8153b68d46
* default to LuaJIT when available * add LuaBitOp for efficient bitwise operations in Lua * make lib_bits use LuaBitOp if present * add LuaBitOp licence notice * fix CMake to work with LuaJIT/LuaBitOp, enforce C99
74 lines
1.6 KiB
Lua
74 lines
1.6 KiB
Lua
--[[
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This file is part of Ice Lua Components.
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Ice Lua Components is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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Ice Lua Components is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with Ice Lua Components. If not, see <http://www.gnu.org/licenses/>.
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]]
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function bit_unsign(a,m)
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m = math.pow(2,m)
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local v = (a % m)
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if v < 0 then
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v = v + m
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end
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return v
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end
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function bit_xor(a,b)
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local shift = 1
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local v = 0
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while a > 0 and b > 0 do
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if ((a % 2) ~= 0) ~= ((b % 2) ~= 0) then
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v = v + shift
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end
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shift = shift * 2
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a = math.floor(a/2)
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b = math.floor(b/2)
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end
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return v + a*shift + b*shift
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end
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function bit_or(a,b)
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local shift = 1
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local v = 0
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while a > 0 and b > 0 do
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if ((a % 2) ~= 0) or ((b % 2) ~= 0) then
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v = v + shift
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end
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shift = shift * 2
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a = math.floor(a/2)
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b = math.floor(b/2)
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end
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return v + a*shift + b*shift
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end
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function bit_and(a,b)
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local shift = 1
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local v = 0
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while a > 0 and b > 0 do
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if ((a % 2) ~= 0) and ((b % 2) ~= 0) then
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v = v + shift
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end
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shift = shift * 2
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a = math.floor(a/2)
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b = math.floor(b/2)
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end
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return v
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end
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if bit then
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bit_xor = bit.bxor
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bit_or = bit.bor
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bit_and = bit.band
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end
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