Making Lua BitOp work with LNUM patch

Hi,

I am writing some Lua code for OpenWRT platform that uses Lua BitOp(http://bitop.luajit.org/).

I am having problem in getting expected result.

1. Initial problem:

On OpenWRT, Lua is applied with LNUM patch that changes the number representation internally. Initially the compilation of Lua BitOp was failing with an error:

"Unknown number type, check LUA_NUMBER_* in luaconf.h"

After some investigation with luaconf.h on native Linux platform and OpenWRT platform, I came to know about LNUM patch and how it adds a different kind of support for double/ints for OpenWRT (http://stackoverflow.com/questions/945731/what-is-the-maximum-value-of-a-number-in-lua#answer-947763).

So I modified bit.c and added

#if defined(LUA_NUMBER_DOUBLE) || defined(LNUM_DOUBLE)

where ever LUA_NUMBER_DOUBLE was "#ifdef"ed in "bit.c"

With this change, the library started compiling for OpenWRT platform and bit.so was generated.

2. Sanity test failure problem:

I transferred bit.so and bittest.lua (a sanity test script provided by the library) to my OpenWRT router(attitude-adjustment, Lua5.1). But after running it, the code fails with the error:

"lua: bit.tobit test failed (got 409089, expected 277312)"

Some more investigation of that script code shows that internally, at one point, bit.so is returning

4294967295 instead of -1(The latter value being returned on the native Linux platform where the tests succeed).

Clearly, it is not converting an unsigned number max to signed number -1 but I am not sure why that is happening (I thought DOUBLE in either case is 8 bytes so that should not be a problem, but I am aware that my understanding is somehow wrong).

3. Another unsuccessful attempt at fixing:

I also tried compiling Lua with LNUM_INT32 enabled and in the bit.c, I enabled LUA_NUMBER_INT instead of code for LUA_NUMBER_DOUBLE. Then I transferred the newly compiled Lua interpreter binary and once again tried to run bittest.lua with it. Even that failed with the same result.

Hopefully somebody has faced this problem before and can help me out.

Thanks.

Methos