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/*
* Copyright (c) 2010, 2013-2014 Wind River Systems, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/**
* @file
* @brief Low-level debug output
*
* Low-level debugging output. Platform installs a character output routine at
* init time. If no routine is installed, a nop routine is called.
*/
#include <misc/printk.h>
#include <stdarg.h>
#include <toolchain.h>
#include <sections.h>
static void _printk_dec_ulong(const unsigned long num);
static void _printk_hex_ulong(const unsigned long num);
/**
* @brief Default character output routine that does nothing
* @param c Character to swallow
*
* @return 0
*/
static int _nop_char_out(int c)
{
ARG_UNUSED(c);
/* do nothing */
return 0;
}
int (*_char_out)(int) = _nop_char_out;
/**
* @brief Install the character output routine for printk
*
* To be called by the platform's console driver at init time. Installs a
* routine that outputs one ASCII character at a time.
* @param fn putc routine to install
*
* @return N/A
*/
void __printk_hook_install(int (*fn)(int))
{
_char_out = fn;
}
/**
* @brief Printk internals
*
* See printk() for description.
* @param fmt Format string
* @param ap Variable parameters
*
* @return N/A
*/
static inline void _vprintk(const char *fmt, va_list ap)
{
int might_format = 0; /* 1 if encountered a '%' */
/* fmt has already been adjusted if needed */
while (*fmt) {
if (!might_format) {
if (*fmt != '%') {
_char_out((int)*fmt);
} else {
might_format = 1;
}
} else {
switch (*fmt) {
case 'z':
case 'l':
case 'h':
/* FIXME: do nothing for these modifiers */
goto still_might_format;
case 'd':
case 'i': {
long d = va_arg(ap, long);
if (d < 0) {
_char_out((int)'-');
d = -d;
}
_printk_dec_ulong(d);
break;
}
case 'u': {
unsigned long u = va_arg(
ap, unsigned long);
_printk_dec_ulong(u);
break;
}
case 'p':
_char_out('0');
_char_out('x');
/* Fall through */
case 'x':
case 'X': {
unsigned long x = va_arg(
ap, unsigned long);
_printk_hex_ulong(x);
break;
}
case 's': {
char *s = va_arg(ap, char *);
while (*s)
_char_out((int)(*s++));
break;
}
case 'c': {
int c = va_arg(ap, int);
_char_out(c);
break;
}
case '%': {
_char_out((int)'%');
break;
}
default:
_char_out((int)'%');
_char_out((int)*fmt);
break;
}
might_format = 0;
}
still_might_format:
++fmt;
}
}
/**
* @brief Output a string
*
* Output a string on output installed by platform at init time. Some
* printf-like formatting is available.
*
* Available formatting:
* - %x/%X: outputs a 32-bit number in ABCDWXYZ format. All eight digits
* are printed: if less than 8 characters are needed, leading zeroes
* are displayed.
* - %s: output a null-terminated string
* - %p: pointer, same as %x
* - %d/%i/%u: outputs a 32-bit number in unsigned decimal format.
*
* @param fmt formatted string to output
*
* @return N/A
*/
void printk(const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
_vprintk(fmt, ap);
va_end(ap);
}
/**
* @brief Output an unsigned long in hex format
*
* Output an unsigned long on output installed by platform at init time. Should
* be able to handle an unsigned long of any size, 32 or 64 bit.
* @param num Number to output
*
* @return N/A
*/
static void _printk_hex_ulong(const unsigned long num)
{
int size = sizeof(num) * 2;
for (; size; size--) {
char nibble = (num >> ((size - 1) << 2) & 0xf);
nibble += nibble > 9 ? 87 : 48;
_char_out((int)nibble);
}
}
/**
* @brief Output an unsigned long (32-bit) in decimal format
*
* Output an unsigned long on output installed by platform at init time. Only
* works with 32-bit values.
* @param num Number to output
*
* @return N/A
*/
static void _printk_dec_ulong(const unsigned long num)
{
unsigned long pos = 999999999;
unsigned long remainder = num;
int found_largest_digit = 0;
while (pos >= 9) {
if (found_largest_digit || remainder > pos) {
found_largest_digit = 1;
_char_out((int)((remainder / (pos + 1)) + 48));
}
remainder %= (pos + 1);
pos /= 10;
}
_char_out((int)(remainder + 48));
}
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