*DECK S$SJCR
          IDENT  S$SJCR 
          COMMENT  SET CONTROL REGISTER 
          SPACE  5
*     S$SJCR-   SET CONTROL REGISTER
* 
*     CALLING SEQUENCE- 
*         S$SJCR(RX,VALUE)
*     GIVEN-
*         RX = NUMBER OF R REGISTER TO BE SET 
*         VALUE = VALUE TO PUT IN R REGISTER
*         ASSUMING THAT RX = 1, 2 OR 3. 
*     DOES- 
*         USES SYSTEM TEXT PSSTEXT FOR ITS ASSEMBLY 
*         GETS CURRENT VALUES OF EF, R1, R2, AND R3 
*         UPDATES REGISTER RX 
          SPACE  3
          ENTRY  S$SJCR 
 S$SJCR   SUBR
          SX6    A1 
          SA6    SAVEA1 
          IFNOS 
  
          GETJCI ADDR 
  
          ELSE
          MX6    0
          SA6    ADDR              ZERO COMPLETION BIT FOR NOS/BE 
          GETJCI ADDR 
  
          ENDIF 
          SA1    SAVEA1 
          SA1    X1           RESTORE A1    X1 = ADDRESS OF RX
          SA4    X1           X4 = VALUE OF RX
          SA2    X4+SHIFTS-1
          SB2    X2           WORD INDEX   0 OR 1 
          AX2    18 
          SB3    X2           SHIFT FOR MASK AND NEW VALUE
          AX2    18 
          SA3    A1+1 
          SA3    X3           X3 = NEW VALUE
          SA4    B2+ADDR
          LX2    B3,X2           REPOSITION MASK
          LX0    B3,X3        REPOSTION NEW VALUE 
          BX1    -X2*X4       REMOVE OLD VALUE
          BX6    X1+X0        ADD NEW VALUE 
          SA6    A4 
          IFNOS 
  
          SETJCI ADDR 
  
          ELSE
  
          SA1    ADDR 
          MX0    -1 
          BX6    X1*X0             ZERO COMPLETION BIT FOR NOS/BE 
          SA6    A1                PUT THE DATA BACK
  
          SETJCI ADDR 
  
          ENDIF 
          EQ     S$SJCR 
* 
 ADDR     BSSZ   1
          BSS    1
* 
 SAVEA1   BSS    1
 SHIFTS   BSS    0
* 
*         VFD    24/MASK,18/SHIFT,18/WORD INDEX 
* 
          VFD    24/777777B,18/0,18/1      R1 REGISTER
          VFD    24/777777B,18/18,18/1     R2 REGISTER
          VFD    24/777777B,18/36,18/1     R3 REGISTER
          VFD    24/777777B,18/36,18/0     R1G REGISTER 
          VFD    24/77B,18/54,18/1         EF  FLAG 
          VFD    24/77B,18/54,18/0         EFG FLAG 
* 
          END 
