libs/libc/stdio: This commits makes the nano-printf the defualt logic for the printf family. The legacy printf is still available via CONFIG_LIBC_PRINT_LEGACY. This commit also modifies the nano-prinf configure: The PRINT_LEVEL is not long selectable. Instead, a not CONFIG_LIBC_PRINT_MINIMAL boolean setting was added and the PRINT_LEVEL is derived from a combination of CONFIG_LIBC_PRINT_MINIMAL, CONFIG_LIBC_FLOATINGPOINT, and CONFIG_LIBC_LONG_LONG.

libs/libc/stdio/Kconfig

@@ -48,7 +48,17 @@ config NUNGET_CHARS
 	int "Number unget() characters"
 	default 2
 	---help---
-		Number of characters that can be buffered by ungetc() (Only if NFILE_STREAMS > 0)
+		Number of characters that can be buffered by ungetc() (Only if
+		NFILE_STREAMS > 0)
+
+config LIBC_PRINT_LEGACY
+	bool "Enable legacy printf logic"
+	default n
+	---help---
+		By default, printf (and friends) are implemented using a port from
+		newlib-nano.  That port can be signifcantly smaller, especially if
+		floating support is enabled.  This option may is avaiable, however,
+		to revert to the legacy printf version is so desired.
 
 config LIBC_FLOATINGPOINT
 	bool "Enable floating point in printf"
@@ -57,12 +67,6 @@ config LIBC_FLOATINGPOINT
 		By default, floating point support in printf, sscanf, etc. is
 		disabled.  This option will enable floating point support.
 
-		if CONFIG_NANO_PRINTF is enabled, tnen this option works a
-		little differently.  You still have to select
-		CONFIG_NANO_PRINTLEVEL=3 to get floating point support.  In
-		case, this option extends the range of acceptable
-		values that will permit selection of CONFIG_NANO_PRINTLEVEL=3.
-
 config LIBC_LONG_LONG
 	bool "Enable long long support in printf"
 	default y if !DEFAULT_SMALL
@@ -76,6 +80,20 @@ config LIBC_LONG_LONG
 		libraries that will be drawn into the build if long long support
 		is enabled.
 
+config LIBC_PRINT_MINIMAL
+	bool "Minimal formatting support in printf"
+	default y if DEFAULT_SMALL
+	default n if !DEFAULT_SMALL
+	depends on !LIBC_FLOATINGPOINT && !LIBC_LONG_LONG && !LIBC_PRINT_LEGACY
+	---help---
+		Enables support for long long formats in printf, sscanf, etc. is
+		enabled.  This is enabled by default but if you are trying to
+		reduce the FLASH footprint, then disabling this feature is one
+		option.  The FLASH saves comes not from disabling the long long
+		formats, but rather from omitting the large long long arithmetic
+		libraries that will be drawn into the build if long long support
+		is enabled.
+
 config LIBC_SCANSET
 	bool "Scanset support"
 	default n
@@ -114,29 +132,4 @@ config MEMCPY_VIK
 		Select this option for improved performance at the expense of increased
 		size. See licensing information in the top-level COPYING file.
 
-config NANO_PRINTF
-	bool "Use nano printf code"
-	default y if DEFAULT_SMALL
-	default n if !DEFAULT_SMALL
-	---help---
-		Replace printf code with version from newlib-nano. Can be
-		signifcantly smaller, especially if floating support is enabled.
-		However, it does not include 'long long' support.
-
-config NANO_PRINTLEVEL
-	int "Nano printf support level"
-	default 2 if !LIBC_FLOATINGPOINT
-	default 3 if LIBC_FLOATINGPOINT
-	range 1 2 if !LIBC_FLOATINGPOINT && !LIBC_LONG_LONG
-	range 1 3 if LIBC_FLOATINGPOINT && !LIBC_LONG_LONG
-	range 2 2 if !LIBC_FLOATINGPOINT && LIBC_LONG_LONG
-	range 2 3 if LIBC_FLOATINGPOINT && LIBC_LONG_LONG
-	depends on NANO_PRINTF
-	---help---
-		Nano printf can be built into more than one support level.  The
-		default is to offer the usual modifiers and integer formatting
-		support (level 2).  Level 1 maintains a minimal version that just
-		offers integer formatting, but no modifier support whatsoever.
-		Level 3 is intented for floating point support.
-
 endmenu #Standard C I/O

libs/libc/stdio/Make.defs

@@ -45,24 +45,20 @@ CSRCS += lib_zeroinstream.c lib_nullinstream.c lib_nulloutstream.c
 CSRCS += lib_sscanf.c lib_vsscanf.c lib_libvscanf.c lib_libnoflush.c
 CSRCS += lib_libsnoflush.c
 
-ifeq ($(CONFIG_NANO_PRINTF),y)
+ifeq ($(CONFIG_LIBC_PRINT_LEGACY),y)
-
-CSRCS += nano_libvsprintf.c nano_ultoa_invert.c
-
-ifeq ($(CONFIG_NANO_PRINTLEVEL),3)
-
-CSRCS += nano_dtoa_engine.c nano_dtoa_data.c
-
-endif
-
-else
 
 CSRCS += lib_libvsprintf.c
-
 ifeq ($(CONFIG_LIBC_FLOATINGPOINT),y)
 CSRCS += lib_dtoa.c
 endif
 
+#else
+
+CSRCS += nano_libvsprintf.c nano_ultoa_invert.c
+ifeq ($(CONFIG_LIBC_FLOATINGPOINT),y)
+CSRCS += nano_dtoa_engine.c nano_dtoa_data.c
+endif
+
 endif
 
 # The remaining sources files depend upon C streams

libs/libc/stdio/nano_libvsprintf.c

@@ -66,24 +66,15 @@
  * is to offer the usual modifiers and integer formatting support
  * (level 2).  Level 1 maintains a minimal version that just offers
  * integer formatting, but no modifier support whatsoever.  Level 3 is
- * intented for floating point support.
+ * intended for floating point support.
  */
 
-#if defined(CONFIG_NANO_PRINTLEVEL)
+#if defined(CONFIG_LIBC_FLOATINGPOINT)
-#  define PRINTF_LEVEL CONFIG_NANO_PRINTLEVEL
-#elif defined(CONFIG_LIBC_FLOATINGPOINT)
 #  define PRINTF_LEVEL PRINTF_FLT
+#elif defined(CONFIG_LIB_LONG_LONG) || !defined(CONFIG_LIBC_PRINT_MINIMAL)
+#  define PRINT_LEVEL PRINTF_STD
 #else
-#  define PRINTF_LEVEL PRINTF_STD
+#  define PRINT_LEVEL PRINTF_MIN
-#endif
-
-#if PRINTF_LEVEL == PRINTF_MIN || PRINTF_LEVEL == PRINTF_STD || \
-    PRINTF_LEVEL == PRINTF_FLT
-
-/* OK */
-
-#else
-#  error "Not a known printf level."
 #endif
 
 #ifdef putc