ESP8266 Community Forum

- Wed Dec 10, 2014 11:40 pm #4540 I'd like to hook up a shift register to the ESP-03.
How do I do bitwise operations in LUA?
bit.band(a,b) and bit.lshift(x,n) would be nice. I suppose I can use multiply and divide in a pinch. Far less efficient though.

- Thu Dec 11, 2014 9:06 am #4557 I found an implementation of the bit library written in Lua

http://files.luaforge.net/releases/bit/bit/luabitv0.4

Haven't tried it, but it will be a good start to save some programming, I suspect.

If not, there are other links to check out here:

http://lua-users.org/wiki/BitwiseOperators

Peter

ESP8266 for dummies, LuaLoader and project updates: http://benlo.com/esp8266

- Thu Dec 11, 2014 10:04 am #4561 I have test a bitwise module. it cost about 400bytes ram.
the total ram remain will be below 20k.
worth it?

- Thu Dec 11, 2014 10:33 am #4564

I have test a bitwise module. it cost about 400bytes ram.
the total ram remain will be below 20k.
worth it?

Would it be possible to build this (and other parts of the api) as 'unloadable' functions? Looking at the globals in the interpreter:

Code: Select allmodule:function: 3fff6cb8
require:function: 3fff6d08
pairs:function: 3fff6650
newproxy:function: 3fff6728
package:table: 3fff6858
_G:table: 3fff6020
__index:lightfunction: 40228cc4
ipairs:function: 3fff6598


I can set unneeded ones to nil - gaining some memory.
Would be great if we could do this with api modules too - choose from i2c,pwm,adc,ow,bit....

Thomas