Top 10k strings from Computer Studies - Logic (1984)(Longman Software).z80 in <root> / bin / z80 / software / Sinclair Spectrum Collection TOSEC.exe / Sinclair ZX Spectrum - Utilities & Educational / Sinclair ZX Spectrum - Utilities & Educational - [Z80] (TOSEC-v2007-01-01) /
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2 ~? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 2 ? ? ? ? ? ? ? ? ? ? ? ? ? 2 >@>@>@>@>@>@>@>@>@>@>@>@>@>@>@>@ 2 >@>@>@>@>@>@>@>@>@>@>@>@>@ 2 ;"1 0 0 1 1 0 1 0 2 Do you want to see this again? 2 !! EXCELLENT LOGIC !! 1 w$=z$+w$+z$: 1 w$=z$+w$+" 1 w$=z$+W$+z$ 1 w$=z$+" To calculate the total value of a BYTE, add together the decimal values of each BIT that is set to ""1""."+z$ 1 w$=z$+" In an 8 BIT computer like the Spectrum, every BYTE has 8 BITS - 8 Binary digiITS. 1 w$=z$+" Every BIT set to ""1"" has a decimal value. This value is 2 to the power of the BIT number." 1 w$=w$+" This testing is done through LOGIC GATES."+z$ 1 w$=w$+" It is called a Truth Table because in computer logic a bit set to ""1"" is TRUE. A bit set to ""0"" is FALSE."+z$ 1 w$=w$+" Every BIT has a reference number. The BIT NUMBERS run from Right to Left and are numbered 0 to 7."+z$ 1 w$=w$+" BIT 1 is worth 2^1 = 2. BIT 4 is worth 2^4 = 16."+z$ 1 W$=Z$+" The results can be classified in a TRUTH TABLE. Different GATES give different values (0 or 1) in the C column." 1 W$=Z$+" Computers process numbers by testing the logical relations between the BITS ." 1 LOGICAL BITS 1 Decimal value 1 C$="A LITTLE MORE REVISION IS NEEDED" 1 C$=" EVERYONE RIGHT EXCEPT THE LAST " 1 C$=" MADE IT BUT WITH "+ 1 BYTE total 1 BINARY BITS 1 B$="00011011" 1 AND OR NANDNOR X-ORf 1 A$=" LOGIC ": 1 ;Z$;Z$;Z$;Z$;Z$; 1 ;"A B C"; 1 ;"128 + 16+8 +2" 1 ;"1 1 0 0 1 0 0 1 1 ;"1 1 0 0 0 1 1 0" 1 ;"1 0 1 0 1 0 1 0"; 1 00011011Wr 1 -n)="1");c$(8 1 -SC)+" MISTAKES. " 1 )+MX,H(M,4 1 '" You start with 8 separate BITS"'" at 4 Logic gates. The outputs"'" from those gates are fed into"'" 2 more, and on to a final gate." 1 '" Would you like me to correct"'" any mistakes as you make them,"'" or would you prefer to plough"'" on to the end before I tell you"'" how you have done?" 1 '" Work your way through the gates"'" giving the outputs as you go." 1 '" This section will test your"'" understanding of LOGIC GATES,"'" and your logical reasoning." 1 "X-OR","0","1","1","0" 1 "X-OR is Exclusive OR . Either A or B but NOT both." 1 "The BIT in C is ""1"" if EITHER A OR B ( OR BOTH ) are ""1"". " 1 "The BIT in C is ""1"" ONLY if both A and B are ""1"" (TRUE)." 1 "Only BITS 0 and 4 are set to ""1"" by the NOR gate." 1 "Only BITS 0 & 4 satisfy NOT (A OR B) ." 1 "OR","0","1","1","1" 1 "NOR","1","0","0","0" 1 "NOR is ""NOT OR"" - the inverse of OR." 1 "NAND","1","1","1","0" 1 "BITS 2,3,5 & 6 satisfy (A OR B) but not (A AND B)." 1 "BITS 2,3,5 & 6 are set to ""1""." 1 "BITS 1,2,3,5,6 & 7 satisfy (A OR B) ." 1 "BITS 1 and 7 satisfy (A AND B)." 1 "BITS 0,2,3,4,5 & 6 satisfy NOT (A AND B) ." 1 "AND","OR","NAND","NOR","X-OR" 1 "AND","0","0","0","1" 1 "11101110" 1 "01101100" 1 "00010001" 1 " NAND means NOT AND . It gives the inverse of an AND operation. The BIT in C is set to ""1"" unless both A and B are ""1"". " 1 " In this example, the AND gate has set BITS 1 and 7 to ""1""." 1 " Here BITS 1,2,3,5,6 & 7 have all been set to ""1"". " 1 " BITS 0,2,3,4,5 & 6 are set to ""1""." 1 to select 1 to go on 1 to Wait till the end 1 for next 1 for new Option 1 for instant feedback or 1 a number 1 a new Option 1 ^ ^ ^"; 1 Watch the BITS being processed by this gate."+z$ 1 TRUTH TABLE 1 THE ";T$;" GATE 1 STOP THE TAPE - PRESS ANY KEY 1 PROGRAM OPTIONS 1 PRODUCTS/CONTRACT BOOKS 1 I WILL SHOW YOU WHERE. 1 HOW'S YOUR LOGIC ? 1 END OF PROGRAM 1 DIFFERENT (T/F) 1 DIFFERENT (F/T) 1 BOTH 1 (TRUE) 1 BOTH 0 (FALSE) 1 BIT NUMBERS 1 Another go 1 1984 MERCURIAN PULP 1 - don't worry you have a 50% chance of error 1 The BYTE 1 HOW'S YOUR LOGIC? 1 END OF PROGRAM 1 BITS 2,3,5 & 6 satisfy (A OR B) but not (A AND B). 1 YOU MADE SOME MISTAKES. 1 LOGICAL GATES 1 LOGICAL BITS 1 BINARY BITS