bitwise shifts gone?

Mark Wieder ahsoftware at sonic.net
Sat Jun 30 11:00:31 EDT 2018


On 06/30/2018 03:50 AM, hh via use-livecode wrote:
> Mark,
> 
> obviously you ask relating to Bob's IPv4 sort problem.

A perceptive observation, as always.

> 
> But when optimising (for speed) the connected formula
> 
> (1) a + b * 2^8 + c * 2^16 + d * 2^32
> 
> using the constants is slightly faster:
> 
> (2) a + b * 256 + c * 65536 + d * 16777216

Would bitOr operators increase the speed over additions?

> 
> Why is the engine not handling the internal bitshifts easier with (1)?

Indeed. I'm not too upset about the loss of the bitshift operators other 
than the lack of backward compatibility, but I'm surprised by their 
demise. In terms of minimal use of microprocessor cycles I'd expect that 
the fastest would be

a || (b << 8) || (c << 16) || (d << 32)

-- 
  Mark Wieder
  ahsoftware at gmail.com




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