特別版No.4　第★章　サポートページ

Pico RV32とlwIPでTCP/IP通信を試す

●pingの実行結果

$ ping -c3 192.168.1.2
PING 192.168.1.2 (192.168.1.2) 56(84) bytes of data.
64 bytes from 192.168.1.2: icmp_seq=1 ttl=255 time=88.4 ms
64 bytes from 192.168.1.2: icmp_seq=2 ttl=255 time=47.8 ms
64 bytes from 192.168.1.2: icmp_seq=3 ttl=255 time=47.8 ms

--- 192.168.1.2 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2003ms
rtt min/avg/max/mdev = 47.804/61.337/88.395/19.132 ms

●自作したprintf関数（my_printf.c）

#include <stdarg.h>

#include "addresses.h"
#include "my_printf.h"

void my_printf_init() {
  const uint32_t CLOCK_HZ = 25000000; // クロック周波数
  const uint32_t BAUD_RATE = 115200;  // UARTのボー・レートを設定
  *UART_CLKDIV = CLOCK_HZ / BAUD_RATE;
}

int putchar(int c) {
  if (c == '\n') {
    *UART_DATA = '\r';
  }
  *UART_DATA = c;
  return c;
}

static void __attribute__((optimize("Os"))) my_printchar(char **str, int c)
{
  extern int putchar(int c);

  if (str) {
    **str = c;
    ++(*str);
  }
  else (void)putchar(c);
}

#define PAD_RIGHT 1
#define PAD_ZERO 2

static int __attribute__((optimize("Os"))) my_prints(char **out, const char *string, int width, int pad)
{
  register int pc = 0, padchar = ' ';

  if (width > 0) {
    register int len = 0;
    register const char *ptr;
    for (ptr = string; *ptr; ++ptr) ++len;
    if (len >= width) width = 0;
    else width -= len;
    if (pad & PAD_ZERO) padchar = '0';
  }
  if (!(pad & PAD_RIGHT)) {
    for ( ; width > 0; --width) {
      my_printchar (out, padchar);
      ++pc;
    }
  }
  for ( ; *string ; ++string) {
    my_printchar (out, *string);
    ++pc;
  }
  for ( ; width > 0; --width) {
    my_printchar (out, padchar);
    ++pc;
  }

  return pc;
}

/* The following should be enough for 32 bit int */
#define PRINT_BUF_LEN 12

static int __attribute__((optimize("Os"))) my_printi(char **out, int i, int b, int sg, int width, int pad, int letbase)
{
  char print_buf[PRINT_BUF_LEN];
  register char *s;
  register int t, neg = 0, pc = 0;
  register unsigned int u = i;

  if (i == 0) {
    print_buf[0] = '0';
    print_buf[1] = '\0';
    return my_prints (out, print_buf, width, pad);
  }

  if (sg && b == 10 && i < 0) {
    neg = 1;
    u = -i;
  }

  s = print_buf + PRINT_BUF_LEN-1;
  *s = '\0';

  while (u) {
    t = u % b;
    if( t >= 10 )
      t += letbase - '0' - 10;
    *--s = t + '0';
    u /= b;
  }

  if (neg) {
    if( width && (pad & PAD_ZERO) ) {
      my_printchar (out, '-');
      ++pc;
      --width;
    }
    else {
      *--s = '-';
    }
  }

  return pc + my_prints (out, s, width, pad);
}

static int my_print( char **out, const char *format, va_list args )
{
  register int width, pad;
  register int pc = 0;
  char scr[2];

  for (; *format != 0; ++format) {
    if (*format == '%') {
      ++format;
      width = pad = 0;
      if (*format == '\0') break;
      if (*format == '%') goto out;
      if (*format == '-') {
        ++format;
        pad = PAD_RIGHT;
      }
      while (*format == '0') {
        ++format;
        pad |= PAD_ZERO;
      }
      for ( ; *format >= '0' && *format <= '9'; ++format) {
        width *= 10;
        width += *format - '0';
      }
      if( *format == 's' ) {
        register char *s = (char *)((long)va_arg( args, int ));
        pc += my_prints (out, s?s:"(null)", width, pad);
        continue;
      }
      if( *format == 'd' ) {
        pc += my_printi (out, va_arg( args, int ), 10, 1, width, pad, 'a');
        continue;
      }
      if( *format == 'x' ) {
        pc += my_printi (out, va_arg( args, int ), 16, 0, width, pad, 'a');
        continue;
      }
      if( *format == 'X' ) {
        pc += my_printi (out, va_arg( args, int ), 16, 0, width, pad, 'A');
        continue;
      }
      if( *format == 'u' ) {
        pc += my_printi (out, va_arg( args, int ), 10, 0, width, pad, 'a');
        continue;
      }
      if( *format == 'c' ) {
        /* char are converted to int then pushed on the stack */
        scr[0] = (char)va_arg( args, int );
        scr[1] = '\0';
        pc += my_prints (out, scr, width, pad);
        continue;
      }
    }
    else {
    out:
      my_printchar (out, *format);
      ++pc;
    }
  }
  if (out) **out = '\0';
  va_end( args );
  return pc;
}

int my_printf(const char *format, ...)
{
  va_list args;

  va_start( args, format );
  return my_print( 0, format, args );
}