Merge pull request #799 from Guldoman/bit32_polyfill
Improve bit32 polyfill
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commit
3b3e41c095
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@ -11,20 +11,26 @@ local function mask(n)
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return (~((ALLONES << 1) << ((n) - 1)))
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end
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local function check_args(field, width)
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assert(field >= 0, "field cannot be negative")
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assert(width > 0, "width must be positive")
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assert(field + width < LUA_NBITS and field + width >= 0,
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"trying to access non-existent bits")
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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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local w = width or 1
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check_args(field, w)
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local m = trim(n)
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return m >> field & mask(w)
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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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local w = width or 1
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check_args(field, w)
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local m = trim(n)
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local x = v & mask(width);
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return m & ~(mask(w) << field) | (x << field)
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end
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return bit
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@ -32,3 +32,5 @@ end }
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table.pack = table.pack or pack or function(...) return {...} end
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table.unpack = table.unpack or unpack
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bit32 = bit32 or require "core.bit"
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@ -1,6 +1,5 @@
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local syntax = require "core.syntax"
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local common = require "core.common"
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local bit32 = require "core.bit"
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local tokenizer = {}
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