Execute Computer/Zero: Difference between revisions
Added XPL0 example.
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for (prog in progs) interp.call(prog)</syntaxhighlight>
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=={{header|XPL0}}==
Some simplifying assumptions are made. Literal addresses are used instead
of labels. The STP instruction merely stops (and displays the
accumulator) rather than allowing the program to continue after a key is
struck. This prevents the Prisoner's Dilemma from running as intended.
<syntaxhighlight lang "XPL0">def NOP=0, LDA=1, STA=2, ADD=3, SUB=4, BRZ=5, JMP=6, STP=7;
char Mem(32);
string 0;
proc Load(Prog); \Load program into memory
char Prog;
int PC, I, Ch, Hash;
func GetNum; \Return value of number
int Num;
[while Ch <= $20 do
[Ch:= Prog(I); I:= I+1];
Num:= 0;
while Ch>=^0 and Ch<=^9 do
[Num:= Num*10 + Ch - ^0;
Ch:= Prog(I); I:= I+1;
];
return Num;
];
[PC:= 0; I:= 0;
repeat repeat Ch:= Prog(I); I:= I+1; until Ch > $20;
if Ch>=^0 and Ch<=^9 then
Mem(PC):= GetNum
else [Hash:= 0;
while Ch >= ^A do
[Hash:= Hash + Ch;
Ch:= Prog(I); I:= I+1;
];
case Hash of
^N+^O+^P: Mem(PC):= NOP<<5;
^L+^D+^A: Mem(PC):= LDA<<5 + GetNum;
^S+^T+^A: Mem(PC):= STA<<5 + GetNum;
^A+^D+^D: Mem(PC):= ADD<<5 + GetNum;
^S+^U+^B: Mem(PC):= SUB<<5 + GetNum;
^B+^R+^Z: Mem(PC):= BRZ<<5 + GetNum;
^J+^M+^P: Mem(PC):= JMP<<5 + GetNum;
^S+^T+^P: Mem(PC):= STP<<5
other [Text(0, "Bad opcode at "); IntOut(0, PC); exit];
];
PC:= PC+1;
until Ch = 0;
];
proc Run(Prog); \Load and run a program
int Prog, PC, Acc, Instr, Addr;
[Load(Prog);
PC:= 0; Acc:= 0;
loop [Instr:= Mem(PC) >> 5;
Addr:= Mem(PC) & $1F;
PC:= PC+1;
case Instr of
LDA: Acc:= Mem(Addr);
STA: Mem(Addr):= Acc;
ADD: Acc:= Acc + Mem(Addr) & $FF;
SUB: Acc:= Acc - Mem(Addr) & $FF;
BRZ: if Acc = 0 then PC:= Addr;
JMP: PC:= Addr;
STP: quit
other []; \NOP
if PC > 31 then quit;
];
IntOut(0, Acc); CrLf(0);
];
int Progs, N;
[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 0 0 0 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 N:= 0 to 4 do Run(Progs(N));
]</syntaxhighlight>
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