IBM 3164 ASCII Manual page 155

Chapter 5. Programming considerations
5-68
If the host program changes a line from single-width to double-width after the
C
operator has entered data, all characters previously displayed at the right- hand .
side of the viewport are lost. The following figure illustrates the concept of
double-width operation.
1 " " ' - - 1
--1~1
abcdefghijklmn •
abc
d • ., 9
123456789012 123456789012
Before After
If the number of columns in the viewport is odd and the window reaches the
rightmost position, the rightmost column is converted to a null character in the
viewport. If the window is not located at the rightmost p'osition, the left half
of the double-width character appears at the rightmost column in the
viewport. The following figure shows an example.
1 " - - - 1
--l===h
abcdefghijklmn - - - . . .
abcdefg
123456789012 123456789012
Before
After