Re: native code for bitwise operators in LUA

[liam mail <liam.list@...>]

2011/11/2 Ing. Jan Supuka SBM <sbmintegral@sbmintegral.sk>:
> In newest LUA 5.2 beta is implemented UNSIGNED INTEGER type and library
> bit32 for bitwise operations.
> BEAUTIFULL !
>
> But I don't like write
>    a = bit32.bor(bit32.band(5,2345),bit32.band(23,7))
> instead of
>    a = 5&2345|23&7
> that's why I rework source codes ( lua-5.2.0-beta.tar.gz [NEW]
> 2011-07-08
>                                http://www.lua.org/work/lua-5.2.0-beta.tar.gz
> )
> to use "native" operators (based on
> http://www.wra1th.plus.com/lua/risclua.html source code) :
>    band &
>    bor     |
>    bxor    ^^
>    lshift <<
>    rshift >>
>    bnot    ~
> and my own logical operators:
>    and &&
>    or      ||
>    not     !
>
> All source code changes are dependent on (luaconfig.h)
> #define GCW_BIT
> /*
> GCW_BIT: Use bit library.
> This extends virtual machine with bitwise operations
> &,|, ^^, ~, <<, >> and provides corresponding events.
> Warning! Makes code non-portable.
> Affects c.lvm, c.lcode, c.lopcodes, c.ltm
> c.llex, c.lparser, h.lcode, h.lopcodes
> h.ltm, h.llex, h.luaconf.
>
> additionally NUM_logical operators ( return numerical (1,0), not boolean
> values )
> !,&&,||
> */
>
> IMPORTANT:   in standart LUA is not possible use boolean (true,false) in
> arithmetical operations,
> but I need it.
> On (lvm.c line:375) is it possible (unremark) allow using booleans only for
> new operators.
> ------------------------------
> Need tests, if all is correct.
> ------------------------------
>
> SOURCE:
> http://sourceforge.net/projects/lualubit/files/
> BASIC TEST ... approximately 5x faster native versus bit32.bxxx operators,
>  more readable LUA source
>
>
>
>
>

Thanks it looks interesting although on first try to compile I get an
error about luaopen_mathx being undefined, is this a private maths
library?* So I have not yet run the speed tests but I would recommend
some changes in both Rio Lua usage and your own.
Such as:
Don't use io operations inside a profile test
Use locals instead of globals
Be nice to Rio Lua and cache bit32.band et al to locals ie local band
= bit32.band

* also a warning is generated for lvm.c:380 suggest parentheses around
&& within ||

Liam