Use this directive to declare the number of lines—and, optionally, the number of columns—to use for each page, when generating listings.
If you do not use .psize, listings use a default line-count of 60. You may omit the comma and columns specification; the default width is 200 columns.
The assembler generates form feeds whenever the specified number of lines is exceeded (or whenever you explicitly request one, using .eject).
If you specify lines as 0, no form feeds are generated save those explicitly specified with .eject.