TM 1-1510-225-10 3C-20 The  CR key advances the cursor to the start of the next line.  If the cursor was in any location on the last line, pressing the CR key will position the cursor to the   start   of   the   first   line   in   the   data   entry   region (column  2,  line  3).    The  HC key returns the cursor to the   start   of   the   first   line   in   the   data   entry   region (column 2, line 3). (20)   Calculator  Mode.    Only  the  numeric,  ¬, ®,  HC,  period,  and  mode  keys  and  the  keys  printed with   alternate   functions   on   the   keyboard   face   are active during the calculator mode. If the calculator mode is selected for any of the three  pilot-input pages after power on initialization, an asterisk will display in column 1, line 2 and a separator (Ù ) in red will display in its standard position in column 11,   line   2.   Line   2   is   the   numeric   entry   line   in   the calculator  mode.    The  separator  marks  the  extent  of the  number  that  can  be  entered  to  the  right  of  the separator. (a)  Numeric    Keys,    Period,    and    Sign Change.    Each  time  a  numeric  key  is  pressed,  the number    displays    in    the    rightmost    location    of    the numeric  entry  line.    Any  previously  entered  data  is shifted  to  the  left.    A  number  can  include  a  decimal point (period) and a sign.  Numbers can be entered to within  one  space  to  the  right  of  the  separator.    This space   is   reserved   for   the   sign   when   a   maximum number of digits is entered.  All numbers are assumed to be positive as they are entered.  A positive  number has a space rather than a + sign preceding it, whereas a  negative  number  has  a   –  as  the  leading  character.   After a number is entered, the sign can be changed by pressing  the  V  key  whose  alternate  function  is  shown as "+/-" for the calculator mode.  If an attempt is made to enter a number that is too large to fit to the right of the separator, the leftmost character will be lost as the new character enters from the right. (b)  Enter  Function.    When  the   U  key  is pressed, the enter function is requested.  By using the enter  function,  up  to  10  lines  of  information  can  be restored  on  the  screen  below  the  numeric  entry  line.   These 10 storage lines are referred to as a data stack.   The asterisk in column 1 indicates the beginning of the stack.  The line following the asterisk is the end of the stack.  Each time the enter function is requested, the end  of  the  stack  is  cleared  and  all  the  data  on  the screen    down    through    the    beginning    of    the    stack (designated   by   the   asterisk   in   column   1)   is   moved down one line, leaving the numeric entry line cleared. When  the  beginning  of  the  stack  reaches  the  last  line on the screen, no more data can be entered into the stack. (c)  Roll Up.  When the  P key is pressed, the  roll  up  function  is  requested.    The  roll  up  function rolls all the data on the numeric entry line down to the bottom  of  the  page,  and  moves  all  the  other  data  on the screen up one line. (d)  Exchange Function.  When the W key is  pressed,  the  exchange  function  is  requested.    This function exchanges only the number to the right of the separator on the numeric entry line with the number on the next (third) line. (e)  Clear  Entry  Function.    When the   S  key  is  pressed,  the  clear  entry  function  is  requested.   this function clears only the number to the right of the separator  on  the  numeric  entry  line.    No  other  data  is affected. (f)   Delete  Line    Function.    When  the   X  key  is  pressed,  the  delete  line  function  is  requested.   This function deletes all the data on the numeric entry line  and  moves  the  data  on  the  bottom  line  of  the screen to the numeric entry line.  All the lines from the end of the stack (the line following the asterisk) to the bottom of the page are moved down by one line and a blank line is entered at the end of the stack. If  the  beginning  of  the  stack  (identified  by  an asterisk  in  column  1)  is  at  the  bottom  of  the  page,  no action    occurs    when    the    delete    line    function    is requested.        In    this    case,    the    numeric    entry    line contains  the  end  of  the  stack  whose  number  can  be cleared by pressing CLE. (g)  Beginning  Of  Stack  (BOS)  Function. When the   CR  key  is  pressed,  the  BOS  function  is requested.    This  function  rolls  up  each  line  on  the screen until the beginning of stack line displays in the numeric entry line. (h)  Set Beginning of Stack (SBS) Function.      When   the   Y   key   is   pressed,   the   SBS function is requested.  When this function is requested, the  asterisk  designating  the  beginning  of  the  stack  is cleared  from  its  current  position  and  set  to  column  1 line 2, the numeric entry line. (i)   Add  Operation.    When  the    Z  key  is pressed,   this   operation   adds   the    number    on    the numeric entry line to the number on the third line and replaces  the  number  on  the  third  line  with  the  result.   The number on the numeric entry line is cleared. (j)   Subtract  Operation.    When  the   -  key is pressed, this operation subtracts the number on the numeric  entry  line  from  the  number  on  the  third  line and  replaces  the  number  on  the  third  line  with  the