py: Overhaul and simplify printf/pfenv mechanism.

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.

1 files changed, 3 insertions, 0 deletions

diff --git a/py/runtime.h b/py/runtime.h
index f05a7d0a8..d171f1582 100644
--- a/py/runtime.h
+++ b/py/runtime.h
@@ -63,6 +63,9 @@ extern const qstr mp_binary_op_method_name[];
 void mp_init(void);
 void mp_deinit(void);
 
+// extra printing method specifically for mp_obj_t's which are integral type
+int mp_print_mp_int(const mp_print_t *print, mp_obj_t x, int base, int base_char, int flags, char fill, int width, int prec);
+
 void mp_arg_check_num(mp_uint_t n_args, mp_uint_t n_kw, mp_uint_t n_args_min, mp_uint_t n_args_max, bool takes_kw);
 void mp_arg_parse_all(mp_uint_t n_pos, const mp_obj_t *pos, mp_map_t *kws, mp_uint_t n_allowed, const mp_arg_t *allowed, mp_arg_val_t *out_vals);
 void mp_arg_parse_all_kw_array(mp_uint_t n_pos, mp_uint_t n_kw, const mp_obj_t *args, mp_uint_t n_allowed, const mp_arg_t *allowed, mp_arg_val_t *out_vals);