From 7d9cde1031040a4931d6e12da7d9767b7e1d85d4 Mon Sep 17 00:00:00 2001 From: Stefan Roese Date: Mon, 23 Nov 2015 07:00:22 +0100 Subject: lib/tiny-printf.c: Add tiny printf function for space limited environments 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 Cc: Simon Glass Cc: Hans de Goede Cc: Tom Rini Cc: Albert Aribaud --- lib/tiny-printf.c | 130 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 130 insertions(+) create mode 100644 lib/tiny-printf.c (limited to 'lib/tiny-printf.c') diff --git a/lib/tiny-printf.c b/lib/tiny-printf.c new file mode 100644 index 0000000000..d743a364e9 --- /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 +#include +#include + +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; +} -- cgit v1.2.1