Retro1.org codex

*DECK NS$CDA
FUNC NS$CDA(CHAR)U;          # CONVERT DISPLAY CODE CHARACTER TO ASCII #
 
# TITLE NS$CDA - CONVERT DISPLAY CODE CHARACTER TO ASCII.              #
 
      BEGIN    # NS$CDA # 
# 
**    NS$CDA - CONVERT DISPLAY CODE CHARACTER TO ASCII. 
* 
*     J.C. LEE    1981
* 
*     THIS IS A UTILITY FUNCTION SUBPROGRAM.  ITS FUNCTION IS TO
*     CONVERT DISPLAY CODE CHARACTER TO ASCII.
* 
*     FUNC NS$CDA(CHAR) 
* 
*     ENTRY:  
*       CHAR = 6-BIT DISPLAY CODE CHARACTER TO BE CONVERTED.
* 
*     EXIT: 
*       NONE. 
* 
*     METHOD: 
*       USE DISPLAY CODE CHARACTER TO INDEX INTO THE 7-BIT
*       ASCII CONVERSION TABLE WHICH IS INITIALIZED FOR 
*       CDC 64-CHARACTER SET. 
* 
# 
 
      ITEM CHAR       U;     # DISPLAY CODE CHARACTER                  #
 
      $BEGIN
      XREF
        BEGIN 
        PROC NS$DBG;         # TRACE PROCEDURE CALL                    #
        END 
      $END
 
      ITEM I          U;     # WORD INDEX INTO CONVERSION TABLE        #
      ITEM J          U;     # BIT INDEX INTO CONVERSION TABLE WORD    #
# 
      DISPLAY CODE TO 7-BIT ASCII CHARACTER CONVERSION TABLE -
      INDEXABLE BY DISPLAY CODE AND INITIALIZED FOR CDC 64
      CHARACTER SET.
# 
      DEF L$ASCIITAB # 8 #;            # SIZE OF CONVERSION TABLE      #
      ARRAY ASCIITAB [0:7] S(1);
        BEGIN 
        ITEM ASCIIC7    U(00,00,60) = 
          [O"35203024161105432160", 
           O"44223124563115472360", 
           O"50243225165125532560", 
           O"54263323014262315500", 
           O"32554673416253265240", 
           O"27520512217240261340", 
           O"21667352250537205140", 
           O"23576743720134571660"];
        END 
CONTROL EJECT;
 
      $BEGIN
      NS$DBG("CDA");
      $END
 
      I = CHAR / L$ASCIITAB;           # WORD INDEX INTO ASCIITAB      #
      J = (CHAR - I*L$ASCIITAB) * 7;   # BIT INDEX INTO ASCIITAB WORD  #
      NS$CDA = B<J,7>ASCIIC7[I];       # RETURN ASCII CHARACTER        #
 
      RETURN; 
      END   # NS$CDA #
      TERM