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define EOF = 0xffff;
define BUF_SIZE = 0x4000;
define MEM_SIZE = 0x8000; // has to be 2^x
define MEM_MAX_PTR = MEM_SIZE - 1;
global buf[BUF_SIZE] = 0;
global pc = 0;
global mem[MEM_SIZE] = 0;
global mem_ptr = 0;
main() {
if drain() |> ensure_match
return error("[] don't match");
loop {
if ([buf + pc] == 0)
return;
getop() |> exec;
}
}
drain() {
local p = buf;
loop {
red p;
if ([p] == EOF | [p] == '\n') {
[p] = 0;
return buf;
}
p++;
}
}
ensure_match(p) {
local matching = 0;
loop {
if ([p] == 0)
return matching;
if ([p] == ']' & matching == 0)
return 1;
matching = matching + ([p] == '[') - ([p] == ']');
p++;
}
}
error(msg) {
loop {
if ([msg] == 0) {
wrt '\n';
return;
}
wrt [msg++];
}
}
getop() => [buf + pc++];
exec(op)
if (op == '<') mem_ptr = (mem_ptr - 1) & MEM_MAX_PTR;
else if (op == '>') mem_ptr = (mem_ptr + 1) & MEM_MAX_PTR;
else if (op == '+') [mem + mem_ptr] = ([mem + mem_ptr] + 1) & 0xff;
else if (op == '-') [mem + mem_ptr] = ([mem + mem_ptr] - 1) & 0xff;
else if (op == '.') wrt [mem + mem_ptr];
else if (op == ',') red mem + mem_ptr;
else if (op == '[') => zjmpfwd();
else if (op == ']') => nzjmpbckwd();
zjmpfwd() {
local matching = 1;
if ([mem + mem_ptr] == 0) loop {
matching = matching + ([buf + pc] == '[') - ([buf + pc] == ']');
pc++;
if (matching == 0)
return;
}
}
nzjmpbckwd() {
local matching = 0;
if ([mem + mem_ptr] != 0) loop {
pc--;
matching = matching + ([buf + pc] == ']') - ([buf + pc] == '[');
if (matching == 0)
return pc++;
}
}
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