Seedable and reproducible pseudo-random number generator. Implemented
functions are getrandbits(n) (n <= 32) and seed().
The algorithm used is Yasmarang by Ilya Levin:
http://www.literatecode.com/yasmarang
The first argument to the type.make_new method is naturally a uPy type,
and all uses of this argument cast it directly to a pointer to a type
structure. So it makes sense to just have it a pointer to a type from
the very beginning (and a const pointer at that). This patch makes
such a change, and removes all unnecessary casting to/from mp_obj_t.
This patch changes the type signature of .make_new and .call object method
slots to use size_t for n_args and n_kw (was mp_uint_t. Makes code more
efficient when mp_uint_t is larger than a machine word. Doesn't affect
ports when size_t and mp_uint_t have the same size.
POSIX doesn't guarantee something like that to work, but it works on any
system with careful signal implementation. Roughly, the requirement is
that signal handler is executed in the context of the process, its main
thread, etc. This is true for Linux. Also tested to work without issues
on MacOSX.
This basically introduces the MICROPY_MACHINE_MEM_GET_READ_ADDR
and MICROPY_MACHINE_MEM_GET_WRITE_ADDR macros. If one of them is
not defined, then a default identity function is provided.
To let unix port implement "machine" functionality on Python level, and
keep consistent naming in other ports (baremetal ports will use magic
module "symlinking" to still load it on "import machine").
Fixes#1701.
This solves long-standing non-deterministic bug, which manifested itself
on x86 32-bit (at least of reported cases) - segfault on Ctrl+C (i.e.
SIGINT).
ilistdir() returns iterator which yields triples of (name, type, ino)
where ino is inode number for entry's data, type of entry (file/dir/etc.),
and name of file/dir. listdir() can be easily implemented in terms of this
iterator (which is otherwise more efficient in terms of memory use and may
save expensive call to stat() for each returned entry).
CPython has os.scandir() which also returns an iterator, but it yields
more complex objects of DirEntry type. scandir() can also be easily
implemented in terms of ilistdir().
After an I/O event is triggered for fd, event flags are automatically reset,
so no further events are reported until new event flags are set. This is
an optimization for uasyncio, required to account for coroutine semantics:
each coroutine issues explicit read/write async call, and once that trigger,
no events should be reported to coroutine, unless it again explicitly
requests it. One-shot mode saves one linear scan over the poll array.
Per CPython docs, "Registering a file descriptor that’s already registered
is not an error, and has the same effect as registering the descriptor
exactly once."
https://docs.python.org/3/library/select.html#select.poll.register
That's somewhat ambiguous, what's implemented here is that if fd si not
yet registered, it is registered. Otherwise, the effect is equivalent to
modify() method.
Usually this checking is done by VM on jump instructions, but for linear
sequences of instructions and builtin functions this won't happen. Particular
target of this change is long-running builtin functions like time.sleep().
As set by signal handler. This assumes that exception will be raised
somewhere else, which so far doesn't happen for single function call.
Still, it makes sense to handle that in some common place.
This allows the mp_obj_t type to be configured to something other than a
pointer-sized primitive type.
This patch also includes additional changes to allow the code to compile
when sizeof(mp_uint_t) != sizeof(void*), such as using size_t instead of
mp_uint_t, and various casts.
