Pure Lua Mersenne Twister

--[[
    `mt` : mersenne twisted pseudorandom number array
    `index` : index of the current `mt` position
    others : indexing global functions for faster performance
]]
local mt, index, band, bor, bxor, lshift, rshift = {}, 0, bit.band, bit.bor, bit.bxor, bit.lshift, bit.rshift

--[[
    initializes `mt` with custom seed or current time
]]
local init_rand = function(s)
    if s == nil then
        s = os.time()
    end
    mt[0] = band(s, 0xffffffff)
    for index = 1, 623 do
        mt[index] = band(0x6c078965 * bxor(mt[index - 1], rshift(mt[index - 1], 30)) + index, 0xffffffff)
    end
end

--[[
    extracts random number from `mt` with tampering
]]
local rand = function()
    local matrix, y = {0, 0x9908b0df}
    if index == 0 then
        init_rand()
        for i = 0, 623 do
            y = bor(band(mt[i], 0x80000000), band(mt[(i + 1) % 624], 0x7ffffff))
            mt[i] = bxor(mt[(i + 397) % 624], rshift(y, 1), matrix[band(y, 1) + 1])
        end
    end
    index = (index + 1) % 624
    y = mt[index]

    --[[ tampering ]]
    y = bxor(y, rshift(y, 11))
    y = band(bxor(y, lshift(y, 7), 0x9d2c5680))
    y = band(bxor(y, lshift(y, 15), 0xefc60000))
    y = bxor(y, rshift(y, 18))

    return y % 0xffffffff
end

for _ = 1, 10000000 do
    rand()
end