Re: [ANN] Lua 5.3.0 (work2) now available

[Tim Hill <drtimhill@...>]

On Mar 26, 2014, at 5:01 AM, Roberto Ierusalimschy <roberto@inf.puc-rio.br> wrote:

>> As a side note, arithmetic shift is NOT equivalent to division by a power of two as the two functions have different rounding properties for negative dividends. Assuming you are using a C compiler that *does* do arithmetic shifts with signed operands, the following code will simulate integer division using shifts only:
> 
> This is in C. In Lua both are equivalent; integer division in Lua rounds
> toward minus infinity, like an arithmetic shift.
> 
> -- Roberto
> 

Interesting, and a bit worrying. Is there any reason for this? I suspect this is going to be a source of confusion for some people porting code from C, as this can introduce subtle off-by-one bugs in algorithms.

—Tim