149 lines
3.7 KiB
C
149 lines
3.7 KiB
C
#include <sys/stat.h>
|
|
#include <errno.h>
|
|
|
|
|
|
#include <errno.h>
|
|
#undef errno
|
|
extern int errno;
|
|
|
|
|
|
/**
|
|
* This will execute an ebreak instruction and assume that the
|
|
* CPU will halt or simulation environment will terminate.
|
|
*****************************************************************/
|
|
void _exit(int i)
|
|
{
|
|
asm volatile (" ebreak ");
|
|
}
|
|
|
|
/**
|
|
* It is assumed that there is exactly only process running and that
|
|
* it does not support signals. Therefore calling this is effectively
|
|
* illegal and will therefore execute an ebreak instruction.
|
|
*****************************************************************/
|
|
void _kill(int pid)
|
|
{
|
|
#if 1
|
|
asm volatile (" ebreak ");
|
|
#else
|
|
return; // arguably, this might also be acceptable
|
|
#endif
|
|
}
|
|
|
|
/**
|
|
* This returns the process ID of the runnung program.
|
|
* This library assumes that there is only process that
|
|
* can ever run.
|
|
*
|
|
* @return 1
|
|
*****************************************************************/
|
|
int _getpid(void)
|
|
{
|
|
return 1;
|
|
}
|
|
|
|
|
|
/**
|
|
* This library does not support any file I/O of any kind.
|
|
*
|
|
* @return -1 Indicating that file could not be closed.
|
|
*****************************************************************/
|
|
int _close(int file)
|
|
{
|
|
errno = EBADF;
|
|
return -1;
|
|
}
|
|
|
|
/**
|
|
* This library does not support any file I/O of any kind.
|
|
* This call will return a status indicating that the file
|
|
* in question is a character device.
|
|
*
|
|
* @return 0 Indicating that the call has succeeded.
|
|
*****************************************************************/
|
|
int _fstat(int file, struct stat *st)
|
|
{
|
|
st->st_mode = S_IFCHR;
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* This library does not support any file I/O of any kind.
|
|
*
|
|
* @return 1 Indicating that file is a tty device (a terminal.)
|
|
*****************************************************************/
|
|
int _isatty(int file)
|
|
{
|
|
return 1;
|
|
}
|
|
|
|
/**
|
|
* This library does not support any file I/O of any kind.
|
|
*
|
|
* @return 0 Indicating that the request has succeeded.
|
|
*****************************************************************/
|
|
int _lseek(int file, int ptr, int dir)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* This library does not support any file I/O of any kind.
|
|
*
|
|
* @return -1 (error codition.)
|
|
*****************************************************************/
|
|
int _open(const char *name, int flags, int mode)
|
|
{
|
|
errno = ENFILE; // The system-wide limit (0) on total open files has been reached.
|
|
return -1;
|
|
}
|
|
|
|
/**
|
|
* This library does not support any file I/O of any kind.
|
|
*
|
|
* @return EOF.
|
|
*****************************************************************/
|
|
int _read(int file, char *ptr, int len)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* This function should satify the caller by simply returning len
|
|
* indicating that the write has succeeded as requested in spite
|
|
* of the fact that the data is simply ignored/discarded.
|
|
*
|
|
* @return len
|
|
*****************************************************************/
|
|
int _write(int file, char *ptr, int len)
|
|
{
|
|
return len;
|
|
}
|
|
|
|
/**
|
|
* Adjust the brk pointer up or down as requested.
|
|
*
|
|
* The initial brk address is set to _end (the end of the BSS).
|
|
* Any requests to adjust the brk will be performed without any
|
|
* error checking.
|
|
*
|
|
* @param delta The number of bytes to raise or lower the brk.
|
|
*
|
|
* @return The address that brk was set to before adjusting it by
|
|
* delta. Note that when delta is positive, this will return the
|
|
* address of the newly allocated region of memory.
|
|
*
|
|
* @bug It is possible that an errant program could call this and
|
|
* reduce the brk such that it points below _end or increase the
|
|
* brk to the point that it overlaps the stack.
|
|
*****************************************************************/
|
|
char *_sbrk (int delta)
|
|
{
|
|
extern char _end[];
|
|
static char *end_of_data = _end;
|
|
|
|
char *ptr = end_of_data;
|
|
end_of_data += delta;
|
|
return ptr;
|
|
}
|