//printf needs following syscalls: sbrk write close fstat isatty lseek read
//

#include <sys/stat.h>

int close(int file) 
{
   return -1;
}

int fstat(int file, struct stat *st)
{
    st->st_mode = S_IFCHR;
    return 0;
}

int isatty(int file) {
    return 1;
}

int lseek(int file, int ptr, int dir) {
    return 0;
}

int read(int file, char *ptr, int len) {
    return 0;
}
    int open(const char *name, int flags, int mode) {
	            return -1;
		              }


int write(int file, char *ptr, int len) 
{

    int todo;
    for (todo = 0; todo < len; todo++) 
    {

	char byte=(*ptr++);
        int byt=byte;

	int ebx; // will hold return value;
	// system call 
	asm("pusha");
	asm("mov $61,%eax"); // select syscall)

	asm("mov %0,%%edx"::"m"(byt));
	//asm("mov $88,%edx");

	asm("int $0x80"); // actual syscall ! interrupt
        asm("mov %%ebx, %0": "=b" (ebx));
	asm("popa");
	//
	
    }
    return len;
}

caddr_t sbrk(int incr) 
{
	    
//            extern char _end;		/* Defined by the linker */
	    char _end;
            static char *heap_end;
            char *prev_heap_end;
          
            if (heap_end == 0) {
              heap_end = &_end;
            }
            prev_heap_end = heap_end;
	    /*
            if (heap_end + incr > stack_ptr) {
              write (1, "Heap and stack collision\n", 25);
              abort ();
            }
	    */
          
            heap_end += incr;
            return (caddr_t) prev_heap_end;
}

//