[U-Boot] [PATCH 3/4 v2] lib/tiny-printf.c: Add tiny printf function for space limited environments
Stefan Roese
sr at denx.de
Mon Nov 16 15:26:33 CET 2015
This patch adds a small printf() version that supports all basic formats.
Its intented to be used in U-Boot SPL versions on platforms with very
limited internal RAM sizes.
To enable it, just define CONFIG_USE_TINY_PRINTF in your defconfig. This
will result in the SPL using this tiny function and the main U-Boot
still using the full-blown printf() function.
This code was copied from:
http://www.sparetimelabs.com/printfrevisited
With mostly only coding style related changes so that its checkpatch
clean.
The size reduction is about 2.5KiB. Here a comparison for the db-mv784mp-gp
(Marvell AXP) SPL:
Without this patch:
58963 18536 1928 79427 13643 ./spl/u-boot-spl
With this patch:
56542 18536 1956 77034 12cea ./spl/u-boot-spl
Note:
To make it possible to compile tiny-printf.c instead of vsprintf.c when
CONFIG_USE_TINY_PRINTF is defined, the functions printf() and vprintf() are
moved from common/console.c into vsprintf.c in this patch.
Signed-off-by: Stefan Roese <sr at denx.de>
Cc: Simon Glass <sjg at chromium.org>
Cc: Hans de Goede <hdegoede at redhat.com>
Cc: Tom Rini <trini at konsulko.com>
Cc: Albert Aribaud <albert.u.boot at aribaud.net>
---
v2:
- Patch split-up into multiple patches
- Added comment about supported formats in Kconfig
common/console.c | 36 ---------------
lib/Kconfig | 10 +++++
lib/Makefile | 7 ++-
lib/tiny-printf.c | 130 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
lib/vsprintf.c | 36 +++++++++++++++
5 files changed, 182 insertions(+), 37 deletions(-)
create mode 100644 lib/tiny-printf.c
diff --git a/common/console.c b/common/console.c
index cf86b76..2bfd59f 100644
--- a/common/console.c
+++ b/common/console.c
@@ -535,42 +535,6 @@ void puts(const char *s)
}
}
-int printf(const char *fmt, ...)
-{
- va_list args;
- uint i;
- char printbuffer[CONFIG_SYS_PBSIZE];
-
- va_start(args, fmt);
-
- /*
- * For this to work, printbuffer must be larger than
- * anything we ever want to print.
- */
- i = vscnprintf(printbuffer, sizeof(printbuffer), fmt, args);
- va_end(args);
-
- /* Print the string */
- puts(printbuffer);
- return i;
-}
-
-int vprintf(const char *fmt, va_list args)
-{
- uint i;
- char printbuffer[CONFIG_SYS_PBSIZE];
-
- /*
- * For this to work, printbuffer must be larger than
- * anything we ever want to print.
- */
- i = vscnprintf(printbuffer, sizeof(printbuffer), fmt, args);
-
- /* Print the string */
- puts(printbuffer);
- return i;
-}
-
/* test if ctrl-c was pressed */
static int ctrlc_disabled = 0; /* see disable_ctrl() */
static int ctrlc_was_pressed = 0;
diff --git a/lib/Kconfig b/lib/Kconfig
index 30e84ed..9d580e4 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -36,6 +36,16 @@ config SYS_VSNPRINTF
Thumb-2, about 420 bytes). Enable this option for safety when
using sprintf() with data you do not control.
+config USE_TINY_PRINTF
+ bool "Enable tiny printf() version"
+ help
+ This option enables a tiny, stripped down printf version.
+ This should only be used in space limited environments,
+ like SPL versions with hard memory limits. This version
+ reduces the code size by about 2.5KiB on armv7.
+
+ The supported format specifiers are %c, %s, %u/%d and %x.
+
config REGEX
bool "Enable regular expression support"
default y if NET
diff --git a/lib/Makefile b/lib/Makefile
index 3eecefa..54b6555 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -79,7 +79,12 @@ obj-y += string.o
obj-y += time.o
obj-$(CONFIG_TRACE) += trace.o
obj-$(CONFIG_LIB_UUID) += uuid.o
-obj-y += vsprintf.o
obj-$(CONFIG_LIB_RAND) += rand.o
+ifeq ($(CONFIG_SPL_BUILD)$(CONFIG_USE_TINY_PRINTF),yy)
+obj-y += tiny-printf.o
+else
+obj-y += vsprintf.o
+endif
+
subdir-ccflags-$(CONFIG_CC_OPTIMIZE_LIBS_FOR_SPEED) += -O2
diff --git a/lib/tiny-printf.c b/lib/tiny-printf.c
new file mode 100644
index 0000000..d743a36
--- /dev/null
+++ b/lib/tiny-printf.c
@@ -0,0 +1,130 @@
+/*
+ * Tiny printf version for SPL
+ *
+ * Copied from:
+ * http://www.sparetimelabs.com/printfrevisited/printfrevisited.php
+ *
+ * Copyright (C) 2004,2008 Kustaa Nyholm
+ *
+ * SPDX-License-Identifier: LGPL-2.1+
+ */
+
+#include <common.h>
+#include <stdarg.h>
+#include <serial.h>
+
+static char *bf;
+static char buf[12];
+static unsigned int num;
+static char uc;
+static char zs;
+
+static void out(char c)
+{
+ *bf++ = c;
+}
+
+static void out_dgt(char dgt)
+{
+ out(dgt + (dgt < 10 ? '0' : (uc ? 'A' : 'a') - 10));
+ zs = 1;
+}
+
+static void div_out(unsigned int div)
+{
+ unsigned char dgt = 0;
+
+ num &= 0xffff; /* just for testing the code with 32 bit ints */
+ while (num >= div) {
+ num -= div;
+ dgt++;
+ }
+
+ if (zs || dgt > 0)
+ out_dgt(dgt);
+}
+
+int printf(const char *fmt, ...)
+{
+ va_list va;
+ char ch;
+ char *p;
+
+ va_start(va, fmt);
+
+ while ((ch = *(fmt++))) {
+ if (ch != '%') {
+ putc(ch);
+ } else {
+ char lz = 0;
+ char w = 0;
+
+ ch = *(fmt++);
+ if (ch == '0') {
+ ch = *(fmt++);
+ lz = 1;
+ }
+
+ if (ch >= '0' && ch <= '9') {
+ w = 0;
+ while (ch >= '0' && ch <= '9') {
+ w = (((w << 2) + w) << 1) + ch - '0';
+ ch = *fmt++;
+ }
+ }
+ bf = buf;
+ p = bf;
+ zs = 0;
+
+ switch (ch) {
+ case 0:
+ goto abort;
+ case 'u':
+ case 'd':
+ num = va_arg(va, unsigned int);
+ if (ch == 'd' && (int)num < 0) {
+ num = -(int)num;
+ out('-');
+ }
+ div_out(10000);
+ div_out(1000);
+ div_out(100);
+ div_out(10);
+ out_dgt(num);
+ break;
+ case 'x':
+ case 'X':
+ uc = ch == 'X';
+ num = va_arg(va, unsigned int);
+ div_out(0x1000);
+ div_out(0x100);
+ div_out(0x10);
+ out_dgt(num);
+ break;
+ case 'c':
+ out((char)(va_arg(va, int)));
+ break;
+ case 's':
+ p = va_arg(va, char*);
+ break;
+ case '%':
+ out('%');
+ default:
+ break;
+ }
+
+ *bf = 0;
+ bf = p;
+ while (*bf++ && w > 0)
+ w--;
+ while (w-- > 0)
+ putc(lz ? '0' : ' ');
+ while ((ch = *p++))
+ putc(ch);
+ }
+ }
+
+abort:
+ va_end(va);
+ return 0;
+}
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 4c82837..dd8380b 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -861,6 +861,42 @@ int sprintf(char *buf, const char *fmt, ...)
return i;
}
+int printf(const char *fmt, ...)
+{
+ va_list args;
+ uint i;
+ char printbuffer[CONFIG_SYS_PBSIZE];
+
+ va_start(args, fmt);
+
+ /*
+ * For this to work, printbuffer must be larger than
+ * anything we ever want to print.
+ */
+ i = vscnprintf(printbuffer, sizeof(printbuffer), fmt, args);
+ va_end(args);
+
+ /* Print the string */
+ puts(printbuffer);
+ return i;
+}
+
+int vprintf(const char *fmt, va_list args)
+{
+ uint i;
+ char printbuffer[CONFIG_SYS_PBSIZE];
+
+ /*
+ * For this to work, printbuffer must be larger than
+ * anything we ever want to print.
+ */
+ i = vscnprintf(printbuffer, sizeof(printbuffer), fmt, args);
+
+ /* Print the string */
+ puts(printbuffer);
+ return i;
+}
+
static void panic_finish(void) __attribute__ ((noreturn));
static void panic_finish(void)
--
2.6.3
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