PRESS 1,6. (IF YOU GET BORED, YOU CAN GO THE OTHER WAY BY 1,7) (ESCAPE BY RESET). THE MONITOR SCANS THROUGH ALL MEMORY SUCCESSIVELY SHOWING ITS CONTENTS (DATA). WHERE THERE IS NO MEMORY AT ALL YOU WILL PROBABLY SEE THE FIRST TWO ADDRESS I LLI DC DC 8 LU QC Q Q DC O CO CO LU DC Q Q O i EX O CO LU DC Q DIGITS. DC O Q DC O I > DC 2.3 AT LAST, A PROGRAM 2.3.1 ASSEMBLY LANGUAGE, MACHINE LANGUAGE, THE INSTRUCTIONS lilt I8l| DC q LU - I Q_ _ l O D D ^ D CJ CJ LOAD, STORE AND JUMP A PROGRAM IS THE NAME FOR A SET OF STORED COMMANDS THAT THE MICROPROCESSOR WILL EXECUTE.
THESE ARE STORED IN BINARY, SINCE THAT'S ALL THAT ANYTHING CAN BE STORED IN, (ENTERED BY YOU IN HEX) AND ARE INDISTINGUISHABLE FROM ANYTHING ELSE. IF IT GETS THE CHANCETHE/xP (MICROPROCESSOR) WILL BUSY ITSELF TREATING D CJ 3 UO 0- Z O LLJ I I I JUI u u o o Q_ Q_ Q_ Q. Q- r-i n t t t t t - L , I . CO CO CO CO CO INFORMATION WHICH YOU MEANT AS DATA AS A PROGRAM. IT PROBABLY WONT BE DOING ANYTHING INTELLIGENT AND Wl LL HAVE TO BE o SUMMONED BACK WITH THE RESET KEY. SOME SORT OF TRANSLATION BETWEEN THE STORED BINARY/HEX AND YOU IS NEEDED. 10101101 2 MEANS A GREAT DEAL TO THE/xP BUT LITTLE TO YOU.
IT ACTUALLY MEANS "LOAD THE ACCUMULATOR WITH THE CONTENTS OF THE MEMORY ADDRESS DC co Illll SSSSQ 00 t 1 1 I + + I CO CO CO CO CO t t t t t x , x w LEAST SIGNIFICANT ADDRESS". THIS ISA LITTLE LONG FOR WRITING STRAIGHT INTO A PROGRAM AND IS USUALLY ABBREVIATED TO LDAABS, OR JUST LDA.ABSOLUTE MEANS ANYWHERE IN THE 64K. THE 6502 CAN ADDRESS 64K OF MEMORY WHICH IS DIVIDED INTO PAGES 256 BYTES LONG THE FIRST PAGE IS CALLED ZERO PAGE. LOCATIONS IN ZERO PAGE CAN DEFINED BY THE FOLLOWING TWO BYTES, OF WHICH THE FIRST IS THE + + + + + t t t t t t cococococo - CN(N(NCN CM CM CM CM CN CN BE ADDRESSED BY JUST ONE BYTE. THERE ARE SPECIAL INSTRUCTIONS TO DO THIS.
AT THE END OF THE MANUAL THERE ISA LIST OF ALL THESE MNEMONICS WITH THEIR HEX EQUIVALENTS IN APPENDIX B. SO IF WE WROTE THE PROGRAM IN MNEMOMICS ITW0ULD LOOK LIKE. Qi OO C D ^ O O O O C D ^ D Q U O I U U ^ CO 00 CD 00 O) O) u N ru ru rvi ru C J O - > Z Z Z Z Z MJ - I z u ru u ru ru ru ru rtJ ru ru z z z z z z LDAFE00 AND WE WOULD TRANSLATE IT FOR THE JUP AS THE THREE BYTES DO AD LOAD ABSOLUTE 00 LOWER BYTE OF ADDRESS FE HIGH BYTE OF ADDRESS WHICH WOULD CAUSE THE JUP TO PUT A0 (THE DATASTORED IN FE00) IN ITS ACCUMULATOR (REMEMBER USING THE MONITOR TO LOOK AT FE00?). THE TRANSLATION PROCESS IS CALLED ASSEMBLING AND COMPUTER PROGRAMS WHICH DO IT ARE CALLED ASSEMBLERS.
A RESIDENT ASSEMBLER IS ONE THAT RUNS (OPERATES) ON THE SAME MACHINE THAT IT ASSEMBLES FOR; A CROSS ASSEMBLER RUNS ON A DIFFERENT MACHINE. THE MNEMONICS CO CO CO t I- O DC CO D CO LU CO 8 I D DC DC LU 2 zo f- co DC o H co DC o CO CO LU CJ o > X W o o o o o h l h h co X X > DC DC DC DC DC DC CO I o o DC O DC LU (J O DC LL LU DC DC LL z DC D LU DC LU LJJ LU LU LU LL LL LL LL LL CO CO CO CO CO z z z z z DC DC DC DC DC hhhhh LLJ DC CO DCDCDCOCcCDCDCCCCJ LJJLULULuSSSSo _ J _ I _ J _ I ± ± ± ± O CJCJCJCJCOGOCOCO-I - co co -J - i LU 5 DC D LDA, STA etc ARE OFTEN CALLED ASSEMBLY LANGUAGE, THE GENERATED BINARY IS CALLED MACHINE CODE.
WE CAN LOAD THE ACCUMULATOR IN TEN OTHER WAYS; HERE ARE TWO OF THEM. Z O_ Q_ O_ O_ O DC DC LT CO U U U U Q Q ± - - l ZQ.Q.Q.Q. U Q _ > X > -J DC _ O O I- CO H DC J l J J L U L U DC DC DC