Question

Assembly (MARIE), how can I output my input variables on exit?

I am trying to compose an assembly (MARIE) program to output my input variables **on exit**. I am triggering an exit when . (period) is entered. I am transforming the input, and to later display the new value on exit.

Some context, FOO will return SBB when ran through Rot-13

However, my program is displaying the output on each iteration of my loop. I am instead wanting to not display anything, until . is entered and the program exits.

To further explain the current behavior and desired behavior, please entertain the following...

Current Behavior

- in F out S

- in O out B

- in O out B

- in . exits...

Desired Behavior

- in F *no output*

- in O *no output*

- in O *no output*

- in . out SBB, exits...

Here is my attempt thus far. It's my suspicion that I am calling output at the wrong time, but am unsure.

ORG     100  / Start the program at location 100 hexadecimal

/ Input

Load     Start  / Initialize character pointer to start of block

Store     Ptr

/ Program

Loop, Input / Take the input value

subt ChPe / subtract '.'(2E)

Skipcond 800 / AC will be 00, if the input is '.'

Jump Exit / if AC=0, exit the loop

Add ChPe / otherwise, add (2E) back to the difference

Store InVal / Store input value to be transformed into InVal

Jns ROT13 / Call the ROT13 subroutine

output

Jump Loop / repeat loop

Exit, Halt

/ Rotate-13 subroutine

ROT13, HEX 0

Load InVal / Get character

Add Val13 / Add 13

Store Hold / Save it in Hold

Subt ChZ / Check if modulo adjust is needed (past 'Z')

Skipcond 800 / No adjust needed if past 'Z'

Jump NoAdj / go to NoAdj

Add ChA / Add 'A' back to difference to perform modulo

subt One / subtract 1

Jump Done / Result is in AC

NoAdj, Load Hold / No adjust needed, get result

Done, JumpI ROT13 / Return result in AC

/ Constants

ChA,  HEX     0041 / Constant value 'A' for modulo adjust in subroutine

ChZ,  HEX     005A / Constant value 'Z' for modulo check in subroutine

ChPe,  HEX     2E / Constant period character that marks end of input

Val13,  DEC     13 / Constant rotate value of 13 for subroutine

One,  HEX     1 / Constant value 1

Start,  HEX     200 / Constant address for start of character block

/ Data

InVal,  HEX     0 / Reserved for subroutine input value

Hold,  HEX     0 / Reserved for temporary variable for subroutine

Ptr,  HEX     0 / Reserved for character pointer