Machine Code and Assembly Code.
Machine code can be used on two websites these are:
http://robowriter.info/little-man-computer/bo
http://peterhigginson.co.uk/LMC/
Some LMC instructions on agbonline.co.uk are:
Instruction |
Mnemonic |
MachineCode |
Load |
LDA |
5xx |
Store |
STA |
3xx |
Add |
ADD |
1xx |
Subtract |
SUB |
2xx |
Input |
INP |
901 |
Output |
OUT |
902 |
End |
HLT |
000 |
Branch if zero |
BRZ |
7xx |
Branch if zero or positive |
BRP |
8xx |
Branch always |
BRA |
6xx |
Data storage |
DAT |
|
agbonline.co.uk
Basic Hello World Example
A Basic 2 number addition calculator.
Machine Code |
Instructions |
Line Number |
Instruction |
901 |
In |
00 |
INP |
399 |
Sto 99 |
01 |
STA 99 |
901 |
In |
02 |
INP |
199 |
In |
03 |
ADD 99 |
902 |
Out |
04 |
OUT |
000 |
Cob |
05 |
HLT |
|
|
|
|
Input 3 numbers.
901 |
In |
315 |
Sto 15 |
901 |
In |
115 |
Add 15 |
316 |
Sto 15 |
901 |
In |
116 |
Add 16 |
318 |
Sto 18 |
902 |
Out |
000 |
Cob |
|
|
Input 3 numbers and subtract 2 numbers.
Location of instruction. |
Instruction in location. |
Instruction. |
0 |
901 |
In |
1 |
315 |
Sto 15 |
2 |
901 |
In |
3 |
316 |
Sto 16 |
4 |
901 |
In |
5 |
317 |
Sto 17 |
6 |
901 |
In |
7 |
318 |
Sto 18 |
8 |
901 |
In |
9 |
319 |
Sto 19 |
10 |
515 |
Lda 15 |
11 |
116 |
Add 16 |
12 |
117 |
Add 17 |
13 |
218 |
Sub 18 |
14 |
219 |
Sub 19 |
15 |
902 |
Out |
16 |
000 |
Cob |
http://robowriter.info/little-man-computer/bo
http://peterhigginson.co.uk/LMC/
In Peter higginsons LMC the code is slightly different but does the same thing.
Inp
Sta 15
Inp
Sta 16
Inp
Sta 17
Inp
Sta 18
Inp
Sto 19
Lda 15
Add 16
Add 17
Sub 18
Sub 19
Out
hlt
You can also do loops in Assembly Language using Little Man Computers.
To do:
Value= INPUT
Do while value >=0
print value
value -
next
end.
Can be represented in LMC as:
IN
STA 25
SUB ONE
BRZ 05
BRA 00
OUT
HLT
ONE DAT 01
Extension activity.
00 In
01 Sta a
02 In
03 Sta b
04 Lda b
05 Brz end
06 Sub one
07 Sta b
08 Lda count
09 Add a
10 Sta count
11 Bra start
12 Lda count
13 out
14 Hlt
15 Dat 01
16 Dat 02
17 Dat 03
18 Dat 04
Fibonacci Code
Add the previous two numbers together.
1 1 2 3 5 8 13 21 34 55 89 144
Teaching Ideas.
Show a Powerpoint having some fun identifying terms like Date a Bus = Databus.
Work through examples with
http://robowriter.info/little-man-computer/bo
http://peterhigginson.co.uk/LMC/
Research project on Important figures in history of computing.
Von Neumann
Babbage
IBM creator Hermann Hollerich
Alan Turing.
