Wed, 23 Oct 2019, 01:22 final exam, .BLKW #1, and HALT

My students,

The Registrar has now committed the date of our final exam: December 13,
7pm to 10pm.  If you have been waiting for this to make plans for leaving
Austin, as far as EE306 is concerned, you can leave any time after 10pm
on December 13.

While I am writing this, I wanted to clear up a couple of points from class
yesterday:

1. A student asked about using HALT instead of TRAP x25 as the assembly 
language instruction that asks the operating system to halt the computer.
The answer is yes.  The assembler will recognize both HALT and TRAP x25
and for both will produce the LC-3 instruction: 1111 0000 00100101.

The assembler will also produce 1111 0000 00100011 for IN and TRAP x23,
and 1111 0000 00100001 for OUT and TRAP x21.

Table A.3 lists all the trap vectors the LC-3 currently supports, and 
the assembly language statement that can be used instead of TRAP.  Some
of them we have not talked about yet.  We will get to them before the end
of the semester.

2. A student caught me being sloppy by writing ".BLKW 1" and asked if we 
did not need to identify the "1" as hex, decimal, or binary.  He was right 
and I was wrong.  We do need to identify what the "1" is.  I personally
favor decimal in this case, although you are free to use hex or binary if
you prefer.  So, I should have written: .BLKW #1.

See you in class.


Yale Patt