Brainfuck interpretter written in Javascript

bf.js

// fmb = F**K My Brain
// ins = instructions string
// oup = terminal output callback function
// inp = terminal input callback function
function fmb(ins, oup, inp) {
    var m = [], dp = 0, ip = 0, 
        il = ins.length, scp = {},
        op, mdp;
    
    for(; ip < il; ip++) {
        op = ins[ip];
        if (op == '[') m.push(ip);
        if (op == ']') {
            scp[ip] = m.pop();
            scp[scp[ip]] = ip + 1;
        }
    }
    
    for(ip = 0, m = []; ip < il;) {
        op = ins[ip];
        dp += (op == '>' && 1) || (op == '<' && -1) || 0;
        mdp = m[dp];
        mdp = (op == ',' && inp && inp()) || 
              (mdp == 128 && -128) || 
              (mdp == -129 && 127) || 
              mdp || 0;
        mdp += (op == '+' && 1) || (op == '-' && -1) || 0;
        ip = (op == '[' && !mdp && scp[ip]) || 
             (op == ']' && scp[ip]) || 
             (ip + 1);
        if (op == '.' && oup) oup(mdp);
        m[dp] = mdp;
    }
  
    return [m, dp];
}
 
function fmb(r,f,n){for(var o,p,t=[],u=0,e=0,h=r.length,a={};e<h;e++)'['==(o = r[e])&&t.push(e),']'==o&&(a[e]=t.pop(),a[a[e]]=-~e);for(e=0,t=[];e<h;)p=t[u+=('>'==(o=r[e])?1:'<'==o&&-1)||0],p=','==o&&n&&n()||128==p&&-128||-129==p&&127||p||0,p+=('+'==o?1:'-'==o&&~0)||0,e='['==o&&!p&&a[e]||']'==o&&a[e]||-~e,'.'==o&&f&&f(p),t[u]=p;return[t,u]}
 
 
var code = '-[------->+<]>-.-[->+++++<]>++.+++++++..+++.[--->+<]>-----.--[->++++<]>-.--------.+++.------.--------.';
var output = '';
fmb(code, function (v) {
    output += String.fromCharCode(v);
});
console.log(output);