![H. Peter Anvin](/assets/img/avatar_default.png)
This implements writing text to the console, including printf(). Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
308 lines
5.8 KiB
C
308 lines
5.8 KiB
C
/* -*- linux-c -*- ------------------------------------------------------- *
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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* Copyright 2007 rPath, Inc. - All Rights Reserved
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*
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* This file is part of the Linux kernel, and is made available under
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* the terms of the GNU General Public License version 2.
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*
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* ----------------------------------------------------------------------- */
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/*
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* arch/i386/boot/printf.c
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*
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* Oh, it's a waste of space, but oh-so-yummy for debugging. This
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* version of printf() does not include 64-bit support. "Live with
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* it."
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*
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*/
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#include "boot.h"
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static int skip_atoi(const char **s)
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{
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int i = 0;
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while (isdigit(**s))
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i = i * 10 + *((*s)++) - '0';
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return i;
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}
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#define ZEROPAD 1 /* pad with zero */
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#define SIGN 2 /* unsigned/signed long */
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#define PLUS 4 /* show plus */
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#define SPACE 8 /* space if plus */
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#define LEFT 16 /* left justified */
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#define SPECIAL 32 /* 0x */
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#define LARGE 64 /* use 'ABCDEF' instead of 'abcdef' */
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#define do_div(n,base) ({ \
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int __res; \
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__res = ((unsigned long) n) % (unsigned) base; \
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n = ((unsigned long) n) / (unsigned) base; \
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__res; })
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static char *number(char *str, long num, int base, int size, int precision,
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int type)
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{
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char c, sign, tmp[66];
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const char *digits = "0123456789abcdefghijklmnopqrstuvwxyz";
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int i;
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if (type & LARGE)
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digits = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
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if (type & LEFT)
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type &= ~ZEROPAD;
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if (base < 2 || base > 36)
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return 0;
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c = (type & ZEROPAD) ? '0' : ' ';
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sign = 0;
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if (type & SIGN) {
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if (num < 0) {
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sign = '-';
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num = -num;
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size--;
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} else if (type & PLUS) {
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sign = '+';
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size--;
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} else if (type & SPACE) {
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sign = ' ';
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size--;
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}
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}
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if (type & SPECIAL) {
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if (base == 16)
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size -= 2;
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else if (base == 8)
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size--;
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}
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i = 0;
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if (num == 0)
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tmp[i++] = '0';
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else
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while (num != 0)
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tmp[i++] = digits[do_div(num, base)];
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if (i > precision)
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precision = i;
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size -= precision;
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if (!(type & (ZEROPAD + LEFT)))
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while (size-- > 0)
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*str++ = ' ';
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if (sign)
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*str++ = sign;
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if (type & SPECIAL) {
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if (base == 8)
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*str++ = '0';
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else if (base == 16) {
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*str++ = '0';
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*str++ = digits[33];
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}
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}
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if (!(type & LEFT))
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while (size-- > 0)
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*str++ = c;
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while (i < precision--)
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*str++ = '0';
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while (i-- > 0)
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*str++ = tmp[i];
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while (size-- > 0)
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*str++ = ' ';
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return str;
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}
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int vsprintf(char *buf, const char *fmt, va_list args)
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{
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int len;
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unsigned long num;
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int i, base;
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char *str;
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const char *s;
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int flags; /* flags to number() */
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int field_width; /* width of output field */
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int precision; /* min. # of digits for integers; max
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number of chars for from string */
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int qualifier; /* 'h', 'l', or 'L' for integer fields */
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for (str = buf; *fmt; ++fmt) {
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if (*fmt != '%') {
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*str++ = *fmt;
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continue;
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}
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/* process flags */
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flags = 0;
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repeat:
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++fmt; /* this also skips first '%' */
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switch (*fmt) {
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case '-':
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flags |= LEFT;
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goto repeat;
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case '+':
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flags |= PLUS;
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goto repeat;
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case ' ':
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flags |= SPACE;
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goto repeat;
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case '#':
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flags |= SPECIAL;
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goto repeat;
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case '0':
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flags |= ZEROPAD;
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goto repeat;
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}
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/* get field width */
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field_width = -1;
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if (isdigit(*fmt))
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field_width = skip_atoi(&fmt);
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else if (*fmt == '*') {
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++fmt;
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/* it's the next argument */
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field_width = va_arg(args, int);
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if (field_width < 0) {
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field_width = -field_width;
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flags |= LEFT;
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}
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}
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/* get the precision */
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precision = -1;
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if (*fmt == '.') {
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++fmt;
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if (isdigit(*fmt))
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precision = skip_atoi(&fmt);
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else if (*fmt == '*') {
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++fmt;
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/* it's the next argument */
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precision = va_arg(args, int);
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}
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if (precision < 0)
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precision = 0;
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}
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/* get the conversion qualifier */
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qualifier = -1;
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if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L') {
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qualifier = *fmt;
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++fmt;
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}
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/* default base */
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base = 10;
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switch (*fmt) {
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case 'c':
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if (!(flags & LEFT))
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while (--field_width > 0)
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*str++ = ' ';
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*str++ = (unsigned char)va_arg(args, int);
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while (--field_width > 0)
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*str++ = ' ';
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continue;
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case 's':
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s = va_arg(args, char *);
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len = strnlen(s, precision);
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if (!(flags & LEFT))
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while (len < field_width--)
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*str++ = ' ';
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for (i = 0; i < len; ++i)
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*str++ = *s++;
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while (len < field_width--)
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*str++ = ' ';
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continue;
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case 'p':
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if (field_width == -1) {
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field_width = 2 * sizeof(void *);
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flags |= ZEROPAD;
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}
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str = number(str,
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(unsigned long)va_arg(args, void *), 16,
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field_width, precision, flags);
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continue;
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case 'n':
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if (qualifier == 'l') {
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long *ip = va_arg(args, long *);
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*ip = (str - buf);
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} else {
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int *ip = va_arg(args, int *);
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*ip = (str - buf);
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}
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continue;
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case '%':
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*str++ = '%';
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continue;
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/* integer number formats - set up the flags and "break" */
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case 'o':
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base = 8;
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break;
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case 'X':
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flags |= LARGE;
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case 'x':
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base = 16;
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break;
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case 'd':
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case 'i':
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flags |= SIGN;
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case 'u':
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break;
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default:
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*str++ = '%';
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if (*fmt)
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*str++ = *fmt;
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else
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--fmt;
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continue;
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}
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if (qualifier == 'l')
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num = va_arg(args, unsigned long);
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else if (qualifier == 'h') {
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num = (unsigned short)va_arg(args, int);
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if (flags & SIGN)
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num = (short)num;
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} else if (flags & SIGN)
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num = va_arg(args, int);
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else
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num = va_arg(args, unsigned int);
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str = number(str, num, base, field_width, precision, flags);
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}
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*str = '\0';
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return str - buf;
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}
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int sprintf(char *buf, const char *fmt, ...)
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{
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va_list args;
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int i;
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va_start(args, fmt);
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i = vsprintf(buf, fmt, args);
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va_end(args);
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return i;
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}
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int printf(const char *fmt, ...)
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{
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char printf_buf[1024];
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va_list args;
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int printed;
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va_start(args, fmt);
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printed = vsprintf(printf_buf, fmt, args);
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va_end(args);
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puts(printf_buf);
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return printed;
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}
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