xcall ABOX, srow, scol, height, width {,opcode}
ABOX is one of the many routines which draw boxes—among which, MSBOXX would be the most sophisticated and generally preferred. Note that ABOX draws the box at the specified position rather than around it.
Parameters
srow, scol [in]
starting row and position
height, width [in]
(not ending row/column)
opcode [in/out]
Without an opcode, the default, ABOX will just draw the box border. If opcode is specified and non-zero, the interior of the box will also be cleared. On return, opcode will be set to the number of bytes written, or less than zero for errors
