If C exit() is really needed, use the
standard os._exit function.
Also initialise mp_sys_path and mp_sys_argv in teensy port.
Eventually, viper wants to be able to use raw pointers to strings and
arrays for efficient access. But for now, let's just load strings as a
Python object so they can be used as normal. This will anyway be
compatible with eventual intended viper behaviour.
Addresses issue #857.
Damien George
Dave Hylands
Felix Domke