#define _LARGEFILE64_SOURCE
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/errno.h>

static int _msr_open(void)
{
  static int msrfd = 0;

  if (msrfd == 0) {
    msrfd = open("/dev/cpu/0/msr", O_RDWR);
    if (msrfd == -1)
      ErrorF("Unable to open /dev/cpu/0/msr: %d\n", errno);
  }

  return msrfd;
}

int GeodeReadMSR(unsigned long addr, unsigned long *lo, unsigned long *hi)
{
  unsigned int data[2];
  int fd = _msr_open();
  int ret;

  if (fd == -1)
    return -1;
  
  ret = lseek64(fd, (off64_t) addr, SEEK_SET);
  
  if (ret == -1)
    return -1;
  
  ret = read(fd, (void *) data, sizeof(data));
  
  if (ret != 8) 
    return -1;

  *hi = data[1];
  *lo = data[0];

  return 0;
}

int GeodeWriteMSR(unsigned long addr, unsigned long lo, unsigned long hi)
{
  unsigned int data[2];
  int fd = _msr_open();

  if (fd == -1)
    return - 1;

  if (lseek64(fd, (off64_t) addr, SEEK_SET) == -1)
    return -1;

  data[0] = lo;
  data[1] = hi;

  if (write(fd, (void *) data, 8) != 8)
    return -1;

  return 0;
}