arch/x86/boot/printf.c

   1 /* -*- linux-c -*- ------------------------------------------------------- *
   2  *
   3  *   Copyright (C) 1991, 1992 Linus Torvalds
   4  *   Copyright 2007 rPath, Inc. - All Rights Reserved
   5  *
   6  *   This file is part of the Linux kernel, and is made available under
   7  *   the terms of the GNU General Public License version 2.
   8  *
   9  * ----------------------------------------------------------------------- */
  10
  11 /*
  12  * arch/i386/boot/printf.c
  13  *
  14  * Oh, it's a waste of space, but oh-so-yummy for debugging.  This
  15  * version of printf() does not include 64-bit support.  "Live with
  16  * it."
  17  *
  18  */
  19
  20 #include "boot.h"
  21
  22 static int skip_atoi(const char **s)
  23 {
  24         int i = 0;
  25
  26         while (isdigit(**s))
  27                 i = i * 10 + *((*s)++) - '0';
  28         return i;
  29 }
  30
  31 #define ZEROPAD 1               /* pad with zero */
  32 #define SIGN    2               /* unsigned/signed long */
  33 #define PLUS    4               /* show plus */
  34 #define SPACE   8               /* space if plus */
  35 #define LEFT    16              /* left justified */
  36 #define SPECIAL 32              /* 0x */
  37 #define LARGE   64              /* use 'ABCDEF' instead of 'abcdef' */
  38
  39 #define do_div(n,base) ({ \
  40 int __res; \
  41 __res = ((unsigned long) n) % (unsigned) base; \
  42 n = ((unsigned long) n) / (unsigned) base; \
  43 __res; })
  44
  45 static char *number(char *str, long num, int base, int size, int precision,
  46                     int type)
  47 {
  48         char c, sign, tmp[66];
  49         const char *digits = "0123456789abcdefghijklmnopqrstuvwxyz";
  50         int i;
  51
  52         if (type & LARGE)
  53                 digits = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
  54         if (type & LEFT)
  55                 type &= ~ZEROPAD;
  56         if (base < 2 || base > 36)
  57                 return 0;
  58         c = (type & ZEROPAD) ? '0' : ' ';
  59         sign = 0;
  60         if (type & SIGN) {
  61                 if (num < 0) {
  62                         sign = '-';
  63                         num = -num;
  64                         size--;
  65                 } else if (type & PLUS) {
  66                         sign = '+';
  67                         size--;
  68                 } else if (type & SPACE) {
  69                         sign = ' ';
  70                         size--;
  71                 }
  72         }
  73         if (type & SPECIAL) {
  74                 if (base == 16)
  75                         size -= 2;
  76                 else if (base == 8)
  77                         size--;
  78         }
  79         i = 0;
  80         if (num == 0)
  81                 tmp[i++] = '0';
  82         else
  83                 while (num != 0)
  84                         tmp[i++] = digits[do_div(num, base)];
  85         if (i > precision)
  86                 precision = i;
  87         size -= precision;
  88         if (!(type & (ZEROPAD + LEFT)))
  89                 while (size-- > 0)
  90                         *str++ = ' ';
  91         if (sign)
  92                 *str++ = sign;
  93         if (type & SPECIAL) {
  94                 if (base == 8)
  95                         *str++ = '0';
  96                 else if (base == 16) {
  97                         *str++ = '0';
  98                         *str++ = digits[33];
  99                 }
 100         }
 101         if (!(type & LEFT))
 102                 while (size-- > 0)
 103                         *str++ = c;
 104         while (i < precision--)
 105                 *str++ = '0';
 106         while (i-- > 0)
 107                 *str++ = tmp[i];
 108         while (size-- > 0)
 109                 *str++ = ' ';
 110         return str;
 111 }
 112
 113 int vsprintf(char *buf, const char *fmt, va_list args)
 114 {
 115         int len;
 116         unsigned long num;
 117         int i, base;
 118         char *str;
 119         const char *s;
 120
 121         int flags;              /* flags to number() */
 122
 123         int field_width;        /* width of output field */
 124         int precision;          /* min. # of digits for integers; max
 125                                    number of chars for from string */
 126         int qualifier;          /* 'h', 'l', or 'L' for integer fields */
 127
 128         for (str = buf; *fmt; ++fmt) {
 129                 if (*fmt != '%') {
 130                         *str++ = *fmt;
 131                         continue;
 132                 }
 133
 134                 /* process flags */
 135                 flags = 0;
 136               repeat:
 137                 ++fmt;          /* this also skips first '%' */
 138                 switch (*fmt) {
 139                 case '-':
 140                         flags |= LEFT;
 141                         goto repeat;
 142                 case '+':
 143                         flags |= PLUS;
 144                         goto repeat;
 145                 case ' ':
 146                         flags |= SPACE;
 147                         goto repeat;
 148                 case '#':
 149                         flags |= SPECIAL;
 150                         goto repeat;
 151                 case '0':
 152                         flags |= ZEROPAD;
 153                         goto repeat;
 154                 }
 155
 156                 /* get field width */
 157                 field_width = -1;
 158                 if (isdigit(*fmt))
 159                         field_width = skip_atoi(&fmt);
 160                 else if (*fmt == '*') {
 161                         ++fmt;
 162                         /* it's the next argument */
 163                         field_width = va_arg(args, int);
 164                         if (field_width < 0) {
 165                                 field_width = -field_width;
 166                                 flags |= LEFT;
 167                         }
 168                 }
 169
 170                 /* get the precision */
 171                 precision = -1;
 172                 if (*fmt == '.') {
 173                         ++fmt;
 174                         if (isdigit(*fmt))
 175                                 precision = skip_atoi(&fmt);
 176                         else if (*fmt == '*') {
 177                                 ++fmt;
 178                                 /* it's the next argument */
 179                                 precision = va_arg(args, int);
 180                         }
 181                         if (precision < 0)
 182                                 precision = 0;
 183                 }
 184
 185                 /* get the conversion qualifier */
 186                 qualifier = -1;
 187                 if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L') {
 188                         qualifier = *fmt;
 189                         ++fmt;
 190                 }
 191
 192                 /* default base */
 193                 base = 10;
 194
 195                 switch (*fmt) {
 196                 case 'c':
 197                         if (!(flags & LEFT))
 198                                 while (--field_width > 0)
 199                                         *str++ = ' ';
 200                         *str++ = (unsigned char)va_arg(args, int);
 201                         while (--field_width > 0)
 202                                 *str++ = ' ';
 203                         continue;
 204
 205                 case 's':
 206                         s = va_arg(args, char *);
 207                         len = strnlen(s, precision);
 208
 209                         if (!(flags & LEFT))
 210                                 while (len < field_width--)
 211                                         *str++ = ' ';
 212                         for (i = 0; i < len; ++i)
 213                                 *str++ = *s++;
 214                         while (len < field_width--)
 215                                 *str++ = ' ';
 216                         continue;
 217
 218                 case 'p':
 219                         if (field_width == -1) {
 220                                 field_width = 2 * sizeof(void *);
 221                                 flags |= ZEROPAD;
 222                         }
 223                         str = number(str,
 224                                      (unsigned long)va_arg(args, void *), 16,
 225                                      field_width, precision, flags);
 226                         continue;
 227
 228                 case 'n':
 229                         if (qualifier == 'l') {
 230                                 long *ip = va_arg(args, long *);
 231                                 *ip = (str - buf);
 232                         } else {
 233                                 int *ip = va_arg(args, int *);
 234                                 *ip = (str - buf);
 235                         }
 236                         continue;
 237
 238                 case '%':
 239                         *str++ = '%';
 240                         continue;
 241
 242                         /* integer number formats - set up the flags and "break" */
 243                 case 'o':
 244                         base = 8;
 245                         break;
 246
 247                 case 'X':
 248                         flags |= LARGE;
 249                 case 'x':
 250                         base = 16;
 251                         break;
 252
 253                 case 'd':
 254                 case 'i':
 255                         flags |= SIGN;
 256                 case 'u':
 257                         break;
 258
 259                 default:
 260                         *str++ = '%';
 261                         if (*fmt)
 262                                 *str++ = *fmt;
 263                         else
 264                                 --fmt;
 265                         continue;
 266                 }
 267                 if (qualifier == 'l')
 268                         num = va_arg(args, unsigned long);
 269                 else if (qualifier == 'h') {
 270                         num = (unsigned short)va_arg(args, int);
 271                         if (flags & SIGN)
 272                                 num = (short)num;
 273                 } else if (flags & SIGN)
 274                         num = va_arg(args, int);
 275                 else
 276                         num = va_arg(args, unsigned int);
 277                 str = number(str, num, base, field_width, precision, flags);
 278         }
 279         *str = '\0';
 280         return str - buf;
 281 }
 282
 283 int sprintf(char *buf, const char *fmt, ...)
 284 {
 285         va_list args;
 286         int i;
 287
 288         va_start(args, fmt);
 289         i = vsprintf(buf, fmt, args);
 290         va_end(args);
 291         return i;
 292 }
 293
 294 int printf(const char *fmt, ...)
 295 {
 296         char printf_buf[1024];
 297         va_list args;
 298         int printed;
 299
 300         va_start(args, fmt);
 301         printed = vsprintf(printf_buf, fmt, args);
 302         va_end(args);
 303
 304         puts(printf_buf);
 305
 306         return printed;
 307 }