lib/tiny-printf.c

   1 /*
   2  * Tiny printf version for SPL
   3  *
   4  * Copied from:
   5  * http://www.sparetimelabs.com/printfrevisited/printfrevisited.php
   6  *
   7  * Copyright (C) 2004,2008  Kustaa Nyholm
   8  *
   9  * SPDX-License-Identifier:     LGPL-2.1+
  10  */
  11
  12 #include <common.h>
  13 #include <stdarg.h>
  14 #include <serial.h>
  15
  16 static char *bf;
  17 static char buf[12];
  18 static unsigned int num;
  19 static char uc;
  20 static char zs;
  21
  22 static void out(char c)
  23 {
  24         *bf++ = c;
  25 }
  26
  27 static void out_dgt(char dgt)
  28 {
  29         out(dgt + (dgt < 10 ? '0' : (uc ? 'A' : 'a') - 10));
  30         zs = 1;
  31 }
  32
  33 static void div_out(unsigned int div)
  34 {
  35         unsigned char dgt = 0;
  36
  37         num &= 0xffff; /* just for testing the code with 32 bit ints */
  38         while (num >= div) {
  39                 num -= div;
  40                 dgt++;
  41         }
  42
  43         if (zs || dgt > 0)
  44                 out_dgt(dgt);
  45 }
  46
  47 int printf(const char *fmt, ...)
  48 {
  49         va_list va;
  50         char ch;
  51         char *p;
  52
  53         va_start(va, fmt);
  54
  55         while ((ch = *(fmt++))) {
  56                 if (ch != '%') {
  57                         putc(ch);
  58                 } else {
  59                         char lz = 0;
  60                         char w = 0;
  61
  62                         ch = *(fmt++);
  63                         if (ch == '0') {
  64                                 ch = *(fmt++);
  65                                 lz = 1;
  66                         }
  67
  68                         if (ch >= '0' && ch <= '9') {
  69                                 w = 0;
  70                                 while (ch >= '0' && ch <= '9') {
  71                                         w = (((w << 2) + w) << 1) + ch - '0';
  72                                         ch = *fmt++;
  73                                 }
  74                         }
  75                         bf = buf;
  76                         p = bf;
  77                         zs = 0;
  78
  79                         switch (ch) {
  80                         case 0:
  81                                 goto abort;
  82                         case 'u':
  83                         case 'd':
  84                                 num = va_arg(va, unsigned int);
  85                                 if (ch == 'd' && (int)num < 0) {
  86                                         num = -(int)num;
  87                                         out('-');
  88                                 }
  89                                 div_out(10000);
  90                                 div_out(1000);
  91                                 div_out(100);
  92                                 div_out(10);
  93                                 out_dgt(num);
  94                                 break;
  95                         case 'x':
  96                         case 'X':
  97                                 uc = ch == 'X';
  98                                 num = va_arg(va, unsigned int);
  99                                 div_out(0x1000);
 100                                 div_out(0x100);
 101                                 div_out(0x10);
 102                                 out_dgt(num);
 103                                 break;
 104                         case 'c':
 105                                 out((char)(va_arg(va, int)));
 106                                 break;
 107                         case 's':
 108                                 p = va_arg(va, char*);
 109                                 break;
 110                         case '%':
 111                                 out('%');
 112                         default:
 113                                 break;
 114                         }
 115
 116                         *bf = 0;
 117                         bf = p;
 118                         while (*bf++ && w > 0)
 119                                 w--;
 120                         while (w-- > 0)
 121                                 putc(lz ? '0' : ' ');
 122                         while ((ch = *p++))
 123                                 putc(ch);
 124                 }
 125         }
 126
 127 abort:
 128         va_end(va);
 129         return 0;
 130 }