print cpuid info

cpuid.c

/*
 * Copyright (c) 2012, Ben Noordhuis <info@bnoordhuis.nl>
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>

static void cpuid(uint32_t cmd, uint32_t vals[4])
{
  __asm__ __volatile__ (
    "cpuid"
    : "=a" (vals[0]),
      "=b" (vals[1]),
      "=c" (vals[2]),
      "=d" (vals[3])
    : "a" (cmd)
  );
}

static int istext(char c)
{
  return (c >= '0' && c <= '9')
      || (c >= 'A' && c <= 'Z')
      || (c >= 'a' && c <= 'z');
}

static char totext(char c)
{
  return istext(c) ? c : '.';
}

static const char *dec2text(uint32_t val, char buf[5])
{
  buf[0] = totext(val & 255);
  buf[1] = totext((val >> 8) & 255);
  buf[2] = totext((val >> 16) & 255);
  buf[3] = totext((val >> 24) & 255);
  buf[4] = '\0';
  return buf;
}

static const char *dec2bin(uint32_t val, char buf[50])
{
  int i, k;

  for (i = 0, k = 31; k >= 0; i++, k--) {
    buf[i] = '0' + !!(val & (1 << k));
    if (k != 0 && k % 8 == 0) buf[++i] = ' ';
  }
  buf[i] = '\0';

  return buf;
}

int main(int argc, char **argv)
{
  uint32_t vals[4] = { 0, 0, 0, 0 };
  char text[20];
  char bin[200];

  cpuid(argv[1] ? atoi(argv[1]) : 0, vals);
  printf("eax %08x %s %s\n"
         "ebx %08x %s %s\n"
         "ecx %08x %s %s\n"
         "edx %08x %s %s\n",
         vals[0], dec2text(vals[0], text + 0), dec2bin(vals[0], bin + 0),
         vals[1], dec2text(vals[1], text + 5), dec2bin(vals[1], bin + 50),
         vals[2], dec2text(vals[2], text + 10), dec2bin(vals[2], bin + 100),
         vals[3], dec2text(vals[3], text + 15), dec2bin(vals[3], bin + 150));

  return 0;
}