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- Subject: Re: native code for bitwise operators in LUA
- From: liam mail <liam.list@...>
- Date: Wed, 2 Nov 2011 20:27:03 +0000
On 2 November 2011 20:24, liam mail <firstname.lastname@example.org> wrote:
> 2011/11/2 Ing. Jan Supuka SBM <email@example.com>:
>> 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]
>> 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.
>> 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 ||
Oh, I forgot to say did you have a Lua Uppercase Accident :)
Lua != LUA