changeset
compile: Update copy of minichunkspy.lua (new release)
Thu, 27 May 2010 03:58:27 +0100
- author
- Matthew Wild <mwild1@gmail.com>
- date
- Thu, 27 May 2010 03:58:27 +0100
- changeset 57
- db9b079c1d33
- parent 56
- 791c9d8b750c
- child 58
- 17121881cbf7
compile: Update copy of minichunkspy.lua (new release)
| compile/minichunkspy.lua | file | annotate | diff | comparison | revisions |
--- a/compile/minichunkspy.lua Thu May 27 03:57:30 2010 +0100 +++ b/compile/minichunkspy.lua Thu May 27 03:58:27 2010 +0100 @@ -9,23 +9,35 @@ -- chunk = minichunkspy.assemble(disassembled_chunk) -- assert(minichunkspy.validate(<function or chunk>)) -- --- Tested on little-endian 32 bit platforms. Modify --- the Size_t type to be a 64 bit integer to make it work --- for 64 bit systems, and set BIG_ENDIAN = true for --- big-endian systems. +-- Tested on little-endian 32 and 64 bit platforms. local string, table, math = string, table, math local ipairs, setmetatable, type, assert = ipairs, setmetatable, type, assert local _ = __END_OF_GLOBALS__ local string_char, string_byte, string_sub = string.char, string.byte, string.sub +local math_frexp, math_ldexp, math_abs = math.frexp, math.ldexp, math.abs local table_concat = table.concat -local math_abs, math_ldexp, math_frexp = math.abs, math.ldexp, math.frexp local Inf = math.huge -local Nan = Inf - Inf +local NaN = Inf - Inf + +local BIG_ENDIAN = false +local SIZEOF_SIZE_T = 4 +local SIZEOF_INT = 4 +local SIZEOF_NUMBER = 8 + +local save_stack = {} -local BIG_ENDIAN = false --twiddle this for your platform. +local function save() + save_stack[#save_stack+1] + = {BIG_ENDIAN, SIZEOF_SIZE_T, SIZEOF_INT, SIZEOF_NUMBER} +end +local function restore () + BIG_ENDIAN, SIZEOF_SIZE_T, SIZEOF_INT, SIZEOF_NUMBER + = unpack(save_stack[#save_stack]) + save_stack[#save_stack] = nil +end -local function construct (class, ...) - return class.new(class, ...) +local function construct (class, self) + return class.new(class, self) end local mt_memo = {} @@ -89,19 +101,152 @@ end } -local int32 = uint32{ - unpack = function (self, bytes, ix) - local val, ix = uint32:unpack(bytes, ix) - return val < 2^32 and val or (val - 2^31), ix - end +local uint64 = Field{ + unpack = + function (self, bytes, ix) + local a = uint32:unpack(bytes, ix) + local b = uint32:unpack(bytes, ix+4) + if BIG_ENDIAN then a,b = b,a end + return a + b*2^32, ix+8 + end, + pack = + function (self, val) + assert(type(val) == "number", + "unexpected value type to pack as an uint64") + local a = val % 2^32 + local b = (val - a) / 2^32 + if BIG_ENDIAN then a,b = b,a end + return uint32:pack(a) .. uint32:pack(b) + end +} + +local function explode_double(bytes, ix) + local a = uint32:unpack(bytes, ix) + local b = uint32:unpack(bytes, ix+4) + if BIG_ENDIAN then a,b = b,a end --XXX: ARM mixed-endian + + local sig_hi = b % 2^20 + local sig_lo = a + local significand = sig_lo + sig_hi*2^32 + + b = (b - sig_hi) / 2^20 + + local biased_exp = b % 2^11 + local sign = b <= biased_exp and 1 or -1 + + --print(sign, significand, biased_exp, "explode") + return sign, biased_exp, significand +end + +local function implode_double(sign, biased_exp, significand) + --print(sign, significand, biased_exp, "implode") + local sig_lo = significand % 2^32 + local sig_hi = (significand - sig_lo) / 2^32 + + local a = sig_lo + local b = ((sign < 0 and 2^11 or 0) + biased_exp)*2^20 + sig_hi + + if BIG_ENDIAN then a,b = b,a end --XXX: ARM mixed-endian + return uint32.pack(nil, a) .. uint32.pack(nil, b) +end + +local function math_sign(x) + if x ~= x then return x end --sign of NaN is NaN + if x == 0 then x = 1/x end --extract sign of zero + return x > 0 and 1 or -1 +end + +local SMALLEST_SUBNORMAL = math_ldexp(1, -1022 - 52) +local SMALLEST_NORMAL = SMALLEST_SUBNORMAL * 2^52 +local LARGEST_SUBNORMAL = math_ldexp(2^52 - 1, -1022 - 52) +local LARGEST_NORMAL = math_ldexp(2^53 - 1, 1023 - 52) +assert(SMALLEST_SUBNORMAL ~= 0.0 and SMALLEST_SUBNORMAL / 2 == 0.0) +assert(LARGEST_NORMAL ~= Inf) +assert(LARGEST_NORMAL * 2 == Inf) + +local double = Field{ + unpack = + function (self, bytes, ix) + local sign, biased_exp, significand = explode_double(bytes, ix) + + local val + if biased_exp == 0 then --subnormal + val = math_ldexp(significand, -1022 - 52) + elseif biased_exp == 2047 then + val = significand == 0 and Inf or NaN --XXX: loses NaN mantissa + else --normal + val = math_ldexp(2^52 + significand, biased_exp - 1023 - 52) + end + val = sign*val + return val, ix+8 + end, + + pack = + function (self, val) + if val ~= val then + return implode_double(1,2047,2^52-1) --XXX: loses NaN mantissa + end + + local sign = math_sign(val) + val = math_abs(val) + + if val == Inf then return implode_double(sign, 2047, 0) end + if val == 0 then return implode_double(sign, 0, 0) end + + local biased_exp, significand + + if val <= LARGEST_SUBNORMAL then + biased_exp = 0 + significand = val / SMALLEST_SUBNORMAL + else + local frac, exp = math_frexp(val) + significand = (2*frac - 1)*2^52 + biased_exp = exp + 1022 + end + return implode_double(sign, biased_exp, significand) + end } local Byte = uint8 -local Size_t = uint32 -local Integer = int32 + +local IntegralTypes = { + [4] = uint32, + [8] = uint64 +} + +local FloatTypes = { + [4] = float, + [8] = double +} + +local Size_t = Field{ + unpack = function (self, bytes, ix) + return IntegralTypes[SIZEOF_SIZE_T]:unpack(bytes, ix) + end, + pack = function (self, val) + return IntegralTypes[SIZEOF_SIZE_T]:pack(val) + end, +} + +local Integer = Field{ + unpack = function (self, bytes, ix) + return IntegralTypes[SIZEOF_INT]:unpack(bytes, ix) + end, + pack = function (self, val) + return IntegralTypes[SIZEOF_INT]:pack(val) + end, +} + +local Number = Field{ + unpack = function (self, bytes, ix) + return FloatTypes[SIZEOF_NUMBER]:unpack(bytes, ix) + end, + pack = function (self, val) + return FloatTypes[SIZEOF_NUMBER]:pack(val) + end, +} -- Opaque types: -local Number = char(8) local Insn = char(4) local Struct = Field{ @@ -177,7 +322,7 @@ local String = Field{ unpack = function (self, bytes, ix) - local len, ix = Integer:unpack(bytes, ix) + local len, ix = Size_t:unpack(bytes, ix) local val = nil if len > 0 then -- len includes trailing nul byte; ignore it @@ -191,9 +336,9 @@ assert(type(val) == "nil" or type(val) == "string", "unexpected value type to pack as a String") if val == nil then - return Integer:pack(0) + return Size_t:pack(0) end - return Integer:pack(#val+1) .. val .. "\000" + return Size_t:pack(#val+1) .. val .. "\000" end } @@ -222,6 +367,9 @@ local field = ConstantTypes[t] assert(field, "unknown constant type "..t.." to unpack") local v, ix = field:unpack(bytes, ix) + if t == 3 then + assert(type(v) == "number") + end return { type = t, value = v @@ -259,9 +407,46 @@ "missed the function prototype list") Function[10].type = Function -local Chunk = Struct{ - ChunkHeader{name = "header"}, - Function{name = "body"} +local Chunk = Field{ + unpack = + function (self, bytes, ix) + local chunk = {} + local header, ix = ChunkHeader:unpack(bytes, ix) + assert(header.signature == "\027Lua", "signature check failed") + assert(header.version == 81, "version mismatch") + assert(header.format == 0, "format mismatch") + assert(header.endianness == 0 or + header.endianness == 1, "endianness mismatch") + assert(IntegralTypes[header.sizeof_int], "int size unsupported") + assert(IntegralTypes[header.sizeof_size_t], "size_t size unsupported") + assert(header.sizeof_insn == 4, "insn size unsupported") + assert(FloatTypes[header.sizeof_Number], "number size unsupported") + assert(header.integral_flag == 0, "integral flag mismatch; only floats supported") + + save() + BIG_ENDIAN = header.endianness == 0 + SIZEOF_SIZE_T = header.sizeof_size_t + SIZEOF_INT = header.sizeof_int + SIZEOF_NUMBER = header.sizeof_Number + chunk.header = header + chunk.body, ix = Function:unpack(bytes, ix) + restore() + return chunk, ix + end, + + pack = + function (self, val) + local data + save() + local header = val.header + BIG_ENDIAN = header.endianness == 0 + SIZEOF_SIZE_T = header.sizeof_size_t + SIZEOF_INT = header.sizeof_int + SIZEOF_NUMBER = header.sizeof_Number + data = ChunkHeader:pack(val.header) .. Function:pack(val.body) + restore() + return data + end } local function validate(chunk)
