BASIC-16A

* NAME: BASIC-16A DOC 70181826000 REV A PAGE 29

0951 * COMMAND INPUT DISCRIMINATOR 0952 * 0953 * 0954 * THIS ROUTINE WILL OUTPUT A QUESTION MARK AND 0955 * THEN INPUT A USER RESPONSE LINE. DEPENDING ON THE 0956 * USERS INPUT, THE FOLLOWING ACTION WILL BE TAKEN: 0957 * 0958 * 1) IF A LINE NUMBER STARTS THE INPUT LINE, 0959 * CONTROL WILL BE PASSED TO THE SOURCE TEXT EDITOR. 0960 * 0961 * 2) IF THE INPUT IS A SYSTEM COMMAND, CONTROL 0962 * WILL BE PASSED TO THE APPROPRIATE PROCESSING ROUTINE. 0963 * 0964 * 3) IF NONE OF THE ABOVE IT WILL BE EXECUTED 0965 * AS AN IMMEADIATE MODE STATEMENT. 0966 * 0967 * 0968 ORG '1000 MAIN BODY OF PROGRAM STARTS HERE 0969 * 0971 01000 0 10 00000 CMOD JST INIT FIRST TIME INITIALIZATION 0972 * 0973 * THE PREVIOUS INSTRUCTION WILL RE REPLACED WITH 0974 * A 'CRA' BY THE INITIALIZATION ROUTINE 0975 * 0982 01001 0 04 00034 STA SIP SET SIP TO INDICATE A COMMAND LINE 0983 01002 0 02 00045 LDA CPOS IF NOT AT START OF ASR LINE, 0984 01003 100040 SZE OUTPUT CARRIAGE RETURN, LINE FEED 0985 01004 0 10 00000 JST LFCR X 0986 01005 0 02 00425 LDA C277 REQUEST USER INPUT 0987 01006 0 10 01504 JST ILIN X 0989 01007 0 000220 SSBP DAC SBUF+SBUF BYTE POINTER TO SYSTEM INPUT BUFFER 0993 01010 0 02 01007 LDA SSBP SET POINTER TO FIRST CHARACTER OF 0997 01011 0 04 00037 STA SBP THE INPUT BUFFER 0998 01012 140040 CRA RESET THE PROGRAM BREAK FLAG 0999 01013 0 04 00103 STA BRKF X 1000 01014 0 10 03054 JST XCHR EXAMINE FIRST INPUT ITEM 1001 01015 0 11 00455 CAS INTF TEST FOR LINE NUMBER 1002 01016 100000 SKP NO 1003 01017 0 01 01313 JMP STMT YES ... GO TO TEXT EDITOR 1004 01020 0 04 00105 STA LODF NO ... RESET LOAD MODE FLAG 1005 01021 0 11 00456 CAS RELF DOES LINE START WITH A REAL CONSTANT? 1006 01022 100000 SKP X 1007 01023 0 01 04572 JMP ISN1 YES ... REPORT STATEMENT NUMBER ERROR 1008 01024 0 10 03173 JST DLCK NULL LINE ? 1009 01025 100000 SKP NO 1010 01026 0 01 01000 JMP CMOD YES ... GET ANOTHER INPUT LINE 1011 01027 0 11 00436 CAS C43 TEST FOR SYSTEM COMMAND 1012 01030 0 11 00441 CAS C54 X 1013 01031 0 01 03213 JMP ESMT NO....EXECUTE IMMEADIATE COMMAND 1014 01032 0 01 03213 JMP ESMT NO....EXECUTE IMMEADIATE COMMAND