Re: [Dev-luatex] Luajittex 0.72.0 announcement

On Thu, Jan 10, 2013 at 4:30 PM, minux wrote:

On Thu, Jan 10, 2013 at 11:26 PM, Patrick Gundlach wrote:

...

Luigi,

this looks very promising!!! I've been able to run a simple document with my publisher with it. Great.

Just a question: there seems to be a new bit library included, right? Is this documented anywhere? Is the library itself documented?

It has these functions:

bit = { ["rol"] = "function: builtin#71" ["rshift"] = "function: builtin#69" ["ror"] = "function: builtin#72" ["bswap"] = "function: builtin#67" ["bxor"] = "function: builtin#75" ["bor"] = "function: builtin#74" ["arshift"] = "function: builtin#70" ["bnot"] = "function: builtin#66" ["tobit"] = "function: builtin#65" ["lshift"] = "function: builtin#68" ["tohex"] = "function: builtin#76" ["band"] = "function: builtin#73" }

http://luajit.org/extensions.html

This is the standard bit library of luajit but there is also bit32 Why two bit library ? bit32 is the bit lib of lua5.2, so it helps the programmer You can check bit32 with the following code (from H. Hagen). Please, note that I've not checked that the bit gives the same results -- but I would like to know, of course. print("testing bitwise operations") assert(bit32.band() == bit32.bnot(0)) assert(bit32.btest() == true) assert(bit32.bor() == 0) assert(bit32.bxor() == 0) assert(bit32.band() == bit32.band(0xffffffff)) assert(bit32.band(1,2) == 0) -- out-of-range numbers assert(bit32.band(-1) == 0xffffffff) assert(bit32.band(2^33 - 1) == 0xffffffff) assert(bit32.band(-2^33 - 1) == 0xffffffff) assert(bit32.band(2^33 + 1) == 1) assert(bit32.band(-2^33 + 1) == 1) assert(bit32.band(-2^40) == 0) assert(bit32.band(2^40) == 0) assert(bit32.band(-2^40 - 2) == 0xfffffffe) assert(bit32.band(2^40 - 4) == 0xfffffffc) assert(bit32.lrotate(0, -1) == 0) assert(bit32.lrotate(0, 7) == 0) assert(bit32.lrotate(0x12345678, 4) == 0x23456781) assert(bit32.rrotate(0x12345678, -4) == 0x23456781) assert(bit32.lrotate(0x12345678, -8) == 0x78123456) assert(bit32.rrotate(0x12345678, 8) == 0x78123456) assert(bit32.lrotate(0xaaaaaaaa, 2) == 0xaaaaaaaa) assert(bit32.lrotate(0xaaaaaaaa, -2) == 0xaaaaaaaa) for i = -50, 50 do assert(bit32.lrotate(0x89abcdef, i) == bit32.lrotate(0x89abcdef, i%32)) end assert(bit32.lshift(0x12345678, 4) == 0x23456780) assert(bit32.lshift(0x12345678, 8) == 0x34567800) assert(bit32.lshift(0x12345678, -4) == 0x01234567) assert(bit32.lshift(0x12345678, -8) == 0x00123456) assert(bit32.lshift(0x12345678, 32) == 0) assert(bit32.lshift(0x12345678, -32) == 0) assert(bit32.rshift(0x12345678, 4) == 0x01234567) assert(bit32.rshift(0x12345678, 8) == 0x00123456) assert(bit32.rshift(0x12345678, 32) == 0) assert(bit32.rshift(0x12345678, -32) == 0) assert(bit32.arshift(0x12345678, 0) == 0x12345678) assert(bit32.arshift(0x12345678, 1) == 0x12345678 / 2) assert(bit32.arshift(0x12345678, -1) == 0x12345678 * 2) assert(bit32.arshift(-1, 1) == 0xffffffff) assert(bit32.arshift(-1, 24) == 0xffffffff) assert(bit32.arshift(-1, 32) == 0xffffffff) assert(bit32.arshift(-1, -1) == (-1 * 2) % 2^32) print("+") -- some special cases local c = {0, 1, 2, 3, 10, 0x80000000, 0xaaaaaaaa, 0x55555555, 0xffffffff, 0x7fffffff} for _, b in pairs(c) do assert(bit32.band(b) == b) assert(bit32.band(b, b) == b) assert(bit32.btest(b, b) == (b ~= 0)) assert(bit32.band(b, b, b) == b) assert(bit32.btest(b, b, b) == (b ~= 0)) assert(bit32.band(b, bit32.bnot(b)) == 0) assert(bit32.bor(b, bit32.bnot(b)) == bit32.bnot(0)) assert(bit32.bor(b) == b) assert(bit32.bor(b, b) == b) assert(bit32.bor(b, b, b) == b) assert(bit32.bxor(b) == b) assert(bit32.bxor(b, b) == 0) assert(bit32.bxor(b, 0) == b) assert(bit32.bnot(b) ~= b) assert(bit32.bnot(bit32.bnot(b)) == b) assert(bit32.bnot(b) == 2^32 - 1 - b) assert(bit32.lrotate(b, 32) == b) assert(bit32.rrotate(b, 32) == b) assert(bit32.lshift(bit32.lshift(b, -4), 4) == bit32.band(b, bit32.bnot(0xf))) assert(bit32.rshift(bit32.rshift(b, 4), -4) == bit32.band(b, bit32.bnot(0xf))) for i = -40, 40 do assert(bit32.lshift(b, i) == math.floor((b * 2^i) % 2^32)) end end assert(not pcall(bit32.band, {})) assert(not pcall(bit32.bnot, "a")) assert(not pcall(bit32.lshift, 45)) assert(not pcall(bit32.lshift, 45, print)) assert(not pcall(bit32.rshift, 45, print)) print("+") -- testing extract/replace assert(bit32.extract(0x12345678, 0, 4) == 8) assert(bit32.extract(0x12345678, 4, 4) == 7) assert(bit32.extract(0xa0001111, 28, 4) == 0xa) assert(bit32.extract(0xa0001111, 31, 1) == 1) assert(bit32.extract(0x50000111, 31, 1) == 0) assert(bit32.extract(0xf2345679, 0, 32) == 0xf2345679) assert(not pcall(bit32.extract, 0, -1)) assert(not pcall(bit32.extract, 0, 32)) assert(not pcall(bit32.extract, 0, 0, 33)) assert(not pcall(bit32.extract, 0, 31, 2)) assert(bit32.replace(0x12345678, 5, 28, 4) == 0x52345678) assert(bit32.replace(0x12345678, 0x87654321, 0, 32) == 0x87654321) assert(bit32.replace(0, 1, 2) == 2^2) assert(bit32.replace(0, -1, 4) == 2^4) assert(bit32.replace(-1, 0, 31) == 2^31 - 1) assert(bit32.replace(-1, 0, 1, 2) == 2^32 - 7) print'OK' -- luigi