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.
diff --git a/py/mpconfig.h b/py/mpconfig.h
index 21ae0c3..c78221f 100644
--- a/py/mpconfig.h
+++ b/py/mpconfig.h
@@ -691,7 +691,7 @@
#define MICROPY_MAKE_POINTER_CALLABLE(p) (p)
#endif
-// If these MP_PLAT_* macros are overridden then the memory allocated by them
+// If these MP_PLAT_*_EXEC macros are overridden then the memory allocated by them
// must be somehow reachable for marking by the GC, since the native code
// generators store pointers to GC managed memory in the code.
#ifndef MP_PLAT_ALLOC_EXEC
@@ -702,6 +702,11 @@
#define MP_PLAT_FREE_EXEC(ptr, size) m_del(byte, ptr, size)
#endif
+// This macro is used to do all output (except when MICROPY_PY_IO is defined)
+#ifndef MP_PLAT_PRINT_STRN
+#define MP_PLAT_PRINT_STRN(str, len) printf("%.*s", (int)len, str)
+#endif
+
#ifndef MP_SSIZE_MAX
#define MP_SSIZE_MAX SSIZE_MAX
#endif