Tutorial Work

1

Symbol	Memory Location (Hex)
S2	$103$
S1	$106$
A	$108$
One	$109$

MARIE instructions: (Hexadecimal)

HEX 1108 / Load A
HEX 3109 / Add One
HEX 9106 / Jump S1
HEX 3109 / Add One
HEX 2108 / Store A
HEX 7000 / Halt
HEX 3108 / Add A
HEX 9103 / Jump S2
HEX 0023 / A
HEX 0001 / One

title: Correct answer.

2

1. Jump 00B
2. Add 009

title: Correct answer.

3

/ Tutorial Exercise 3
 
       Load X        / Load given X
 
       Subt One      / Prepare the X > 1 statement
       Skipcond 800  / Interpret it as (X - 1) > 0 for truthy outcome
 
       Jump EndIf    / If X > 1 then:
       Load X        / Y = X + X
       Add X
       Store Y
       Clear         / X = 0
       Store X
 
EndIf, Load Y        / Y = Y + 1
	   Add One
       Store Y
	   Halt
 
X,     DEC 2
Y,     DEC 8
One,   DEC 1

title: Correct answer.

4

/ Tutorial Exercise 4
 
	 / C = C + D
	 Load C
     Add D
     Store C
 
	 / A = (A + B) - C
	 Load A
     Add B
     Subt C
     Store Sum
     Halt
 
A,   DEC 4
B,   DEC 3
C,   DEC 2
D,   DEC 1
Sum, DEC 0

$7$ memory accesses.

title: Correct answer.

/ TE 4 Optimised
 
	Load A
	Add B
	Subt C
	Subt D
	Store Sum
	Halt
	
A,   DEC 4
B,   DEC 3
C,   DEC 2
D,   DEC 1
Sum, DEC 0	

This is $5$ memory accesses.

5

Step	RTL	PC	IR	MAR	MBR	AC
Fetch	$MAR\leftarrow PC$	$0000$	$0000$	$0000$	$0000$	$0000$
	$MBR\leftarrow M[MAR]$	$0000$	$0000$	$0000$	$9100$	$0000$
	$IR\leftarrow MBR$	$0000$	$9100$	$0000$	$9100$	$0000$
	$PC\leftarrow PC+1$	$0001$	$9100$	$0000$	$9100$	$0000$
Decode	$MAR\leftarrow IR[11-0]$	$0001$	$9100$	$0100$	$9100$	$0000$
Execute	$PC\leftarrow IR[11-0]$	$0100$	$9100$	$0100$	$9100$	$0000$
Fetch	$MAR\leftarrow PC$	$0100$	$9100$	$0100$	$9100$	$0000$
	$MBR\leftarrow M[MAR]$	$0100$	$9100$	$0100$	$1106$	$0000$
	$IR\leftarrow MBR$	$0100$	$1106$	$0100$	$1106$	$0000$
	$PC\leftarrow PC+1$	$0101$	$1106$	$0100$	$1106$	$0000$
Decode	$MAR\leftarrow IR[11-0]$	$0101$	$1106$	$0106$	$1106$	$0000$
Execute	$MBR\leftarrow M[MAR]$	$0101$	$1106$	$0106$	$0001$	$0000$
	$AC\leftarrow MBR$	$0101$	$1106$	$0106$	$0001$	$0001$
Fetch	$MAR\leftarrow PC$	$0101$	$1106$	$0101$	$0001$	$0001$
	$MBR\leftarrow M[MAR]$	$0101$	$1106$	$0101$	$0103$	$0001$
	$IR\leftarrow MBR$	$0101$	$0103$	$0101$	$0103$	$0001$
	$PC\leftarrow PC+1$	$0102$	$0103$	$0101$	$0103$	$0001$
Decode	$MAR\leftarrow IR[11-0]$	$0102$	$0103$	$0103$	$0103$	$0001$
Execute	$MBR\leftarrow M[MAR]$	$0102$	$0103$	$0103$	$0000$	$0001$
	$MBR\leftarrow PC$	$0102$	$0103$	$0103$	$0102$	$0001$
	$M[MAR]\leftarrow MBR$	$0102$	$0103$	$0103$	$0102$	$0001$
	$MBR\leftarrow IR[11-0]$	$0102$	$0103$	$0103$	$0103$	$0001$
	$AC\leftarrow 1$	$0102$	$0103$	$0103$	$0103$	$0001$
	$AC\leftarrow AC+MBR$	$0102$	$0103$	$0103$	$0103$	$0104$
	$PC\leftarrow AC$	$0104$	$0103$	$0103$	$0103$	$0104$
Fetch	$MAR\leftarrow PC$	$0104$	$0103$	$0104$	$0103$	$0104$
	$MBR\leftarrow M[MAR]$	$0104$	$0103$	$0104$	$3106$	$0104$
	$IR\leftarrow MBR$	$0104$	$3106$	$0104$	$3106$	$0104$
	$PC\leftarrow PC+1$	$0105$	$3106$	$0104$	$3106$	$0104$
Decode	$MAR\leftarrow IR[11-0]$	$0105$	$3106$	$0106$	$3106$	$0104$
Execute	$MBR\leftarrow M[MAR]$	$0105$	$3106$	$0106$	$0001$	$0104$
	$AC\leftarrow AC+MBR$	$0105$	$3106$	$0106$	$0001$	$0105$
Fetch	$MAR\leftarrow PC$	$0105$	$3106$	$0105$	$0001$	$0105$
	$MBR\leftarrow M[MAR]$	$0105$	$3106$	$0105$	$c103$	$0105$
	$IR\leftarrow MBR$	$0105$	$c103$	$0105$	$c103$	$0105$
	$PC\leftarrow PC+1$	$0106$	$c103$	$0105$	$c103$	$0105$
Decode	$MAR\leftarrow IR[11-0]$	$0106$	$c103$	$0103$	$c103$	$0105$
Execute	$MBR\leftarrow M[MAR]$	$0106$	$c103$	$0103$	$0102$	$0105$
	$PC\leftarrow MBR$	$0102$	$c103$	$0103$	$0102$	$0105$
Fetch	$MAR\leftarrow PC$	$0102$	$c103$	$0102$	$0102$	$0105$
	$MBR\leftarrow M[MAR]$	$0102$	$c103$	$0102$	$7000$	$0105$
	$IR\leftarrow MBR$	$0102$	$7000$	$0102$	$7000$	$0105$
	$PC\leftarrow PC+1$	$0103$	$7000$	$0102$	$7000$	$0105$
Decode	$MAR\leftarrow IR[11-0]$	$0103$	$7000$	$0000$	$7000$	$0105$

title: Correct answer(?)