Sharp mz-3500 Manual For Use page 204

Section A:
System interface
If the attributes could successfully be set as specified,
are set to
@
upon return.
If
the file was not found,
A
is
and
H
to
0.
both
A
and
H
set to 0FFH
Physical
mode.
In
code.
errors are treated according to the specified error handling
case of return, A is set to 0FFH and H holds the physical error
EOS System manual
Daeumling & Zimmermann
Page 67