CHAR PLOT
CHAR PLOT is a routine which enables one to use the Calcomp plotter as an output typewriter. This program is stored as CHPLOT BIN [English CHAR PLOT]. In use a code, representing a character of command as defined in Appendix I, is placed into accumulator C. Upon calling the routine the plotter will, either print a character, or set itself into one of several modes. The input to the routine is a word whose 8 low order bits contain a code and whose sign bit must be 0. The routine is entered by MOVE C, [WORD], PUSHJ P, PLOTC. A word=O stops everything and initiates the system. Note: The program starts off in lower case mode. While it is in this mode any attempt to issue a lower-case code causes the computer to hang up. It is suggested that the first call be used to set the routine to upper case and the 8th bit in the code used to shift between upper and lower cases. The symbols P,C and CRKCHN are global and user-defined. Other symbols are PLOTC (Normal entry point), UCTAB (Beginning of lower case table.), LCTAB (Beginning of lower case table, CLNGTH (Routine which returns length of the character which was its argument in Acc. C.