This removes mpz_as_int, since that was a terrible function (it
implemented saturating conversion).
Use mpz_as_int_checked and mpz_as_uint_checked. These now work
correctly (they previously had wrong overflow checking, eg
print(chr(10000000000000)) on 32-bit machine would incorrectly convert
this large number to a small int).
For accel to start-up reliably, need to wait 30ms between on/off, and
30ms for it to enter active mode. With this fix the accel can be read
immediately after initialising it.
Addresses issue #763.
Before, pyb.stdin/pyb.stdout allowed some kind of access to the USB VCP
device, but it was basic access.
This patch adds a proper USB_VCP class and object with much more control
over the USB VCP device. Create an object with pyb.USB_VCP(), then use
this object as if it were a UART object. It has send, recv, read,
write, and other methods. send and recv allow a timeout to be specified.
Addresses issue 774.
Many OSes/CPUs have affinity to put "user" data into lower half of address
space. Take advantage of that and remap such addresses into full small int
range (including negative part).
If address is from upper half, long int will be used. Previously, small
int was returned for lower quarter of address space, and upper quarter. For
2 middle quarters, long int was used, which is clearly worse schedule than
the above.
The user code should call micropython.alloc_emergency_exception_buf(size)
where size is the size of the buffer used to print the argument
passed to the exception.
With the test code from #732, and a call to
micropython.alloc_emergenncy_exception_buf(100) the following error is
now printed:
```python
>>> import heartbeat_irq
Uncaught exception in Timer(4) interrupt handler
Traceback (most recent call last):
File "0://heartbeat_irq.py", line 14, in heartbeat_cb
NameError: name 'led' is not defined
```