Listing of file='TUTE2.BAS;01' on disk='vmedia/asmtut_disk1-sector.ccvf'
100 REM BINARY LOGIC TUTE2 22/8/81 110 GOTO 200:REM 150 W/O MENU 120 Z= CALL (0):PLOT 3,0,31,11:RETURN 130 PLOT 3,62,31:POKE KB,0:Z= CALL (18) 131 IF PEEK (KB)= 0THEN 131 132 GOSUB 120:PRINT "/":GOTO 120 133 GOSUB 120:GOTO 120 134 PLOT 6,2,3,0,31:RETURN 140 FOR I= 1TO 1000:NEXT :RETURN 150 POKE 32941,191:POKE 32940,172:CLEAR 100:PLOT 27,4:PRINT "LOA SCROLL.PRG":PLOT 27,27 160 POKE 33283,173:POKE 33284,191 170 PLOT 6,2,15,12,27,24 200 KB= 33278:DU= 49113:POKE DU,255 210 PLOT 14,6,3,3,16,0:PRINT "TUTORIAL #2 - BINARY LOGIC":PLOT 6,2,15,3,0,25 220 PRINT "IN THIS TUTORIAL WE WILL LOOK BRIEFLY AT THE THEORETICAL" 230 PRINT "BASIS FOR THE SWITCHING CIRCUITS THAT, WHEN GROUPED TOGETHER," 240 PRINT "MAKE UP A MICROPROCESSOR.":GOSUB 134 250 FOR I= 20TO 12STEP - 2:Z= CALL (I):NEXT 260 Z= CALL (18):INPUT "THROUGHOUT, PRESS ENTER TO PROCEED. ";Z:PLOT 28,11:GOSUB 120 270 PRINT "DIGITAL COMPUTERS ARE BASICALLY A COLLECTION OF SWITCHES OR":GOSUB 120 280 PRINT "ELECTRONIC CIRCUITS CALLED GATES WHICH ARE EITHER OPEN OR CLOSED":GOSUB 130 290 PRINT "A UNIFIED SYSTEM OF CONNECTING THESE GATES HAS BEEN ADOPTED":GOSUB 120 300 PRINT "WHICH IS CALLED BOOLEAN ALGEBRA.":GOSUB 130 310 PRINT "THIS SYSTEM ALLOWS SIMPLE DECISION MAKING AND EVEN ARITHMETIC.":GOSUB 130 320 PRINT "THE BASIC ASSUMPTION IS THAT ALL STATEMENTS ARE EITHER":GOSUB 120 330 PRINT "TRUE (1) OR FALSE (0).":GOSUB 130 340 PRINT "THE BASIC OPERATORS IN THIS ALGEBRA ARE SHOWN ABOVE.":GOSUB 120 350 PLOT 3,0,2:PRINT "OPERATORS:":PLOT 6,3 360 PRINT "EQUALS":PRINT "AND":PRINT "OR":PRINT "NOT":GOSUB 134 370 PRINT "ALTHOUGH OTHERS ARE DERIVED FROM THEM SUCH AS:":GOSUB 120 380 PRINT "NAND, NOR, XOR.":GOSUB 130 390 PRINT "EQUALS AND NOT (EQUALS) ARE SELF EVIDENT FOR ANY TWO BITS:":GOSUB 133 400 PRINT "B = A B = NOT A":GOSUB 133 410 PRINT "A B A B":GOSUB 120 420 PRINT "0 0 0 1":GOSUB 120 430 PRINT "1 1 1 0":GOSUB 130 440 PRINT "SINCE BOOLEAN ALGEBRA HAS ONLY TWO NUMERICAL VALUES, 0 AND 1,":GOSUB 120 450 PRINT "ANY TWO BITS MAY ONLY OCCUR IN ONE OF FOUR COMBINATIONS:-":GOSUB 133 460 PRINT "0,0 OR 0,1 OR 1,0 OR 1,1":GOSUB 130 470 PLOT 3,16,3:PRINT "A OR B = ? A AND B = ?" 480 PLOT 6,6,3,16,5:PRINT "0 0 0 0 0 0" 490 PLOT 3,16,6:PRINT "0 1 1 0 1 0" 500 PLOT 3,16,7:PRINT "1 0 1 1 0 0" 510 PLOT 3,16,8:PRINT "1 1 1 1 1 1":GOSUB 134 520 PRINT "THE SIMPLE BUT FIXED RULES OF BOOLEAN ALGEBRA GIVE THE RESULTS":GOSUB 120 530 PRINT "OF USING AND OR OR ON THE FOUR POSSIBLE COMBINATIONS":GOSUB 120 540 PRINT "OF BITS AND THESE ARE REPRESENTED IN TRUTH TABLES.":GOSUB 120 550 PRINT "THESE ARE SHOWN ABOVE.":GOSUB 130 560 PRINT "REMEMBER THE CONVENTION THAT 1 = TRUE AND 0 = FALSE":GOSUB 120 570 PRINT "AND STUDY THESE TRUTH TABLES TO SEE HOW THEY ARE DERIVED.":GOSUB 130 580 PRINT "A FURTHER EXTENSION OF THESE OPERATORS IS THE EXCLUSIVE OR":GOSUB 120 590 PRINT "OPERATOR AND IT DIFFERS FROM OR IN THAT THE RESULT IS ONLY":GOSUB 120 600 PRINT "TRUE IF THE TWO QUANTITIES ARE DIFFERENT.":GOSUB 120 610 PLOT 3,0,10:PRINT "A XOR B = ?" 620 PLOT 6,6:PRINT "0 0 0" 630 PRINT "0 1 1" 640 PRINT "1 0 1" 650 PRINT "1 1 0":GOSUB 134 660 PRINT "THE TRUTH TABLE FOR XOR APPEARS ABOVE.":GOSUB 130 670 PRINT "A CIRCUIT WHOSE OUTPUT IS EXCLUSIVE OR MAY BE USED FOR EXAMPLE":GOSUB 120 680 PRINT "TO CHECK PARITY IN A SEQUENCE OF BYTES.":GOSUB 130 690 PRINT "PARITY IS A USEFUL ERROR CHECKING METHOD WHEREBY YOU APPEND":GOSUB 120 700 PRINT "AN EXTRA BIT TO EVERY GROUP OF BITS TO INDICATE WHETHER":GOSUB 120 710 PRINT "THE GROUP HAS AN ODD (1) OR EVEN (0) NUMBER OF 1'S.":GOSUB 130 720 PRINT "BY MONITORING FOR PARITY YOU MAY DETECT MOST ERRORS IN":GOSUB 120 730 PRINT "TRANSMISSION OF A GROUP OF BYTES.":GOSUB 120 740 PRINT "PARITY BITS ARE USUALLY ADDED TO EACH BYTE OR NIBBLE.":GOSUB 130 750 PRINT "AN EVEN MORE USEFUL APPLICATION FOR A CIRCUIT WHICH PRODUCES":GOSUB 120 760 PRINT "EXCLUSIVE OR OUTPUT IS AS AN ADDER.":GOSUB 130 770 PRINT "THE TRUTH TABLE FOR EXCLUSIVE OR IS ACTUALLY THE LEAST":GOSUB 120 780 PRINT "SIGNIFICANT DIGIT OF THE RESULT OF ADDING TWO BITS AND":GOSUB 120 790 PRINT "BY ADDING AN AND GATE IN PARALLEL YOU MAY GATHER THE MOST":GOSUB 120 800 PRINT "SIGNIFICANT DIGIT AT IT'S OUTPUT. REMEMBER THAT THE AND":GOSUB 120 810 PRINT "OPERATOR ONLY PRODUCES 1 IF BOTH INPUTS ARE 1 AND THAT THE":GOSUB 120 820 PRINT "ONLY TIME YOU GET CARRY IN BINARY BIT ADDITION IS WHEN":GOSUB 120 830 PRINT "BOTH BITS ARE 1!":GOSUB 130 840 PRINT "BINARY ADDITION WILL USUALLY INVOLVE UP TO THREE BITS THOUGH:":GOSUB 133 850 PRINT "FIRST BIT PLUS SECOND BIT PLUS MAYBE A CARRY.":GOSUB 130 860 PRINT "THIS REQUIRES TWO OF THE CIRCUITS JUST DESCRIBED PLUS AN":GOSUB 120 870 PRINT "OR GATE SUITABLY CONNECTED.":GOSUB 130 880 PRINT "BY EXTENDING THE COMBINATIONS OF THE VARIOUS GATES WHICH":GOSUB 120 890 PRINT "GIVE THEIR OUTPUTS AS AND, OR, NAND, NOR, EXCLUSIVE OR,":GOSUB 120 900 PRINT "YES, OR NOT WE MAY DESIGN CIRCUITS TO:-":GOSUB 133 910 PRINT "ADD A COUPLE OF BINARY DIGITS OR STRINGS OF THEM,":GOSUB 130 920 PRINT "DECODE BINARY STRINGS TO OTHER NUMBER SYSTEMS,":GOSUB 130 930 PRINT "ENCODE OTHER NUMBER SYSTEMS INTO BINARY,":GOSUB 130 940 PRINT "MULTIPLEX DATA BY SELECTING A SPECIFIC BIT FROM A STRING,":GOSUB 130 950 PRINT "DEMULTIPLEX DATA BY PLACING A SPECIFIC BIT ONTO ONE OF AN":GOSUB 120 960 PRINT "ASSORTMENT OF AVAILABLE OUTPUTS.":GOSUB 130 970 PRINT "YOUR MICROPROCESSOR IS ACTUALLY A COLLECTION OF SUCH CIRCUITS":GOSUB 120 980 PRINT "WHICH EMPLOY COMBINATIONAL LOGIC.":GOSUB 130 990 PRINT "A THOROUGH UNDERSTANDING OF THE EFFECTS OF BIT-WISE COMPARISON":GOSUB 120 1000 PRINT "OF DATA USING BOOLEAN OPERATORS WILL LEAD TO MORE EFFECTIVE":GOSUB 120 1010 PRINT "PROGRAMMING, PARTICULARLY IN ASSEMBLER, BUT ALSO IN BASIC.":GOSUB 130 1020 PRINT "IN THE NEXT TUTORIAL WE WILL LOOK AT THE 'SOFTWARE FACE' OF":GOSUB 120 1030 PRINT "THE 8080A MICROPROCESSOR WHICH IS USED IN THE CCII.":GOSUB 130 1040 PRINT "AS THE HARDWARE IS LARGELY FIXED IN THE CCII, WE WILL NOT":GOSUB 120 1050 PRINT "CONSIDER THOSE PARTS OF THE 8080A WHICH ARE MODIFIED":GOSUB 120 1060 PRINT "BY HARDWARE EXCEPT IN SO FAR AS THEY ARE ALREADY IMPLEMENTED":GOSUB 120 1070 PRINT "IN THE CCII.":GOSUB 130 1080 PRINT "USING ASSEMBLER HOWEVER ALLOWS YOU TO CARRY OUT ALMOST ANY":GOSUB 120 1090 PRINT "OPERATION OF WHICH THE 8080A IS CAPABLE UNLIKE BASIC WHICH":GOSUB 120 1100 PRINT "HAS IT'S FORMAT LARGELY FIXED.":GOSUB 130 1110 GOSUB 2010 1120 INPUT "BACK TO MENU, ON TO TUTORIAL 3, OR TERMINATE? ";YN$:GOSUB 2000:PLOT 12 1130 IF YN$= "B"THEN PLOT 1 1140 IF YN$= "3"THEN LOAD "TUTE3":RUN 1150 PLOT 27,11:END 2000 FOR I= 24TO 8STEP - 2:Z= CALL (I):NEXT 2010 FOR I= 8TO 24STEP 2:Z= CALL (I):NEXT :RETURN