A student writes (in all caps, no less): DR. PATT SORRY BUT I WAS UNCLEAR ABOUT PROGRAM 3. IT SAYS THAT THERE MUST BE A 20 CHARACTER CONSTRAINT ON THE MESSAGE. DOES THAT MEAN YOU WANT US TO KEEP A COUNTER FOR 20 AS WELL AS THE SENTINEL FOR ENTER. That would be best. Or we can assume, if you like, that people will not type in more than 20 characters. So, to make life easier, we will be changing the buffer sizes to 21 locations, so you can store the as well, making the counter (or other means) unnecessary. The revised programming assignment statement should be up later today. ALSO IS THE ASCII CODE FOR ENTER x0A. Yes. SINCE I DON'T WANT TO SEND YOU AN E-MAIL WITH ONLY EXTREMELY STUPID QUESTIONS I'LL ASK A SLIGHTLY LESS STUPID QUESTION. HOW DO WE KEEP THE ASSEMBLER FROM CONFUSING LABELS WITH NUMBERS. FOR EXAMPLE HOW DOES THE ASSEMBLER KNOW THAT WHEN I ASK IT TO LOAD XABCD AM I ASKING IT TO LOAD THE CONTENTS OF LOCATION LABELLED XABCD OR TO LOAD THE CONTENTS OF LOCATION HEX ABCD, IF BOTH EXIST. We do not allow both to exist. So, anything that can be confused with something else in assembly language can not be a label. For example, we can not label a location LDI. ...or TRAP. ...or R1. ALSO CAN WE USE NUMBERS IN A LABEL AND ARE LABELS OR ANY OTHER DATA CASE SENSITIVE. Yes, numbers, although as I recall, when I specified what a label can and can not be, we required the first character to not be a digit. Yes, labels are case sensitive. AGAIN is a different from again. THANK YOU You are welcome. ps. While I am at it, a couple of students seem to need more locations for their program, i.e., their program is running into the buffer space (x3100 and beyond). It shouldn't but for many it will. So, we are freeing up some space by changing the prompts as follows: Prompt 1: (E)ncrypt/(D)ecrypt: Prompt 2: Encryption Key: Prompt 3: Input Message: This takes up 55 locations in memory, instead of almost 200 locations. So, there should be plenty of space before you hit x3100. Good luck finishing PA 3. I am out of here. Be back Sunday night very late. Yale Patt