99 lines
1.8 KiB
Lua
99 lines
1.8 KiB
Lua
bit32 = {}
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local N = 32
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local P = 2^N
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function bit32.bnot(x)
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x = x % P
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return P - 1 - x
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end
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function bit32.band(x, y)
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-- Common usecases, they deserve to be optimized
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if y == 0xff then return x % 0x100 end
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if y == 0xffff then return x % 0x10000 end
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if y == 0xffffffff then return x % 0x100000000 end
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x, y = x % P, y % P
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local r = 0
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local p = 1
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for i = 1, N do
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local a, b = x % 2, y % 2
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x, y = math.floor(x / 2), math.floor(y / 2)
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if a + b == 2 then
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r = r + p
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end
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p = 2 * p
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end
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return r
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end
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function bit32.bor(x, y)
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-- Common usecases, they deserve to be optimized
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if y == 0xff then return x - (x%0x100) + 0xff end
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if y == 0xffff then return x - (x%0x10000) + 0xffff end
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if y == 0xffffffff then return 0xffffffff end
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x, y = x % P, y % P
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local r = 0
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local p = 1
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for i = 1, N do
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local a, b = x % 2, y % 2
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x, y = math.floor(x / 2), math.floor(y / 2)
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if a + b >= 1 then
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r = r + p
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end
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p = 2 * p
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end
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return r
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end
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function bit32.bxor(x, y)
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x, y = x % P, y % P
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local r = 0
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local p = 1
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for i = 1, N do
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local a, b = x%2, y%2
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x, y = math.floor(x/2), math.floor(y/2)
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if a + b == 1 then
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r = r + p
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end
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p = 2 * p
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end
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return r
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end
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function bit32.lshift(x, s_amount)
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if math.abs(s_amount) >= N then return 0 end
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x = x % P
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if s_amount < 0 then
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return math.floor(x * (2 ^ s_amount))
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else
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return (x * (2 ^ s_amount)) % P
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end
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end
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function bit32.rshift(x, s_amount)
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if math.abs(s_amount) >= N then return 0 end
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x = x % P
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if s_amount > 0 then
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return math.floor(x * (2 ^ - s_amount))
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else
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return (x * (2 ^ -s_amount)) % P
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end
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end
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function bit32.arshift(x, s_amount)
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if math.abs(s_amount) >= N then return 0 end
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x = x % P
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if s_amount > 0 then
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local add = 0
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if x >= P/2 then
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add = P - 2 ^ (N - s_amount)
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end
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return math.floor(x * (2 ^ -s_amount)) + add
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else
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return (x * (2 ^ -s_amount)) % P
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end
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end
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