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Execute Computer/Zero

From Rosetta Code
Task
Execute Computer/Zero
You are encouraged to solve this task according to the task description, using any language you may know.
Execute Computer/Zero is an implementation of Computer/zero Assembly. Other implementations of Computer/zero Assembly.
Task

Create a Computer/zero Assembly emulator. You may consider this webpage as a reference implementation. Output the results of the sample programs "2+2" and "7*8" found there.

  •   The virtual machine "bytecode" needs to be able to modify itself (or at least act as though it can) while the virtual machine is running, to be consistent with the reference implementation.
  •   For output, it is sufficient to have the implementation of the STP opcode return the accumulator to your actual language, and then use your standard printing routines to output it.
Bonus Points
Run all 5 sample programs at the aforementioned website and output their results.




ALGOL 68[edit]

BEGIN # execute some ComputerZero programs                                 #
# instructions #
INT nop = 0, lda = 1, sta = 2, add = 3, sub = 4, brz = 5, jmp = 6, stp = 7;
PROC instr = ( INT op, v )INT: ( 32 * op ) + v;
OP NOP = ( INT v )INT: instr( nop, v );
OP LDA = ( INT v )INT: instr( lda, v );
OP STA = ( INT v )INT: instr( sta, v );
OP ADD = ( INT v )INT: instr( add, v );
OP SUB = ( INT v )INT: instr( sub, v );
OP BRZ = ( INT v )INT: instr( brz, v );
OP JMP = ( INT v )INT: instr( jmp, v );
OP STP = ( INT v )INT: instr( stp, v );
# executes the program named name #
PROC execute = ( STRING name, []INT program )VOID:
BEGIN
[ 0 : 31 ]INT m; # the computer 32 has bytes of memory #
FOR i FROM LWB m TO UPB m DO m[ i ] := 0 OD;
# "assemble" the program #
INT m pos := -1;
FOR i FROM LWB program TO UPB program DO
m[ m pos +:= 1 ] := program[ i ]
OD;
# execute the program #
BOOL running := TRUE;
INT pc := 0;
INT a := 0;
WHILE running DO
INT op := m[ pc ] OVER 32;
INT operand := m[ pc ] MOD 32;
pc +:= 1 MODAB 32;
IF op = nop THEN SKIP
ELIF op = lda THEN a := m[ operand ]
ELIF op = sta THEN m[ operand ] := a
ELIF op = add THEN a +:= m[ operand ] MODAB 256
ELIF op = sub THEN a -:= m[ operand ] MODAB 256
ELIF op = brz THEN IF a = 0 THEN pc := operand FI
ELIF op = jmp THEN pc := operand
ELSE # stp #
running := FALSE;
print( ( " " * ( 12 - ( ( UPB name - LWB name ) + 1 ) ) ) );
print( ( name, ": ", whole( a, -3 ), newline ) )
FI
OD
END # execute # ;
# task test programs (from the Computer Zero website) #
# the unary NOP, LDA, STA, etc. operators are used to construct the #
# instructions; as parameterless operators aren't allowed, NOP and STP #
# must have a dummy parameter #
execute( "2+2", ( LDA 3, ADD 4, STP 0, 2, 2 )
);
execute( "7*8"
, ( LDA 12, ADD 10, STA 12, LDA 11, SUB 13, STA 11, BRZ 8, JMP 0
, LDA 12, STP 0, 8, 7, 0, 1
)
);
execute( "fibonacci"
, ( LDA 14, STA 15, ADD 13, STA 14, LDA 15, STA 13, LDA 16, SUB 17
, BRZ 11, STA 16, JMP 0, LDA 14, STP 0, 1, 1, 0
, 8, 1
)
);
execute( "linkedList"
, ( LDA 13, ADD 15, STA 5, ADD 16, STA 7, NOP 0, STA 14, NOP 0
, BRZ 11, STA 15, JMP 0, LDA 14, STP 0, LDA 0, 0, 28
, 1, 0, 0, 0, 6, 0, 2, 26
, 5, 20, 3, 30, 1, 22, 4, 24
)
);
execute( "prisoner"
, ( NOP 0, NOP 0, STP 0, 0, LDA 3, SUB 29, BRZ 18, LDA 3
, STA 29, BRZ 14, LDA 1, ADD 31, STA 1, JMP 2, LDA 0, ADD 31
, STA 0, JMP 2, LDA 3, STA 29, LDA 1, ADD 30, ADD 3, STA 1
, LDA 0, ADD 30, ADD 3, STA 0, JMP 2, 0, 1, 3
)
);
# subtractions yielding negative results #
execute( "0-255", ( LDA 3, SUB 4, STP 0, 0, 255 ) );
execute( "0-1", ( LDA 3, SUB 4, STP 0, 0, 1 ) );
# overflow on addition #
execute( "1+255", ( LDA 3, ADD 4, STP 0, 1, 255 ) )
END
 
Output:
         2+2:   4
         7*8:  56
   fibonacci:  55
  linkedList:   6
    prisoner:   0
       0-255:   1
         0-1: 255
       1+255:   0

Applesoft BASIC[edit]

 0  FOR P = 1 TO 5: READ S$: PRINT S$" : ";: FOR MEM = 0 TO 31: ON  LEN (S$) > 0 GOSUB 90:A =  VAL (S$): GOSUB 2: NEXT MEM: GOSUB 7: PRINT A: NEXT P: END 
1 LET A = V: RETURN
2 LET P$ = MID$ (P$,1,MEM) + CHR$ (A) + MID$ (P$,MEM + 2,31 - MEM): PRINT MID$ ("",1 ^ FRE (0));: RETURN
3 LET A = A + V:A = A - 256 * (A > 255): RETURN
4 LET A = A - V:A = A + 256 * (A < 0): RETURN
5 IF A > 0 THEN RETURN
6 LET PC = MEM: RETURN
7 LET PC = 0
8 LET A = 0
9 FOR OP = 0 TO 7 STEP 0
10 LET PC = PC + 1 - 32 * (PC = 32)
20 LET I = ASC ( MID$ (P$,PC,1))
30 LET OP = INT (I / 32)
40 LET MEM = I - OP * 32
50 LET V = ASC ( MID$ (P$,MEM + 1,1))
60 ON OP GOSUB 1,2,3,4,5,6
70 NEXT OP
80 RETURN
90 READ S$: RETURN
100 DATA "2+2",35,100,224,2,2,
200 DATA "7*8",44,106,76,43,141,75,168,192,44,224,8,7,0,1,
300 DATA "FIBONACCI",46,79,109,78,47,77,48,145,171,80,192,46,224,1,1,0,8,1,
400 DATA "LINKED LIST",45,111,69,112,71,0,78,0,171,79,192,46,224,32,0,28,1,0,0,0,6,0,2,26,5,20,3,30,1,22,4,24
500 DATA "PRISONER",0,0,224,0,0,35,157,178,35,93,174,33,127,65,194,32,127,64,192,35,93,33,126,99,

Forth[edit]

Works with: gforth version 0.7.3


#! /usr/bin/gforth
 
\ Execute Computer/Zero
 
\ reserve 32 cells for memory
 
CREATE MEMORY 32 cells allot
MEMORY 32 cells erase
 
 
\ gets the address of the memory cell with the given index
: mem ( ix - addr )
cells MEMORY +
;
 
\ splits a byte into instruction and argument
: instruction ( ix -> arg inst )
mem @ dup
32 mod swap
32 /
;
 
\ defines a program by giving its name and the 32 memory contents (in binary)
: PROGRAM ( "name" "b01" ... "b31" -- )
CREATE
base @ >r 2 base !
32 0 DO
BEGIN
parse-name
dup 0= WHILE
2drop refill drop
REPEAT
s>number? 2drop ,
LOOP
r> base !
DOES> ( -- n00 ... n31 )
32 0 DO
dup @ swap cell+
LOOP
drop
;
 
\ loads 32 bytes from the stack into memory
: >memory ( n00 ... n31 -- )
-1 31 -DO
i mem !
1 -LOOP
;
 
\ prints accumulator and program counter
: .acc-pc ( acc pc -- acc pc )
over 3 .r dup 3 .r
;
 
\ prints the argument
: .x ( x -- x )
dup 2 .r
;
 
\ performs one step of the simulation
: step ( acc pc -- acc' pc' )
.acc-pc ."  : "
tuck instruction CASE
0 OF ." NOP " .x drop swap 1+ ENDOF
1 OF ." LDA " .x nip mem @ swap 1+ ENDOF
2 OF ." STA " .x over swap mem ! swap 1+ ENDOF
3 OF ." ADD " .x mem @ + 256 mod swap 1+ ENDOF
4 OF ." SUB " .x mem @ - 256 mod swap 1+ ENDOF
5 OF ." BRZ " .x over 0= if rot drop else drop swap 1+ then ENDOF
6 OF ." JMP " .x rot drop ENDOF
7 OF ." STP " .x drop nip -1 ENDOF
ENDCASE
." -> " .acc-pc
;
 
\ runs the simulation, starting with accumulator zero and program counter zero
: run ( -- acc )
0 0 cr
BEGIN
dup 0>= WHILE
step cr
REPEAT
drop
;
 
 
\ the five example programs
 
PROGRAM 2+2
00100011 01100100
11100000 00000010
00000010 00000000
00000000 00000000
00000000 00000000
00000000 00000000
00000000 00000000
00000000 00000000
00000000 00000000
00000000 00000000
00000000 00000000
00000000 00000000
00000000 00000000
00000000 00000000
00000000 00000000
00000000 00000000
 
PROGRAM 7*8
00101100 01101010
01001100 00101011
10001101 01001011
10101000 11000000
00101100 11100000
00001000 00000111
00000000 00000001
00000000 00000000
00000000 00000000
00000000 00000000
00000000 00000000
00000000 00000000
00000000 00000000
00000000 00000000
00000000 00000000
00000000 00000000
 
PROGRAM Fibonacci
00101110 01001111
01101101 01001110
00101111 01001101
00110000 10010001
10101011 01010000
11000000 00101110
11100000 00000001
00000001 00000000
00001000 00000001
00000000 00000000
00000000 00000000
00000000 00000000
00000000 00000000
00000000 00000000
00000000 00000000
00000000 00000000
 
PROGRAM List'
00101101 01101111
01000101 01110000
01000111 00000000
01001110 00000000
10101011 01001111
11000000 00101110
11100000 00100000
00000000 00011100
00000001 00000000
00000000 00000000
00000110 00000000
00000010 00011010
00000101 00010100
00000011 00011110
00000001 00010110
00000100 00011000
 
PROGRAM Prisoner
00000000 00000000
11100000 00000000
00100011 10011101
10110010 00100011
01011101 10101110
00100001 01111111
01000001 11000010
00100000 01111111
01000000 11000010
00100011 01011101
00100001 01111110
01100011 01000001
00100000 01111110
01100011 01000000
11000010 00000000
00000001 00000011
 
 
\ runs a program and drops the result
: run-sample-program ( -- )
>memory run drop
;
 
 
\ run the five example programs
 
2+2 run-sample-program
7*8 run-sample-program
Fibonacci run-sample-program
List' run-sample-program
Prisoner run-sample-program
 
bye
 
Output:
 0  0 : LDA  3 ->   2  1
 2  1 : ADD  4 ->   4  2
 4  2 : STP  0 ->   4 -1
 0  0 : LDA 12 ->   0  1
 0  1 : ADD 10 ->   8  2
 8  2 : STA 12 ->   8  3
 8  3 : LDA 11 ->   7  4
 7  4 : SUB 13 ->   6  5
 6  5 : STA 11 ->   6  6
 6  6 : BRZ  8 ->   6  7
 6  7 : JMP  0 ->   6  0
 6  0 : LDA 12 ->   8  1
 8  1 : ADD 10 ->  16  2
16  2 : STA 12 ->  16  3
16  3 : LDA 11 ->   6  4
 6  4 : SUB 13 ->   5  5
 5  5 : STA 11 ->   5  6
 5  6 : BRZ  8 ->   5  7
 5  7 : JMP  0 ->   5  0
 5  0 : LDA 12 ->  16  1
16  1 : ADD 10 ->  24  2
24  2 : STA 12 ->  24  3
24  3 : LDA 11 ->   5  4
 5  4 : SUB 13 ->   4  5
 4  5 : STA 11 ->   4  6
 4  6 : BRZ  8 ->   4  7
 4  7 : JMP  0 ->   4  0
 4  0 : LDA 12 ->  24  1
24  1 : ADD 10 ->  32  2
32  2 : STA 12 ->  32  3
32  3 : LDA 11 ->   4  4
 4  4 : SUB 13 ->   3  5
 3  5 : STA 11 ->   3  6
 3  6 : BRZ  8 ->   3  7
 3  7 : JMP  0 ->   3  0
 3  0 : LDA 12 ->  32  1
32  1 : ADD 10 ->  40  2
40  2 : STA 12 ->  40  3
40  3 : LDA 11 ->   3  4
 3  4 : SUB 13 ->   2  5
 2  5 : STA 11 ->   2  6
 2  6 : BRZ  8 ->   2  7
 2  7 : JMP  0 ->   2  0
 2  0 : LDA 12 ->  40  1
40  1 : ADD 10 ->  48  2
48  2 : STA 12 ->  48  3
48  3 : LDA 11 ->   2  4
 2  4 : SUB 13 ->   1  5
 1  5 : STA 11 ->   1  6
 1  6 : BRZ  8 ->   1  7
 1  7 : JMP  0 ->   1  0
 1  0 : LDA 12 ->  48  1
48  1 : ADD 10 ->  56  2
56  2 : STA 12 ->  56  3
56  3 : LDA 11 ->   1  4
 1  4 : SUB 13 ->   0  5
 0  5 : STA 11 ->   0  6
 0  6 : BRZ  8 ->   0  8
 0  8 : LDA 12 ->  56  9
56  9 : STP  0 ->  56 -1
 0  0 : LDA 14 ->   1  1
 1  1 : STA 15 ->   1  2
 1  2 : ADD 13 ->   2  3
 2  3 : STA 14 ->   2  4
 2  4 : LDA 15 ->   1  5
 1  5 : STA 13 ->   1  6
 1  6 : LDA 16 ->   8  7
 8  7 : SUB 17 ->   7  8
 7  8 : BRZ 11 ->   7  9
 7  9 : STA 16 ->   7 10
 7 10 : JMP  0 ->   7  0
 7  0 : LDA 14 ->   2  1
 2  1 : STA 15 ->   2  2
 2  2 : ADD 13 ->   3  3
 3  3 : STA 14 ->   3  4
 3  4 : LDA 15 ->   2  5
 2  5 : STA 13 ->   2  6
 2  6 : LDA 16 ->   7  7
 7  7 : SUB 17 ->   6  8
 6  8 : BRZ 11 ->   6  9
 6  9 : STA 16 ->   6 10
 6 10 : JMP  0 ->   6  0
 6  0 : LDA 14 ->   3  1
 3  1 : STA 15 ->   3  2
 3  2 : ADD 13 ->   5  3
 5  3 : STA 14 ->   5  4
 5  4 : LDA 15 ->   3  5
 3  5 : STA 13 ->   3  6
 3  6 : LDA 16 ->   6  7
 6  7 : SUB 17 ->   5  8
 5  8 : BRZ 11 ->   5  9
 5  9 : STA 16 ->   5 10
 5 10 : JMP  0 ->   5  0
 5  0 : LDA 14 ->   5  1
 5  1 : STA 15 ->   5  2
 5  2 : ADD 13 ->   8  3
 8  3 : STA 14 ->   8  4
 8  4 : LDA 15 ->   5  5
 5  5 : STA 13 ->   5  6
 5  6 : LDA 16 ->   5  7
 5  7 : SUB 17 ->   4  8
 4  8 : BRZ 11 ->   4  9
 4  9 : STA 16 ->   4 10
 4 10 : JMP  0 ->   4  0
 4  0 : LDA 14 ->   8  1
 8  1 : STA 15 ->   8  2
 8  2 : ADD 13 ->  13  3
13  3 : STA 14 ->  13  4
13  4 : LDA 15 ->   8  5
 8  5 : STA 13 ->   8  6
 8  6 : LDA 16 ->   4  7
 4  7 : SUB 17 ->   3  8
 3  8 : BRZ 11 ->   3  9
 3  9 : STA 16 ->   3 10
 3 10 : JMP  0 ->   3  0
 3  0 : LDA 14 ->  13  1
13  1 : STA 15 ->  13  2
13  2 : ADD 13 ->  21  3
21  3 : STA 14 ->  21  4
21  4 : LDA 15 ->  13  5
13  5 : STA 13 ->  13  6
13  6 : LDA 16 ->   3  7
 3  7 : SUB 17 ->   2  8
 2  8 : BRZ 11 ->   2  9
 2  9 : STA 16 ->   2 10
 2 10 : JMP  0 ->   2  0
 2  0 : LDA 14 ->  21  1
21  1 : STA 15 ->  21  2
21  2 : ADD 13 ->  34  3
34  3 : STA 14 ->  34  4
34  4 : LDA 15 ->  21  5
21  5 : STA 13 ->  21  6
21  6 : LDA 16 ->   2  7
 2  7 : SUB 17 ->   1  8
 1  8 : BRZ 11 ->   1  9
 1  9 : STA 16 ->   1 10
 1 10 : JMP  0 ->   1  0
 1  0 : LDA 14 ->  34  1
34  1 : STA 15 ->  34  2
34  2 : ADD 13 ->  55  3
55  3 : STA 14 ->  55  4
55  4 : LDA 15 ->  34  5
34  5 : STA 13 ->  34  6
34  6 : LDA 16 ->   1  7
 1  7 : SUB 17 ->   0  8
 0  8 : BRZ 11 ->   0 11
 0 11 : LDA 14 ->  55 12
55 12 : STP  0 ->  55 -1
 0  0 : LDA 13 ->  32  1
32  1 : ADD 15 ->  60  2
60  2 : STA  5 ->  60  3
60  3 : ADD 16 ->  61  4
61  4 : STA  7 ->  61  5
61  5 : LDA 28 ->   1  6
 1  6 : STA 14 ->   1  7
 1  7 : LDA 29 ->  22  8
22  8 : BRZ 11 ->  22  9
22  9 : STA 15 ->  22 10
22 10 : JMP  0 ->  22  0
22  0 : LDA 13 ->  32  1
32  1 : ADD 15 ->  54  2
54  2 : STA  5 ->  54  3
54  3 : ADD 16 ->  55  4
55  4 : STA  7 ->  55  5
55  5 : LDA 22 ->   2  6
 2  6 : STA 14 ->   2  7
 2  7 : LDA 23 ->  26  8
26  8 : BRZ 11 ->  26  9
26  9 : STA 15 ->  26 10
26 10 : JMP  0 ->  26  0
26  0 : LDA 13 ->  32  1
32  1 : ADD 15 ->  58  2
58  2 : STA  5 ->  58  3
58  3 : ADD 16 ->  59  4
59  4 : STA  7 ->  59  5
59  5 : LDA 26 ->   3  6
 3  6 : STA 14 ->   3  7
 3  7 : LDA 27 ->  30  8
30  8 : BRZ 11 ->  30  9
30  9 : STA 15 ->  30 10
30 10 : JMP  0 ->  30  0
30  0 : LDA 13 ->  32  1
32  1 : ADD 15 ->  62  2
62  2 : STA  5 ->  62  3
62  3 : ADD 16 ->  63  4
63  4 : STA  7 ->  63  5
63  5 : LDA 30 ->   4  6
 4  6 : STA 14 ->   4  7
 4  7 : LDA 31 ->  24  8
24  8 : BRZ 11 ->  24  9
24  9 : STA 15 ->  24 10
24 10 : JMP  0 ->  24  0
24  0 : LDA 13 ->  32  1
32  1 : ADD 15 ->  56  2
56  2 : STA  5 ->  56  3
56  3 : ADD 16 ->  57  4
57  4 : STA  7 ->  57  5
57  5 : LDA 24 ->   5  6
 5  6 : STA 14 ->   5  7
 5  7 : LDA 25 ->  20  8
20  8 : BRZ 11 ->  20  9
20  9 : STA 15 ->  20 10
20 10 : JMP  0 ->  20  0
20  0 : LDA 13 ->  32  1
32  1 : ADD 15 ->  52  2
52  2 : STA  5 ->  52  3
52  3 : ADD 16 ->  53  4
53  4 : STA  7 ->  53  5
53  5 : LDA 20 ->   6  6
 6  6 : STA 14 ->   6  7
 6  7 : LDA 21 ->   0  8
 0  8 : BRZ 11 ->   0 11
 0 11 : LDA 14 ->   6 12
 6 12 : STP  0 ->   6 -1
 0  0 : NOP  0 ->   0  1
 0  1 : NOP  0 ->   0  2
 0  2 : STP  0 ->   0 -1

J[edit]

The reference programs are not supplied in source code form, so in its current form this task is a bit unclear.

Here's one approach which might be sufficiently close to the task requirements:

OPS=: 'nop lda sta add sub brz jmp stp'
 
assemble1=: {{
y=. tolower y
ins=. {.;:y-.":i.10
cod=. 8|(;:OPS) i. ins
val=. {.0".y-.OPS
if. *cod do.
assert. 32>val
val+32*cod
else.
assert. 256>val
val
end.
}}
 
assemble=: {{
if. 0=L. y do.
delim=. {.((tolower y)-.(":i.10),;OPS),LF
y=. delim cut y
end.
code=. [email protected]> y
mem=: code (i.#code)} 32#0
}}
 
exec1=: {{
'cod val'=. 0 32#:pc{mem
pc=: 32|pc+1
select. cod
case. 0 do.
case. 1 do. acc=: val{mem
case. 2 do. mem=: acc val} mem
case. 3 do. acc=: 256|acc+val{mem
case. 4 do. acc=: 256|acc-val{mem
case. 5 do. pc=: 32|pc[^:(*acc) val
case. 6 do. pc=: 32|val
case. 7 do. pc=: __
end.
}}
 
exec=: {{
pc=: acc=: 0
while. 0<:pc do. exec1'' end.
acc
}}

With this implementation, we can assemble and run representations of the five suggested programs:

   exec assemble 'LDA 3; ADD 4; STP; 2; 2'
4
exec assemble 'LDA 12; ADD 10; STA 12; LDA 11; SUB 13; STA 11; BRZ 8; JMP; LDA 12; STP; 8; 7; 0; 1'
56
exec assemble 'LDA 14; STA 15; ADD 13; STA 14; LDA 15; STA 13; LDA 16; SUB 17; BRZ 11; STA 16; JMP; LDA 14; STP; 1; 1; 0; 8; 1'
55
exec assemble 'LDA 13; ADD 15; STA 5; ADD 16; STA 7; NOP; STA 14; NOP; BRZ 11; STA 15; JMP; LDA 14; STP; LDA; 0; 28; 1; 0; 0; 0; 6; 0; 2; 26; 5; 20; 3; 30; 1; 22; 4; 24'
6
exec assemble 'NOP; NOP; STP; NOP; LDA 3; SUB 29; BRZ 18; LDA 3; STA 29; BRZ 14; LDA 1; ADD 31; STA 1; JMP 2; LDA; ADD 31; STA; JMP 2; LDA 3; STA 29; LDA 1; ADD 30; ADD 3; STA 1; LDA; ADD 30; ADD 3; STA; JMP 2; 0; 1; 3'
0

Alternate approach[edit]

Another approach would be to eliminate the 'assemble' command and implement the opcodes as native J commands (which build a representation of the memory space). To conform with J syntax, the right arguments of these opcodes is required (so you need a 0 even for NOP and STP). The implementation of exec remains much the same as before, but it's convenient to have exec save the code to memory. In other words:

opcode=: {{
(m+{.y),}.y
:
x,m opcode y
}}
 
({{((x)=: y opcode)0}}&>32*[email protected]#);:'NOP LDA STA ADD SUB BRZ JMP STP'
 
exec1=: {{
'cod val'=. 0 32#:pc{mem
pc=: 32|pc+1
select. cod
case. 0 do. NB. NOP
case. 1 do. acc=: val{mem NB. LDA
case. 2 do. mem=: acc val} mem NB. STA
case. 3 do. acc=: 256|acc+val{mem NB. ADD
case. 4 do. acc=: 256|acc-val{mem NB. SUB
case. 5 do. pc=: 32|pc[^:(*acc) val NB. BRZ
case. 6 do. pc=: 32|val NB. JMP
case. 7 do. pc=: __ NB. STP
end.
}}
 
exec=: {{
mem=: 32{.y
pc=: acc=: 0
while. 0<:pc do. exec1'' end.
acc
}}

and:

   exec LDA 3 ADD 4 STP 0 2 2
4
exec LDA 12 ADD 10 STA 12 LDA 11 SUB 13 STA 11 BRZ 8 JMP 0 LDA 12 STP 0 8 7 0 1
56
exec LDA 14 STA 15 ADD 13 STA 14 LDA 15 STA 13 LDA 16 SUB 17 BRZ 11 STA 16 JMP 0 LDA 14 STP 0 1 1 0 8 1
55
exec LDA 13 ADD 15 STA 5 ADD 16 STA 7 NOP 0 STA 14 NOP 0 BRZ 11 STA 15 JMP 0 LDA 14 STP 0 LDA 0 0 28 1 0 0 0 6 0 2 26 5 20 3 30 1 22 4 24
6
exec NOP 0 NOP 0 STP 0 NOP 0 LDA 3 SUB 29 BRZ 18 LDA 3 STA 29 BRZ 14 LDA 1 ADD 31 STA 1 JMP 2 LDA 0 ADD 31 STA 0 JMP 2 LDA 3 STA 29 LDA 1 ADD 30 ADD 3 STA 1 LDA 0 ADD 30 ADD 3 STA 0 JMP 2 0 1 3
0

Java[edit]

Translation of: Python
Works with: Java version 8
import static java.lang.Math.floorMod;
import static java.lang.Math.min;
import static java.util.stream.Collectors.toMap;
 
import java.util.AbstractMap.SimpleEntry;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.stream.Stream;
 
public class ComputerZero {
 
private static final int MEM = 32;
 
private static final int NOP = 0;
private static final int LDA = 1;
private static final int STA = 2;
private static final int ADD = 3;
private static final int SUB = 4;
private static final int BRZ = 5;
private static final int JMP = 6;
private static final int STP = 7;
 
private static final Map<String, Integer> OPCODES = Stream.of(
new SimpleEntry<>("NOP", NOP),
new SimpleEntry<>("LDA", LDA),
new SimpleEntry<>("STA", STA),
new SimpleEntry<>("ADD", ADD),
new SimpleEntry<>("SUB", SUB),
new SimpleEntry<>("BRZ", BRZ),
new SimpleEntry<>("JMP", JMP),
new SimpleEntry<>("STP", STP))
.collect(toMap(SimpleEntry::getKey, SimpleEntry::getValue));
 
private static final Pattern RE_INSTRUCTION = Pattern.compile(
"\\s*" +
"(?:(?<label>\\w+):)?" +
"\\s*" +
String.format("(?<opcode>%s)?", String.join("|", OPCODES.keySet())) +
"\\s*" +
"(?<argument>\\w+)?" +
"\\s*" +
"(?:;(?<comment>.+))?");
 
public static class ComputerZeroException extends RuntimeException {
public ComputerZeroException(String msg) {
super(msg);
}
}
 
private static class Instruction {
String opcode;
String argument;
 
public Instruction(String opcode, String argument) {
this.opcode = opcode;
this.argument = argument;
}
}
 
private static class Assembly {
public Iterable<Instruction> instructions;
public Map<String, Integer> labels;
 
public Assembly(Iterable<Instruction> instructions, Map<String, Integer> labels) {
this.instructions = instructions;
this.labels = labels;
}
}
 
public static Assembly parse(String assembly) {
ArrayList<Instruction> instructions = new ArrayList<Instruction>();
HashMap<String, Integer> labels = new HashMap<String, Integer>();
int lineNumber = 0;
 
for (String line : assembly.split("\\R")) {
Matcher matcher = RE_INSTRUCTION.matcher(line);
 
if (!matcher.matches()) {
throw new ComputerZeroException(String.format("%s %d", line, lineNumber));
}
 
if (matcher.group("label") != null) {
labels.put(matcher.group("label"), lineNumber);
}
 
instructions.add(new Instruction(matcher.group("opcode"), matcher.group("argument")));
lineNumber++;
}
 
return new Assembly(instructions, labels);
}
 
public static Integer[] compile(Assembly assembly) {
ArrayList<Integer> bytecode = new ArrayList<Integer>();
 
for (Instruction instruction : assembly.instructions) {
int argument;
if (instruction.argument == null) {
argument = 0;
} else if (instruction.argument.matches("\\d+")) {
argument = Integer.parseInt(instruction.argument);
} else {
argument = assembly.labels.getOrDefault(instruction.argument, 0);
}
 
if (instruction.opcode != null) {
bytecode.add(OPCODES.get(instruction.opcode) << 5 | argument);
} else {
bytecode.add(argument);
}
}
 
return bytecode.toArray(new Integer[0]);
}
 
public static int run(Integer[] bytecode) {
int accumulator = 0;
int instruction_pointer = 0;
Integer[] memory = new Integer[MEM];
Arrays.fill(memory, 0);
System.arraycopy(bytecode, 0, memory, 0, min(MEM, bytecode.length));
 
vm: while (instruction_pointer < MEM) {
int operation = memory[instruction_pointer] >> 5;
int argument = memory[instruction_pointer] & 0b11111;
instruction_pointer++;
 
switch (operation) {
case NOP:
continue;
case LDA:
accumulator = memory[argument];
break;
case STA:
memory[argument] = accumulator;
break;
case ADD:
accumulator = floorMod(accumulator + memory[argument], 256);
break;
case SUB:
accumulator = floorMod(accumulator - memory[argument], 256);
break;
case BRZ:
if (accumulator == 0) {
instruction_pointer = argument;
}
break;
case JMP:
instruction_pointer = argument;
break;
case STP:
break vm;
default:
throw new ComputerZeroException(
String.format("error: %d %d", operation, argument));
}
 
}
 
return accumulator;
}
 
public static int run(String source) {
return run(compile(parse(source)));
}
 
public static final List<String> TEST_CASES = Arrays.asList(
String.join("\n",
" LDA x",
" ADD y  ; accumulator = x + y",
" STP",
"x: 2",
"y: 2"),
String.join("\n",
"loop: LDA prodt",
" ADD x",
" STA prodt",
" LDA y",
" SUB one",
" STA y",
" BRZ done",
" JMP loop",
"done: LDA prodt  ; to display it",
" STP",
"x: 8",
"y: 7",
"prodt: 0",
"one: 1"),
String.join("\n",
"loop: LDA n",
" STA temp",
" ADD m",
" STA n",
" LDA temp",
" STA m",
" LDA count",
" SUB one",
" BRZ done",
" STA count",
" JMP loop",
"done: LDA n  ; to display it",
" STP",
"m: 1",
"n: 1",
"temp: 0",
"count: 8  ; valid range: 1-11",
"one: 1"),
String.join("\n",
"start: LDA load",
" ADD car  ; head of list",
" STA ldcar",
" ADD one",
" STA ldcdr  ; next CONS cell",
"ldcar: NOP",
" STA value",
"ldcdr: NOP",
" BRZ done  ; 0 stands for NIL",
" STA car",
" JMP start",
"done: LDA value  ; CAR of last CONS",
" STP",
"load: LDA 0",
"value: 0",
"car: 28",
"one: 1",
"  ; order of CONS cells",
"  ; in memory",
"  ; does not matter",
" 6",
" 0  ; 0 stands for NIL",
" 2  ; (CADR ls)",
" 26  ; (CDDR ls) -- etc.",
" 5",
" 20",
" 3",
" 30",
" 1  ; value of (CAR ls)",
" 22  ; points to (CDR ls)",
" 4",
" 24"),
String.join("\n",
"p: 0  ; NOP in first round",
"c: 0",
"start: STP  ; wait for p's move",
"pmove: NOP",
" LDA pmove",
" SUB cmove",
" BRZ same",
" LDA pmove",
" STA cmove  ; tit for tat",
" BRZ cdeft",
" LDA c  ; p defected, c did not",
" ADD three",
" STA c",
" JMP start",
"cdeft: LDA p",
" ADD three",
" STA p",
" JMP start",
"same: LDA pmove",
" STA cmove  ; tit for tat",
" LDA p",
" ADD one",
" ADD pmove",
" STA p",
" LDA c",
" ADD one",
" ADD pmove",
" STA c",
" JMP start",
"cmove: 0  ; co-operate initially",
"one: 1",
"three: 3 "),
String.join("\n",
"LDA 3",
"SUB 4",
"STP 0",
" 0",
" 255"),
String.join("\n",
"LDA 3",
"SUB 4",
"STP 0",
" 0",
" 1"),
String.join("\n",
"LDA 3",
"ADD 4",
"STP 0",
" 1",
" 255")
 
);
 
public static void main(String[] args) {
for (String source : TEST_CASES) {
System.out.println(run(source));
}
}
}
 
Output:
4
56
55
6
0
1
255
0

Julia[edit]

mutable struct ComputerZero
ip::Int
ram::Vector{UInt8}
accum::UInt8
isready::Bool
end
function ComputerZero(program)
memory = zeros(UInt8, 32)
for i in 1:min(32, length(program))
memory[i] = program[i]
end
return ComputerZero(1, memory, 0, true)
end
 
NOP(c) = (c.ip = mod1(c.ip + 1, 32))
LDA(c) = (c.accum = c.ram[c.ram[c.ip] & 0b00011111 + 1]; c.ip = mod1(c.ip + 1, 32))
STA(c) = (c.ram[c.ram[c.ip] & 0b00011111 + 1] = c.accum; c.ip = mod1(c.ip + 1, 32))
ADD(c) = (c.accum += c.ram[c.ram[c.ip] & 0b00011111 + 1]; c.ip = mod1(c.ip + 1, 32))
SUB(c) = (c.accum -= c.ram[c.ram[c.ip] & 0b00011111 + 1]; c.ip = mod1(c.ip + 1, 32))
BRZ(c) = (c.ip = (c.accum == 0) ? c.ram[c.ip] & 0b00011111 + 1 : mod1(c.ip + 1, 32))
JMP(c) = (c.ip = c.ram[c.ip] & 0b00011111 + 1)
STP(c) = (println("Program completed with accumulator value $(c.accum).\n"); c.isready = false)
 
const step = [NOP, LDA, STA, ADD, SUB, BRZ, JMP, STP]
const instructions = ["NOP", "LDA", "STA", "ADD", "SUB", "BRZ", "JMP", "STP"]
const assemblywords = Dict(s => i - 1 for (i, s) in pairs(instructions))
 
function run(compzero::ComputerZero, debug = false)
while compzero.isready
instruction = compzero.ram[compzero.ip]
opcode, operand = instruction >> 5 + 1, instruction & 0b00011111
debug && println("op $(instructions[opcode]), operand $operand")
step[opcode](compzero)
end
return compzero.accum
end
run(program::Vector, debug = false) = run(ComputerZero(program), debug)
 
function compile(text::String)
bin, lines = UInt8[], 0
for line in strip.(split(text, "\n"))
lines += 1
if isempty(line)
push!(bin, 0)
elseif (m = match(r"(\w\w\w)\s+(\d\d?)", line)) != nothing
push!(bin, UInt8((assemblywords[m.captures[1]] << 5) | parse(UInt8, m.captures[2])))
elseif (m = match(r"(\w\w\w)", line)) != nothing
push!(bin, UInt8(assemblywords[m.match] << 5))
elseif (m = match(r"\d\d?", line)) != nothing
push!(bin, parse(UInt8, m.match))
else
error("Compilation error at line $lines: error parsing <$line>")
end
end
println("Compiled $lines lines.")
return bin
end
 
const testprograms = [
"""
LDA 3
ADD 4
STP
2
2
"
"",
"""
LDA 12
ADD 10
STA 12
LDA 11
SUB 13
STA 11
BRZ 8
JMP 0
LDA 12
STP
8
7
0
1
"
"",
"""
LDA 14
STA 15
ADD 13
STA 14
LDA 15
STA 13
LDA 16
SUB 17
BRZ 11
STA 16
JMP 0
LDA 14
STP
1
1
0
8
1
"
"",
"""
LDA 13
ADD 15
STA 5
ADD 16
STA 7
NOP
STA 14
NOP
BRZ 11
STA 15
JMP 0
LDA 14
STP
LDA 0
0
28
1
 
 
 
6
0
2
26
5
20
3
30
1
22
4
24
"
"",
"""
0
0
STP
NOP
LDA 3
SUB 29
BRZ 18
LDA 3
STA 29
BRZ 14
LDA 1
ADD 31
STA 1
JMP 2
LDA 0
ADD 31
STA 0
JMP 2
LDA 3
STA 29
LDA 0
ADD 30
ADD 3
STA 0
LDA 1
ADD 30
ADD 3
STA 1
JMP 2
0
1
3
"
""
]
 
for t in testprograms
run(compile(t))
end
 
Output:
Compiled 6 lines.
Program completed with accumulator value 4.

Compiled 15 lines.
Program completed with accumulator value 56.

Compiled 19 lines.
Program completed with accumulator value 55.

Compiled 33 lines.
Program completed with accumulator value 6. 

Compiled 33 lines.
Program completed with accumulator value 0.

Interpreter version with labels[edit]

Uses the Python examples.

function interpret(text::String)
ip, accum, isready, ram = 0x1, 0x0, true, zeros(UInt8, 32)
NOP() = (ip = mod1(ip + 1, 32))
LDA() = (accum = ram[ram[ip] & 0b00011111 + 1]; ip = mod1(ip + 1, 32))
STA() = (ram[ram[ip] & 0b00011111 + 1] = accum; ip = mod1(ip + 1, 32))
ADD() = (accum += ram[ram[ip] & 0b00011111 + 1]; ip = mod1(ip + 1, 32))
SUB() = (accum -= ram[ram[ip] & 0b00011111 + 1]; ip = mod1(ip + 1, 32))
BRZ() = (ip = (accum == 0) ? ram[ip] & 0b00011111 + 1 : mod1(ip + 1, 32))
JMP() = (ip = ram[ip] & 0b00011111 + 1)
STP() = (println("Program completed with accumulator value $(accum).\n"); isready = false)
step = [NOP, LDA, STA, ADD, SUB, BRZ, JMP, STP]
assemblywords = Dict(s => i - 1 for (i, s) in pairs(string.(step)))
labels = Dict{String, Int}()
arglabels = Dict{Int, Tuple{Int, String}}()
for (i, line) in pairs(strip.(split(text, "\n")))
i > 32 && break
line = replace(line, r";.*$" => "") # remove comment
if occursin(":", line)
label, line = split(line, ":", limit = 2)
haskey(labels, label) && error("Duplicate label at line $i")
labels[strip(label)] = i - 1
end
if isempty(line)
ram[i] = 0
elseif (m = match(r"(\w\w\w)\s+([a-zA-Z]\w*)", line)) != nothing
arglabels[i] = (UInt8((assemblywords[m.captures[1]] << 5)), m.captures[2])
elseif (m = match(r"(\w\w\w)\s+(\d\d*)", line)) != nothing
ram[i] = UInt8((assemblywords[m.captures[1]] << 5) | parse(UInt8, m.captures[2]))
elseif (m = match(r"([a-zA-Z]\w*)", line)) != nothing
ram[i] = UInt8(assemblywords[m.match] << 5)
elseif (m = match(r"\d\d*", line)) != nothing
ram[i] = parse(UInt8, m.match)
else
error("Compilation error at line $i: error parsing <$line>")
end
end
for (i, t) in arglabels
ram[i] = t[1] | labels[t[2]]
end
while isready
step[ram[ip] >> 5 + 1]()
end
return accum
end
 
const testprograms = [
"""
LDA 3
ADD 4
STP
2
2
"
"",
"""
LDA 12
ADD 10
STA 12
LDA 11
SUB 13
STA 11
BRZ 8
JMP 0
LDA 12
STP
8
7
0
1
"
"",
"""
LDA 14
STA 15
ADD 13
STA 14
LDA 15
STA 13
LDA 16
SUB 17
BRZ 11
STA 16
JMP 0
LDA 14
STP
1
1
0
8
1
"
"",
"""
LDA 13
ADD 15
STA 5
ADD 16
STA 7
NOP
STA 14
NOP
BRZ 11
STA 15
JMP 0
LDA 14
STP
LDA 0
0
28
1
 
 
 
6
0
2
26
5
20
3
30
1
22
4
24
"
"",
"""
0
0
STP
NOP
LDA 3
SUB 29
BRZ 18
LDA 3
STA 29
BRZ 14
LDA 1
ADD 31
STA 1
JMP 2
LDA 0
ADD 31
STA 0
JMP 2
LDA 3
STA 29
LDA 0
ADD 30
ADD 3
STA 0
LDA 1
ADD 30
ADD 3
STA 1
JMP 2
0
1
3
"
"",
"""\
LDA x
ADD y  ; accumulator = x + y
STP
x: 2
y: 2
"
"",
"""\
loop: LDA prodt
ADD x
STA prodt
LDA y
SUB one
STA y
BRZ done
JMP loop
done: LDA prodt  ; to display it
STP
x: 8
y: 7
prodt: 0
one: 1
"
"",
"""\
loop: LDA n
STA temp
ADD m
STA n
LDA temp
STA m
LDA count
SUB one
BRZ done
STA count
JMP loop
done: LDA n  ; to display it
STP
m: 1
n: 1
temp: 0
count: 8  ; valid range: 1-11
one: 1
"
"",
"""\
start: LDA load
ADD car  ; head of list
STA ldcar
ADD one
STA ldcdr  ; next CONS cell
ldcar: NOP
STA value
ldcdr: NOP
BRZ done  ; 0 stands for NIL
STA car
JMP start
done: LDA value  ; CAR of last CONS
STP
load: LDA 0
value: 0
car: 28
one: 1
 ; order of CONS cells
 ; in memory
 ; does not matter
6
0  ; 0 stands for NIL
2  ; (CADR ls)
26  ; (CDDR ls) -- etc.
5
20
3
30
1  ; value of (CAR ls)
22  ; points to (CDR ls)
4
24
"
"",
"""\
p: 0  ; NOP in first round
c: 0
start: STP  ; wait for p's move
pmove: NOP
LDA pmove
SUB cmove
BRZ same
LDA pmove
STA cmove  ; tit for tat
BRZ cdeft
LDA c  ; p defected, c did not
ADD three
STA c
JMP start
cdeft: LDA p
ADD three
STA p
JMP start
same: LDA pmove
STA cmove  ; tit for tat
LDA p
ADD one
ADD pmove
STA p
LDA c
ADD one
ADD pmove
STA c
JMP start
cmove: 0  ; co-operate initially
one: 1
three: 3
"
"",
"""\
LDA 3
SUB 4
STP 0
0
255
"
"",
"""\
LDA 3
SUB 4
STP 0
0
1
"
"",
"""\
LDA 3
ADD 4
STP 0
1
255
"
"",
]
 
for t in testprograms
interpret(t)
end
 
Output:
Program completed with accumulator value 4.

Program completed with accumulator value 56.

Program completed with accumulator value 55.

Program completed with accumulator value 6.

Program completed with accumulator value 0.

Program completed with accumulator value 4.

Program completed with accumulator value 56.

Program completed with accumulator value 55.

Program completed with accumulator value 6.

Program completed with accumulator value 0.

Program completed with accumulator value 1.

Program completed with accumulator value 255.

Program completed with accumulator value 0.

Lua[edit]

Execute (2+2, 7*8)[edit]

Per primary task, just execute first two examples:

vmz = {
pc = 0,
acc = 0,
mem = { [0]=0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0 },
b2oa = function(byte) return math.floor(byte / 32), byte % 32 end,
boot = function(self) self.pc, self.acc = 0, 0 for pc=0,31 do self.mem[pc]=0 end return self end,
load = function(self, bytes) for pc = 0, 31 do self.mem[pc]=bytes[pc] or 0 end return self end,
clam = function(n) if n<0 then n=n+256 elseif n>255 then n=n-256 end return n end,
opfn = {[0]=
function(self,addr) self.pc=self.pc+1 return true end, -- NOP
function(self,addr) self.acc=self.mem[addr] self.pc=self.pc+1 return true end, -- LDA
function(self,addr) self.mem[addr]=self.acc self.pc=self.pc+1 return true end, -- STA
function(self,addr) self.acc=self.clam(self.acc+self.mem[addr]) self.pc=self.pc+1 return true end, -- ADD
function(self,addr) self.acc=self.clam(self.acc-self.mem[addr]) self.pc=self.pc+1 return true end, -- SUB
function(self,addr) if (self.acc==0) then self.pc=addr else self.pc=self.pc+1 end return true end, -- BRZ
function(self,addr) self.pc=addr return true end, -- JMP
function(self,addr) self.pc=self.pc+1 return false end, -- STP
},
step = function(self)
local oper, addr = self.b2oa(self.mem[self.pc])
return self.opfn[oper](self,addr)
end,
exec = function(self)
while self.pc < 32 and self:step() do end
return self
end,
}
-- object code derived from js sim code
print("2 + 2 = " .. vmz:boot():load({[0]=35,100,224,2,2}):exec().acc)
print("7 x 8 = " .. vmz:boot():load({[0]=44,106,76,43,141,75,168,192,44,224,8,7,0,1}):exec().acc)
Output:
2 + 2 = 4
7 x 8 = 56

Disassembler (7*8)[edit]

Assembly syntax doesn't seem well-specified (except as shown in descriptive text, which is presumably just pseudocode), but next step might be to add a minimal disassembler:

vmz.dism = function(self)
local mnem, imax = { [0]="NOP", "LDA", "STA", "ADD", "SUB", "BRZ", "JMP", "STP" }
for pc = 31,0,-1 do imax=pc if self.mem[pc]~=0 then break end end
local result, pretty = "", "  %3s %2d\n"
for i = 0, imax do
local oper, addr = self.b2oa(self.mem[i])
result = result .. pretty:format(mnem[oper], addr)
end
return result
end
vmz:boot():load({[0]=44,106,76,43,141,75,168,192,44,224,8,7,0,1})
print("Disassembly of 7 x 8 (PRE-RUN):")
print(vmz:dism())
print("Disassembly of 7 x 8 (POST-RUN):")
print(vmz:exec():dism())
Output:
Disassembly of 7 x 8 (PRE-RUN):
  LDA 12
  ADD 10
  STA 12
  LDA 11
  SUB 13
  STA 11
  BRZ  8
  JMP  0
  LDA 12
  STP  0
  NOP  8
  NOP  7
  NOP  0
  NOP  1

Disassembly of 7 x 8 (POST-RUN):
  LDA 12
  ADD 10
  STA 12
  LDA 11
  SUB 13
  STA 11
  BRZ  8
  JMP  0
  LDA 12
  STP  0
  NOP  8
  NOP  0
  LDA 24
  NOP  1

Assembler (fibo, list)[edit]

Add an assembler (same minimal syntax as disassembler) for the next two examples:

-- <statement> ::= <opcode> <address>
vmz.assm = function(self, source)
local function oa2b(oper, addr) return oper * 32 + addr end
local pc, objc = 0, { NOP=0, LDA=1, STA=2, ADD=3, SUB=4, BRZ=5, JMP=6, STP=7 }
for oper, addr in source:gmatch("%s*(%a%a%a)%s*(%d*)") do
self.mem[pc] = oa2b(objc[oper], tonumber(addr) or 0)
pc = pc + 1
end
return self
end
 
srcfibo = "LDA 14 STA 15 ADD 13 STA 14 LDA 15 STA 13 LDA 16 SUB 17 BRZ 11 STA 16 JMP 0 LDA 14 STP 0 NOP 1 NOP 1 NOP 0 NOP 8 NOP 1"
print("Fibonacci = " .. vmz:boot():assm(srcfibo):exec().acc)
 
srclist = [[
LDA 13 ADD 15 STA 5 ADD 16 STA 7 NOP 0 STA 14 NOP 0
BRZ 11 STA 15 JMP 0 LDA 14 STP 0 LDA 0 NOP 0 NOP 28
NOP 1 NOP 0 NOP 0 NOP 0 NOP 6 NOP 0 NOP 2 NOP 26
NOP 5 NOP 20 NOP 3 NOP 30 NOP 1 NOP 22 NOP 4 NOP 24
]]
print("Linked list = " .. vmz:boot():assm(srclist):exec().acc)
Output:
Fibonacci = 55
Linked list = 6

Prisoner[edit]

Some additional helper routines, then multiple rounds:

vmz.peek = function(self,addr) return self.mem[addr] end
vmz.poke = function(self,addr,byte) self.mem[addr]=byte end
vmz.entr = function(self,byte) self.mem[self.pc]=byte self.pc=self.pc+1 end
-- derived from the javascript "object code", rather than the descriptive "source code", as they appear to differ
srcpris = [[
NOP 0 NOP 0 STP 0 NOP 0 LDA 3 SUB 29 BRZ 18 LDA 3 STA 29 BRZ 14 LDA 1 ADD 31 STA 1 JMP 2 LDA 0 ADD 31
STA 0 JMP 2 LDA 3 STA 29 LDA 1 ADD 30 ADD 3 STA 1 LDA 0 ADD 30 ADD 3 STA 0 JMP 2 NOP 0 NOP 1 NOP 3
]]
print("\nPrisoner (priming) = " .. vmz:boot():assm(srcpris):exec().acc)
-- play five rounds,ie: poke 0 or 1 into mem[3], pc+=1, exec again
mvnm = {[0]="coop", "defe"}
for r = 1, 5 do
local move = r%2 -- artificial stupidity?
vmz:entr(move)
vmz:exec()
print("Round: " .. r .. " Move: " .. mvnm[move] .. " Player: " .. vmz:peek(0) .. " Computer: " .. vmz:peek(1))
end
Output:
Prisoner (priming) = 0
Round: 1  Move: defe  Player: 0  Computer: 3
Round: 2  Move: coop  Player: 3  Computer: 3
Round: 3  Move: defe  Player: 3  Computer: 6
Round: 4  Move: coop  Player: 6  Computer: 6
Round: 5  Move: defe  Player: 6  Computer: 9

Phix[edit]

Assumes there is no need for an "assembler", just a runtime interpreter. Output matches Algol 68.

with javascript_semantics
constant NOP = 0b000_00000, -- no operation
         LDA = 0b001_00000, -- load accumulator, a := memory [xxxxx]
         STA = 0b010_00000, -- store accumulator, memory [xxxxx] := a
         ADD = 0b011_00000, -- add, a := a + memory [xxxxx]
         SUB = 0b100_00000, -- subtract, a := a – memory [xxxxx]
         BRZ = 0b101_00000, -- branch on zero, if a = 0 then goto xxxxx
         JMP = 0b110_00000, -- jump, goto xxxxx
         STP = 0b111_00000, -- stop
         OP  = 0b111_00000, -- operator mask
         ARG = 0b000_11111  -- memory location (0 based)

procedure execute(string name, sequence program)
    sequence memory = deep_copy(program)
    integer pc = 1, a = 0
    while true do
        integer ppc = memory[pc],
                op = and_bitsu(ppc,OP),
                arg = and_bits(ppc,ARG)+1
        pc += 1
        switch op do
            case NOP:   break
            case LDA:   a = memory[arg]
            case STA:   memory[arg] = a
            case ADD:   a = and_bitsu(a+memory[arg],#FF)
            case SUB:   a = and_bitsu(a-memory[arg],#FF)
            case BRZ:   if a=0 then pc = arg end if
            case JMP:   pc = arg
            case STP:   printf(1,"%12s: %3d\n",{name,a})
                        return
        end switch
    end while
end procedure

execute("2+2",{LDA+3, ADD+4, STP, 2,2})
execute("7*8",{LDA+12, ADD+10, STA+12, LDA+11, SUB+13, STA+11, BRZ+8, JMP+0,
               LDA+12, STP, 8,7,0,1})
execute("fibonacci",{LDA+14, STA+15, ADD+13, STA+14, LDA+15, STA+13, LDA+16,
                     SUB+17, BRZ+11, STA+16, JMP+0,  LDA+14, STP, 1,1,0,8,1})
execute("linkedList",{LDA+13, ADD+15, STA+5, ADD+16, STA+7, NOP, STA+14, NOP,
                      BRZ+11, STA+15, JMP+0, LDA+14, STP, LDA+0, 0,28,1,0,0,
                      0,6,0,2,26,5,20,3,30,1,22,4,24})
execute("prisoner",{NOP, NOP, STP, 0, LDA+3, SUB+29, BRZ+18, LDA+3, STA+29, 
                    BRZ+14, LDA+1, ADD+31, STA+1, JMP+2, LDA+0, ADD+31, STA+0,
                    JMP+2, LDA+3, STA+29, LDA+1, ADD+30, ADD+3, STA+1, LDA+0,
                    ADD+30, ADD+3, STA+0, JMP+2, 0, 1, 3})
-- subtractions yielding negative results
execute("0-255",{LDA+3,SUB+4,STP, 0,255})
execute("0-1",{LDA+3, SUB+4, STP, 0,1})
-- overflow on addition
execute("1+255",{LDA+3, ADD+4, STP, 1, 255})

You could of course define the programs using (say) 0b001_00011 instead of LDA+3.

Output:
         2+2:   4
         7*8:  56
   fibonacci:  55
  linkedList:   6
    prisoner:   0
       0-255:   1
         0-1: 255
       1+255:   0

Python[edit]

"""Computer/zero Assembly emulator. Requires Python >= 3.7"""
 
import re
 
from typing import Dict
from typing import Iterable
from typing import List
from typing import NamedTuple
from typing import Optional
from typing import Tuple
 
 
NOP = 0b000
LDA = 0b001
STA = 0b010
ADD = 0b011
SUB = 0b100
BRZ = 0b101
JMP = 0b110
STP = 0b111
 
OPCODES = {
"NOP": NOP,
"LDA": LDA,
"STA": STA,
"ADD": ADD,
"SUB": SUB,
"BRZ": BRZ,
"JMP": JMP,
"STP": STP,
}
 
RE_INSTRUCTION = re.compile(
r"\s*"
r"(?:(?P<label>\w+):)?"
r"\s*"
rf"(?P<opcode>{'|'.join(OPCODES)})?"
r"\s*"
r"(?P<argument>\w+)?"
r"\s*"
r"(?:;(?P<comment>[\w\s]+))?"
)
 
 
class AssemblySyntaxError(Exception):
pass
 
 
class Instruction(NamedTuple):
label: Optional[str]
opcode: Optional[str]
argument: Optional[str]
comment: Optional[str]
 
 
def parse(assembly: str) -> Tuple[List[Instruction], Dict[str, int]]:
instructions: List[Instruction] = []
labels: Dict[str, int] = {}
linenum: int = 0
 
for line in assembly.split("\n"):
match = RE_INSTRUCTION.match(line)
 
if not match:
raise AssemblySyntaxError(f"{line}: {linenum}")
 
instructions.append(Instruction(**match.groupdict()))
label = match.group(1)
if label:
labels[label] = linenum
 
linenum += 1
 
return instructions, labels
 
 
def compile(instructions: List[Instruction], labels: Dict[str, int]) -> Iterable[int]:
for instruction in instructions:
if instruction.argument is None:
argument = 0
elif instruction.argument.isnumeric():
argument = int(instruction.argument)
else:
argument = labels[instruction.argument]
 
if instruction.opcode:
yield OPCODES[instruction.opcode] << 5 | argument
else:
yield argument
 
 
def run(bytecode: bytes) -> int:
accumulator = 0
program_counter = 0
memory = list(bytecode)[:32] + [0 for _ in range(32 - len(bytecode))]
 
while program_counter < 32:
operation = memory[program_counter] >> 5
argument = memory[program_counter] & 0b11111
program_counter += 1
 
if operation == NOP:
continue
elif operation == LDA:
accumulator = memory[argument]
elif operation == STA:
memory[argument] = accumulator
elif operation == ADD:
accumulator = (accumulator + memory[argument]) % 256
elif operation == SUB:
accumulator = (accumulator - memory[argument]) % 256
elif operation == BRZ:
if accumulator == 0:
program_counter = argument
elif operation == JMP:
program_counter = argument
elif operation == STP:
break
else:
raise Exception(f"error: {operation} {argument}")
 
return accumulator
 
 
SAMPLES = [
"""\
LDA x
ADD y  ; accumulator = x + y
STP
x: 2
y: 2
"""
,
"""\
loop: LDA prodt
ADD x
STA prodt
LDA y
SUB one
STA y
BRZ done
JMP loop
done: LDA prodt  ; to display it
STP
x: 8
y: 7
prodt: 0
one: 1
"""
,
"""\
loop: LDA n
STA temp
ADD m
STA n
LDA temp
STA m
LDA count
SUB one
BRZ done
STA count
JMP loop
done: LDA n  ; to display it
STP
m: 1
n: 1
temp: 0
count: 8  ; valid range: 1-11
one: 1
"""
,
"""\
start: LDA load
ADD car  ; head of list
STA ldcar
ADD one
STA ldcdr  ; next CONS cell
ldcar: NOP
STA value
ldcdr: NOP
BRZ done  ; 0 stands for NIL
STA car
JMP start
done: LDA value  ; CAR of last CONS
STP
load: LDA 0
value: 0
car: 28
one: 1
 ; order of CONS cells
 ; in memory
 ; does not matter
6
0  ; 0 stands for NIL
2  ; (CADR ls)
26  ; (CDDR ls) -- etc.
5
20
3
30
1  ; value of (CAR ls)
22  ; points to (CDR ls)
4
24
"""
,
"""\
p: 0  ; NOP in first round
c: 0
start: STP  ; wait for p's move
pmove: NOP
LDA pmove
SUB cmove
BRZ same
LDA pmove
STA cmove  ; tit for tat
BRZ cdeft
LDA c  ; p defected, c did not
ADD three
STA c
JMP start
cdeft: LDA p
ADD three
STA p
JMP start
same: LDA pmove
STA cmove  ; tit for tat
LDA p
ADD one
ADD pmove
STA p
LDA c
ADD one
ADD pmove
STA c
JMP start
cmove: 0  ; co-operate initially
one: 1
three: 3
"""
,
"""\
LDA 3
SUB 4
STP 0
0
255
"""
,
"""\
LDA 3
SUB 4
STP 0
0
1
"""
,
"""\
LDA 3
ADD 4
STP 0
1
255
"""
,
]
 
 
def main() -> None:
for sample in SAMPLES:
instructions, labels = parse(sample)
bytecode = bytes(compile(instructions, labels))
result = run(bytecode)
print(result)
 
 
if __name__ == "__main__":
main()
 
Output:
4
56
55
6
0
1
255
0

Wren[edit]

As I'm unclear whether the interpreter should be able to deal with labels, the programs all use literal memory addresses for now. Output is in decimal.

Although I've entered the fifth program, it just returns 0 when reaching the STP instruction. I'm unclear how we can make it interactive without having another instruction though possibly, if STP had address bits other than 0, this could signal that user input was required.

var NOP = 0
var LDA = 1
var STA = 2
var ADD = 3
var SUB = 4
var BRZ = 5
var JMP = 6
var STP = 7
 
var ops = {"NOP": NOP, "LDA": LDA, "STA": STA, "ADD": ADD,
"SUB": SUB, "BRZ": BRZ, "JMP": JMP, "STP": STP}
 
var load = Fn.new { |prog|
var mem = List.filled(32, 0)
var lines = prog.trimEnd().split("\n")
for (i in 0...lines.count) {
var line = lines[i].trim()
var split = line.split(" ")
var instr = split[0]
var addr = 0
if (split.count == 2) addr = Num.fromString(split[1])
if (ops[instr]) {
mem[i] = ops[instr] * 32 + addr
} else {
var v = Num.fromString(instr)
if (v) mem[i] = v
}
}
return mem
}
 
var output = Fn.new { |acc|
System.print(acc)
}
 
var interp = Fn.new { |prog|
var acc = 0
var pc = 0
var mem = load.call(prog)
while (true) {
var instr = mem[pc] >> 5
var addr = mem[pc] % 32
pc = pc + 1
if (instr == LDA) {
acc = mem[addr]
} else if (instr == STA) {
mem[addr] = acc
} else if (instr == ADD) {
acc = acc + mem[addr]
if (acc > 255) acc = acc - 256
} else if (instr == SUB) {
acc = acc - mem[addr]
if (acc < 0) acc = acc + 256
} else if (instr == BRZ) {
if (acc == 0) pc = addr
} else if (instr == JMP) {
pc = addr
}
if (instr == STP || pc > 31) break
}
output.call(acc)
}
 
var progs = [
"""
LDA 3
ADD 4
STP
2
2
"
"",
"""
LDA 12
ADD 10
STA 12
LDA 11
SUB 13
STA 11
BRZ 8
JMP 0
LDA 12
STP
8
7
0
1
"
"",
"""
LDA 14
STA 15
ADD 13
STA 14
LDA 15
STA 13
LDA 16
SUB 17
BRZ 11
STA 16
JMP 0
LDA 14
STP
1
1
0
8
1
"
"",
"""
LDA 13
ADD 15
STA 5
ADD 16
STA 7
NOP
STA 14
NOP
BRZ 11
STA 15
JMP 0
LDA 14
STP
LDA 0
0
28
1
 
 
 
6
0
2
26
5
20
3
30
1
22
4
24
"
"",
"""
0
0
STP
NOP
LDA 3
SUB 29
BRZ 18
LDA 3
STA 29
BRZ 14
LDA 1
ADD 31
STA 1
JMP 2
LDA 0
ADD 31
STA 0
JMP 2
LDA 3
STA 29
LDA 0
ADD 30
ADD 3
STA 0
LDA 1
ADD 30
ADD 3
STA 1
JMP 2
0
1
3
"
""
]
for (prog in progs) interp.call(prog)
Output:
4
56
55
6
0

Z80 Assembly[edit]

Output is in hexadecimal but is otherwise correct.

org &1000
PrintChar equ &BB5A
 
;reg usage:
;DE = VM'S Program Counter
;IXL = VM's Accumulator
main:
ld ixl,0
ld de,Computer_Zero_RAM_2_plus_2
call Computer_Zero_VM
ld a,ixl
call ShowHex ;output to Amstrad CPC's screen
call NewLine
 
ld ixl,0
ld de,Computer_Zero_RAM_7x8
call Computer_Zero_VM
ld a,ixl
jp ShowHex ;output and return to basic.
 
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;these two functions are related to displaying the output
; and have nothing to do with the virtual machine itself.
ShowHex:
push af
and %11110000
rrca
rrca
rrca
rrca
call PrintHexChar
pop af
and %00001111
;call PrintHexChar
;execution flows into it naturally.
PrintHexChar:
;converts hex to ascii
or a ;Clear Carry Flag
daa
add a,&F0
adc a,&40
jp PrintChar
 
NewLine:
push af
ld a,13
call PrintChar
ld a,10
call PrintChar
pop af
ret
 
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
Computer_Zero_VM:
ld a,(de) ;opcode fetch
call UnpackOpcode ;stores opcode in B, operand in C
push de
ld de,Opcode_Table
ld a,b
rlca ;index times 2 for word data
 
ld e,a
ld a,(de)
ld L,a
inc de
ld a,(de)
ld h,a ;LD HL,(DE)
 
pop de
jp (hl)
;register state after this jump:
;DE = program counter
;HL = address of instruction implementation
;C = operand of the instruction we're about to execute
;IXL = accumulator
 
 
 
overhead:
ld a,e
inc a
and %00011111
;ensures we stay within the 32 byte address space.
ld e,a
jp Computer_Zero_VM
 
 
UnpackOpcode:
push af
and %11100000
rlca
rlca
rlca
ld b,a ;opcode in B
pop af
and %00011111
ld c,a ;operand in C
dummy:
ret
 
 
 
align 256 ;ensures the following table is page-aligned
;this lets us index it much faster.
Opcode_Table:
dw vmNOP
dw vmLDA
dw vmSTA
dw vmADD
dw vmSUB
dw vmBRZ
dw vmJMP
dw vmSTP
 
vmNOP:
jp overhead ;do nothing
vmLDA:
push de
ld e,c ;offset DE by the operand
ld a,(de) ;load from that address
ld ixl,a ;and store it in the accumulator
pop de
jp overhead
vmSTA:
push de
ld e,c ;offset DE by the operand
ld a,ixl ;get the accumulator
ld (de),a ;store it into (DE)
pop de
jp overhead
vmADD:
push de
ld e,c ;offset DE by the operand
ld a,(de) ;load from that address
add ixl ;and add that value to the accumulator
ld ixl,a ;then set the new accumulator
pop de
jp overhead
vmSUB:
push de
ld e,c ;offset DE by the operand
ld a,(de)
ld b,a
ld a,ixl
sub b
ld ixl,a
pop de
noBRZ:
jp overhead
vmBRZ:
ld a,ixl
or a
jr nz, noBRZ
vmJMP:
ld e,c
jp Computer_Zero_VM
vmSTP:
ret ;return to main
 
align 256
Computer_Zero_RAM_2_plus_2:
db %00100011,%01100100
db %11100000,%00000010
db %00000010,%00000000
db %00000000,%00000000
db %00000000,%00000000
db %00000000,%00000000
db %00000000,%00000000
db %00000000,%00000000
db %00000000,%00000000
db %00000000,%00000000
db %00000000,%00000000
db %00000000,%00000000
db %00000000,%00000000
db %00000000,%00000000
db %00000000,%00000000
align 256
Computer_Zero_RAM_7x8:
db %00101100,%01101010
db %01001100,%00101011
db %10001101,%01001011
db %10101000,%11000000
db %00101100,%11100000
db %00001000,%00000111
db %00000000,%00000001
db %00000000,%00000000
db %00000000,%00000000
db %00000000,%00000000
db %00000000,%00000000
db %00000000,%00000000
db %00000000,%00000000
db %00000000,%00000000
db %00000000,%00000000
db %00000000,%00000000
Output:
04
38