.TITLE  CLK  -  SWITCH REGISTER CLOCK UTILITY
;----------------------------------------------------------------------;
;       MODULE:         CLK                                            ;
;       LANGUAGE:       DEC PDP-11/34 MACRO ASSEMBLY LANGUAGE (V3.2)   ;
;       SYSTEM:         DEC PDP-11/34 RUNNING UNDER RSX-11M V3.2       ;
;                       MOSTEK CORPORATION                             ;
;                       COMPUTER AIDS TO DESIGN DIVISION               ;
;                       1215 WEST CROSBY ROAD                          ;
;                       CARROLLTON, TEXAS  75006                       ;
;                       (214)  323-8813                                ;
;----------------------------------------------------------------------;
;       PROGRAMMER:     KEVIN KLUGHART                                 ;
;----------------------------------------------------------------------;
;       DATE:           09-04-81 @ 12:00 CDST                          ;
;----------------------------------------------------------------------;
;       PURPOSE:        THIS UTILITY SERVES AS A SWITCH REGISTER CLOCK ;
;                       BY DISPLAYING THE CURRENT SYSTEM TIME TO THE   ;
;                       SWITCH REGISTER AT PERIODIC INTERVALS.  THE    ;
;                       FORMAT FOR THE DISPLAY IS AS FOLLOWS:          ;
;                                                                      ;
;                              HH MM SS                                ;
;                                                                      ;
;                       WHERE THE HOUR, MINUTE, AND SECOND ARE OCTAL.  ;
;----------------------------------------------------------------------;
        .IDENT  /V01.00/        ; CURRENT RELEASE

        .SBTTL  EXTERNAL MACROS
;----------------------------------------------------------------------;
;                                                                      ;
;       EXTERNAL MACROS                                                ;
;                                                                      ;
;----------------------------------------------------------------------;
;       EXECUTIVE DIRECTIVE MACROS                                     ;
;----------------------------------------------------------------------;
        .MCALL   EXIT$S         ; EXIT TASK
        .MCALL   GTIM$S         ; GET TIME PARAMETERS
        .MCALL   MRKT$S         ; MARK TIME (DELAY)
        .MCALL   WTSE$S         ; WAIT ON SINGLE EVENT FLAG

        .SBTTL   DATA BUFFERS
;----------------------------------------------------------------------;
;                                                                      ;
;       DATA BUFFERS                                                   ;
;                                                                      ;
;----------------------------------------------------------------------;
;       DEFINE GET TIME PARAMETERS BUFFER                              ;
;----------------------------------------------------------------------;
        .EVEN
TIMBUF: .BLKW   10              ; DEFINE 8 WORD TIME BUFFER

        .SBTTL  CLK  -  MAIN SWITCH REGISTER CLOCK UTILITY
;----------------------------------------------------------------------;
;                                                                      ;
;       CLK  -  MAIN SWITCH REGISTER CLOCK UTILITY                     ;
;                                                                      ;
;----------------------------------------------------------------------;
;       START OF MAIN PROCESSING LOOP - GET CURRENT TIME               ;
;----------------------------------------------------------------------;
        .EVEN
START:  GTIM$S  #TIMBUF         ; GET CURRENT TIME PARAMETERS
        BCS     EXIT            ; ABORT UTILITY ON ERROR
;----------------------------------------------------------------------;
;       LOAD CURRENT HOUR                                              ;
;----------------------------------------------------------------------;
        CLR     R2              ; CLEAR SWITCH REGISTER TIME ACCUMULATOR
        MOV     #TIMBUF,R5      ; LOAD OFFSET ADDRESS FOR TIME BUFFER
        MOV     G.TIHR(R5),R0   ; GET CURRENT HOUR
        MOV     #14,R1          ; SHIFT HOUR 4 OCTAL DIGITS
        ADD     #-12.,R0        ; SUBTRACT OUT 12 HOURS (NOT MILITARY TIME)
        BGT     10$             ; IF > 0 THEN TIME IS CORRECT
        ADD     #12.,R0         ; IF <=0 THEN ADD BACK 12 HOURS

10$:    ASL     R0              ; SHIFT HOUR 1 BIT LEFT
        DEC     R1              ; DECREMENT SHIFT COUNT
        BNE     10$             ; AND SHIFT AGAIN IF NECESSARY

        BIS     R0,R2           ; AND SET BITS IN TIME ACCUMULATOR
;----------------------------------------------------------------------;
;       LOAD CURRENT MINUTE                                            ;
;----------------------------------------------------------------------;
        MOV     G.TIMI(R5),R0   ; GET CURRENT MINUTE
        MOV     #6,R1           ; SHIFT MINUTE 2 OCTAL DIGITS

20$:    ASL     R0              ; SHIFT MINUTE 1 BIT LEFT
        DEC     R1              ; DECREMENT SHIFT COUNT
        BNE     20$             ; AND SHIFT AGAIN IF NECESSARY

        BIS     R0,R2           ; AND SET BITS IN TIME ACCUMULATOR
;----------------------------------------------------------------------;
;       LOAD CURRENT SECOND                                            ;
;----------------------------------------------------------------------;
        BIS     G.TISC(R5),R2   ; GET CURRENT SECOND AND SET IN TIME ACCUMULATOR
;----------------------------------------------------------------------;
;       SET CURRENT TIME IN SWITCH REGISTER AND DELAY ONE SECOND       ;
;----------------------------------------------------------------------;
        MOV     R2,SWR          ; SET TIME IN SWITCH REGISTER

        MRKT$S  #1,#1,#2        ; DELAY ONE SECOND
        BCS     EXIT            ; ABORT EXECUTION ON ERROR

        WTSE$S  #1              ; WAIT FOR EVENT COMPLETION
        BCC     START           ; CONTINUE IF NO ERROR

        .SBTTL  TASK EXIT DUE TO FATAL DIRECTIVE EXECUTION ERROR
;----------------------------------------------------------------------;
;                                                                      ;
;       TASK EXIT DUE TO FATAL DIRECTIVE EXECUTION ERROR               ;
;                                                                      ;
;----------------------------------------------------------------------;
EXIT:   EXIT$S                  ; EXIT TASK
        .END    START           ; END OF MAIN PROGRAM