GCHQ Stage 2 Solution - VM code translated to C

#include <stdio.h>


char buf[4096];

int main() {
int x = 170, i=0, r2=0;;

// decode next decrypt code
  FILE *in = fopen("dump.bin", "r"); // file to open (vm code dump)
  fread(buf, 4096, 1, in);
  for(i=0x100; i<0x100+0x80; i++)
  {
    char c = buf[i];
    printf("%c", c^x);
    x++;
  }

// decrypt next sequence (GET)
  r2=0;
  x = 50;
  char c;
  do {
    c = buf[0x1c0 + r2];
    c ^= x;
    buf[0x1c0+r2] = c;
    r2++;
    x+=3;
    //if(r2==0) jump x
  } while (c!=0 && r2 < sizeof(buf));

  for(i = 0; i<4096; i++)
    printf("%c", buf[i]);
}