bitsnbobs

bitsnbobs.lua

local bit = require("bit")

local function u8_ToBinaryRepresentation (u8)
  local function AND (x, v)
    local res = bit.band(x, v)
    if res ~= 0 then
      return 1
    else
      return 0
    end
  end

  return table.concat(
    {
      table.concat {
        AND(u8, 0x80);
        AND(u8, 0x40);
        AND(u8, 0x20);
        AND(u8, 0x10);

        AND(u8, 0x08);
        AND(u8, 0x04);
        AND(u8, 0x02);
        AND(u8, 0x01);
      };
    }, " ")
end

local function u32_ToBinaryRepresentation (u32)
  local AND = bit.band
  local RSH = bit.rshift
  local bytes = {
    RSH(AND(u32, 0xff000000), 24);
    RSH(AND(u32, 0x00ff0000), 16);
    RSH(AND(u32, 0x0000ff00), 8);
    AND(    u32, 0x000000ff);
  }
  local binaries = {
    u8_ToBinaryRepresentation(bytes[1]);
    u8_ToBinaryRepresentation(bytes[2]);
    u8_ToBinaryRepresentation(bytes[3]);
    u8_ToBinaryRepresentation(bytes[4]);
  }

  return table.concat(binaries, " ")
end

for i = 0, 31 do
  local v = bit.lshift(1, i)
  print(string.format("1 << %d", i),
        string.format("%s", bit.tohex(v)),
        string.format("%-12d", v),
        u32_ToBinaryRepresentation(v))
end

output.txt

1 << 0  00000001        1               00000000 00000000 00000000 00000001
1 << 1  00000002        2               00000000 00000000 00000000 00000010
1 << 2  00000004        4               00000000 00000000 00000000 00000100
1 << 3  00000008        8               00000000 00000000 00000000 00001000
1 << 4  00000010        16              00000000 00000000 00000000 00010000
1 << 5  00000020        32              00000000 00000000 00000000 00100000
1 << 6  00000040        64              00000000 00000000 00000000 01000000
1 << 7  00000080        128             00000000 00000000 00000000 10000000
1 << 8  00000100        256             00000000 00000000 00000001 00000000
1 << 9  00000200        512             00000000 00000000 00000010 00000000
1 << 10 00000400        1024            00000000 00000000 00000100 00000000
1 << 11 00000800        2048            00000000 00000000 00001000 00000000
1 << 12 00001000        4096            00000000 00000000 00010000 00000000
1 << 13 00002000        8192            00000000 00000000 00100000 00000000
1 << 14 00004000        16384           00000000 00000000 01000000 00000000
1 << 15 00008000        32768           00000000 00000000 10000000 00000000
1 << 16 00010000        65536           00000000 00000001 00000000 00000000
1 << 17 00020000        131072          00000000 00000010 00000000 00000000
1 << 18 00040000        262144          00000000 00000100 00000000 00000000
1 << 19 00080000        524288          00000000 00001000 00000000 00000000
1 << 20 00100000        1048576         00000000 00010000 00000000 00000000
1 << 21 00200000        2097152         00000000 00100000 00000000 00000000
1 << 22 00400000        4194304         00000000 01000000 00000000 00000000
1 << 23 00800000        8388608         00000000 10000000 00000000 00000000
1 << 24 01000000        16777216        00000001 00000000 00000000 00000000
1 << 25 02000000        33554432        00000010 00000000 00000000 00000000
1 << 26 04000000        67108864        00000100 00000000 00000000 00000000
1 << 27 08000000        134217728       00001000 00000000 00000000 00000000
1 << 28 10000000        268435456       00010000 00000000 00000000 00000000
1 << 29 20000000        536870912       00100000 00000000 00000000 00000000
1 << 30 40000000        1073741824      01000000 00000000 00000000 00000000
1 << 31 80000000        -2147483648     10000000 00000000 00000000 00000000