Atari 400 Technical Reference Manual page 53

that logical line from the keyboard. When the [RETURN] ke~ is
pressed, onl~ the keyboard entered characters are sent to the
caller, unless the cursor has been moved out of and then back
into the logical line, in that case all of the logical line will
be sent.
PUT CHARACTER and PUT RECORD
The Handler accepts ATASCII characters as one character per byte.
Sixteen of the 256 ATASCII characters are control codes; the EOL
code has universal meaning, but most of the other control codes
have special meaning only to a display or print device. The
Screen Editor processing of the ATASCII control codes is
explained below:
CLEAR ($70) -- The Screen Editor clears the current display of
all data and the cursor is placed at the home position (upper
left corner of the screen).
CURSOR UP ($lC) -- The cursor moves up by one physical line. The
cursor will wrap from the top line of the display to the bottom
line.
CURSOR DOWN ($10) -- The cursor moves down by one physical line.
The cursor will
wrap
from the bottom line of the display to the
top line.
CURSOR LEFT ($lE) -- The cursor moves left by one column. The
cursor will wrap from the left margin of a line to the right
margin of the same line.
CURSOR RIGHT ($lF) -- The cursor moves right by one column. The
cursor will wrap from the right margin of a line to the left
margin of the same line.
BACKSPACE ($7E) -- The cursor moves left by one column (but never
past the beginning of a logical line), and the character at that
new position is changed to a blank ($20).
OPERATING SYSTEM C016555 -- Section 5
68