Compute 116 000 digits of e using Steve Wozniak algorithm from Byte

compute_e.js

// see: https://archive.org/stream/byte-magazine-1981-06/1981_06_BYTE_06-06_Operating_Systems#page/n393/mode/2up


function word(x) { return (x & 0xffff); }

function wordstr(x) { return ('0000000000000000' + x.toString(16)).slice(-4); }

function divide(dividendWords, divisorWord, prevRest) {
    var BITS_PER_WORD = 16;
    var MAX_DIVISOR = (1 << 16) - 1;

    if (divisorWord > MAX_DIVISOR)
        throw new Error('divisor too large.');

    var d = divisorWord;

    var hi = +(prevRest || 0);
    var lo = 0;

    for (var w = 0, len = dividendWords.length; w < len; w++) {
        lo = dividendWords[w];

        // divide [hi|lo] by d
        for (var i = 0; i < BITS_PER_WORD; i++) {
            // hi <- MSB lo <- lo
            var loMSB = (lo & (1 << 15)) >> 15;
            hi = word(hi << 1 | loMSB);

            var r = 0;
            if (hi >= d) {
                hi -= d;
                r = 1;
            }

            // lo <- bit of result
            lo = word(lo << 1) | r;
        }

        dividendWords[w] = lo;
    }

    // return rest
    return hi;
}

function print10(words, digits) {
    var str = '2.';

    var mult100 = [], carry100 = [];
    for (var i = 0; i < 256; i++) {
        var w = (i*100);

        mult100[i] = w & 0x00ff;
        carry100[i] = (w & 0xff00) >> 8;
    }

    var carry = 0;
    var mult100Byte = function(b) {
        var carryB = carry100[b];
        b = mult100[b] + carry;

        carry = ((b & 0xff00) >> 8) + carryB;
        b = (b & 0x00ff);

        return b;
    };

    for (var i = 0; i < digits; i+=2) {
        // multiply words by 100

        for (var j = words.length-1; j >= 0; j--) {
            var lo = mult100Byte(words[j] & 0x00ff);
            var hi = mult100Byte((words[j] & 0xff00) >> 8);
            words[j] = (hi << 8) | lo;
        }

        var digit0 = (carry % 10);
        var digit1 = Math.floor(carry / 10) % 10;
        str += String(digit1) + String(digit0);
    }

    console.log(str);
}

function calculateE(words, N) {
    for (var n = N; n >= 2; n--) {
        // console.log('[' + ((n*100/N)|0) + ']')
        divide(words, n, 1);
    }
}

function zeroArray(n) {
    var a = [];

    for (var i = 0; i < n; i++)
        a[i] = 0;

    return a;
}

var dividentFract = zeroArray(48*1024);
calculateE(dividentFract, 30000);

// prints 116 000 digits of e after . 
print10(dividentFract, 116000);