• Damien George's avatar
    py: Overhaul and simplify printf/pfenv mechanism. · 7f9d1d6a
    Damien George authored
    Previous to this patch the printing mechanism was a bit of a tangled
    mess.  This patch attempts to consolidate printing into one interface.
    All (non-debug) printing now uses the mp_print* family of functions,
    mainly mp_printf.  All these functions take an mp_print_t structure as
    their first argument, and this structure defines the printing backend
    through the "print_strn" function of said structure.
    Printing from the uPy core can reach the platform-defined print code via
    two paths: either through mp_sys_stdout_obj (defined pert port) in
    conjunction with mp_stream_write; or through the mp_plat_print structure
    which uses the MP_PLAT_PRINT_STRN macro to define how string are printed
    on the platform.  The former is only used when MICROPY_PY_IO is defined.
    With this new scheme printing is generally more efficient (less layers
    to go through, less arguments to pass), and, given an mp_print_t*
    structure, one can call mp_print_str for efficiency instead of
    mp_printf("%s", ...).  Code size is also reduced by around 200 bytes on
    Thumb2 archs.