MicroPython feature matrix

Settings come from src/freedos_micro_python/port/mpconfigport.h. The port runs at MICROPY_CONFIG_ROM_LEVEL = EXTRA_FEATURES, the richest preset upstream ships.

Enabled

The EXTRA_FEATURES preset itself turns on the language-surface knobs listed first; everything below it is an explicit override on top.

Language surface (from EXTRA_FEATURES)
  compile() / eval() / exec()           input()
  memoryview                            frozenset
  f-strings                             collections.deque + iter/subscr
  __add__ / __radd__ / __iadd__ etc.    function attribute access
  delattr() / setattr()                 math.pi / e / tau / inf / nan
  math.factorial / math.isclose         bytes.hex / fromhex
  str.center / partition / splitlines   bytearray slice-assign
  Emacs REPL keys + auto-indent         Ctrl-C → KeyboardInterrupt

Runtime
  ENABLE_COMPILER         ENABLE_GC               HELPER_REPL
  ENABLE_EXTERNAL_IMPORT  STACK_CHECK             NLR_SETJMP
  MODULE___FILE__         PY_BUILTINS_HELP        PY_BUILTINS_RANGE_BINOP
  USE_INTERNAL_ERRNO      STREAMS_POSIX_API

Numerics
  FLOAT_IMPL  = DOUBLE          (full x87 double-precision)
  FLOAT_FORMAT_IMPL = EXACT     (round-trip shortest decimal)
  LONGINT_IMPL = LONGLONG       (heap-allocated big ints)
  PY_MATH_SPECIAL_FUNCTIONS     (erf, gamma, ...)
  PY_MATH_{ATAN2,FMOD,MODF,POW,GAMMA}_FIX  (CPython-matching edges)

Standard library (extmod)
  io          open(), IOBase, BytesIO, StringIO
  sys         modules / exit / path / argv / exc_info / tracebacklimit
  time        time / time_ns / sleep_ms / ticks_ms / localtime / gmtime / mktime
  random      EXTRA_FUNCS, seeded from BIOS tick counter
  hashlib     SHA-256 + SHA-1 + MD5 (real axtls implementations)
  binascii    full surface incl. CRC32
  deflate     uzlib decoder + DEFLATE_COMPRESS encoder
  re          + sub, match groups, span/start/end
  heapq, json, struct, uctypes, select, _asyncio
  machine     mem8/mem16/mem32 (direct linear-address poke in PMODE/W)

Networking + crypto (the harder lift)
  socket      BSD-style via lwIP (TCP/UDP/DNS, IPv4)
  ssl         axtls (handshake + CERT_REQUIRED with --ca-certs)
  _ssh        libssh2 1.11.1 over axtls + TweetNaCl
              Session.userauth_password / exec / sftp() /
              scp_recv / scp_send / close
  uc386_net   NE2000 packet driver, eth_init / eth_status / eth_set_static
  lwip        lwIP raw module (RX poll, callbacks)
  pktdrv      DOS packet-driver INT 60h harness
  dosint21    raw INT 21h access for DOS-native syscalls

Not implemented

_thread / PY_THREAD               DOS is single-threaded; emulating
                                  pre-emptive threads would mislead.
                                  Cooperative asyncio runs fine.

cmath / PY_CMATH                  Complex numbers — not on the path
                                  for any user we serve today.

weakref / PY_WEAKREF              Off at CORE; default at EXTRA.
                                  Skipped: no concrete use yet.

VFS / PY_VFS                      MICROPY_VFS abstraction (mount,
                                  multiple FS backends) — we have a
                                  flat-file import path through INT
                                  21h instead. Adding VFS would buy
                                  FAT/Lit/Posix mounts and overlay
                                  semantics; not a current need.

network module                    extmod/modnetwork.c (the Network
                                  ABC + cyw43/wiznet/... drivers).
                                  DOS NICs are managed via the
                                  packet-driver interface instead;
                                  uc386_net + lwip cover the same
                                  ground at a lower level.

machine.Pin / I2C / SPI / UART    No DOS-level device model. ISA bus
/Timer/ADC/DAC/PWM/WDT            access works via machine.mem32, but
                                  the typed peripherals would each
                                  need a driver. Not on the path.

bluetooth / espnow / btree        Hardware/RTOS-specific upstream
                                  modules. No DOS analogue exists.

PERSISTENT_CODE_LOAD / .mpy       We don't run mpy-tool, so the
FROZEN_MPY                        frozen-module symbols would be
                                  undefined externs at link time.
                                  Pure-source .py imports work.

In progress

SSH publickey auth                Today only userauth_password is
                                  wired up. session.userauth_publickey
                                  needs real RSA / DH / Ed25519
                                  key-parse in port/libssh2_axtls.c
                                  (currently stubs returning -1).
                                  Tracked in docs/WIP.md.

Frozen-bytecode loading           Wiring mpy-tool.py + the
                                  mp_frozen_* symbols into the
                                  build would let us ship the
                                  asyncio Python files baked into
                                  the .exe. Mechanical, not
                                  research.

Wider lwIP surface                IPv6 is off; UDP multicast and
                                  raw sockets are exposed at the
                                  lwIP layer but not surfaced
                                  through PY_SOCKET. Add as
                                  demand appears.

TCP_NODELAY                       modlwip's setsockopt(TCP_NODELAY)
                                  matches lwIP's TF_NODELAY=0x40
                                  constant, not POSIX TCP_NODELAY=1.
                                  Trivial to fix — open while we
                                  decide whether to break the
                                  lwIP-native users.