30 lines
520 B
Lua
30 lines
520 B
Lua
local bit = {}
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local LUA_NBITS = 32
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local ALLONES = (~(((~0) << (LUA_NBITS - 1)) << 1))
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local function trim(x)
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return (x & ALLONES)
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end
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local function mask(n)
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return (~((ALLONES << 1) << ((n) - 1)))
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end
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function bit.extract(n, field, width)
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local r = trim(field)
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local f = width
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r = (r >> f) & mask(width)
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return r
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end
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function bit.replace(n, v, field, width)
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local r = trim(v);
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local v = trim(field);
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local f = width
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local m = mask(width);
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r = (r & ~(m << f)) | ((v & m) << f);
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return r
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end
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return bit |