c08
I/O support code
Contents|Index|Previous|Next
I/O
support code
Most applications
use calls to the standard C library. However, when you initially link libc.a,
several I/O functions are undefined. If you don’t plan on doing any I/O,
you’re OK; otherwise, you need to create two I/O functions: open()
and close().
These don’t need to be fully supported unless you have a file system, so
they are normally stubbed out, using kill().
sbrk()is
also a stub, since you can’t do process control on an embedded system,
only needed by applications that do dynamic memory allocation. It uses
the variable, _end,
which is set in the linker script.
The
following routines are also used for optimization.
-inbyte
Returns a single byte from
the console.
-outbyte
Used for low-level debugging,
takes an argument for print()
and prints a byte out to the console (typically used for ASCII text).
0