LibTiff Mailing List
TIFF and LibTiff Mailing List Archive
November 2009
Previous Thread
Next Thread
Previous by Thread
Next by Thread
Previous by Date
Next by Date
Contact
The TIFF Mailing List Homepage
This list is run by Frank Warmerdam
Archive maintained by AWare Systems
Thread
2009.11.04 08:45 "Re: Tiffcrop test suite and logluv issues", by Juergen Buchmueller
On Tue, 3 Nov 2009 12:46:26 -0800 Daniel McCoy <mccoy@pixar.com> wrote: > From Toby Thain <toby@telegraphics.com.au>, Tue, Nov 03, 2009 at 07:16:07AM -0500: > > > > > > Alternatively one could write: > > > tp[i] = 65536 * bp[0] + 256 * bp[1] + bp[2]; > > > > > > Compilers today transform the power-of-two multiplications into rather > > > effective code (read: shift lefts) and it doesn't require parens. > > > > This adds to the cognitive load for humans. A shift shows the intent > > more clearly. > > True. > One way of reducing the cognitive load in the multiply version > is to use hex constants: > > tp[i] = 0x10000 * bp[0] + 0x100 * bp[1] + bp[2]; > > which show the intent more clearly than the decimal constants. I don't agree, but that may be due to me recognizing powers of two in decimal just as well as in hex .. at least up to 2^20. Here's a suggestion for the ambitious commenter: #define SHL24(x) 0x1000000*(x) #define SHL16(x) 0x10000*(x) #define SHL8(x) 0x100*(x) tp[i] = SHL16(bp[0]) + SHL8(bp[1]) + bp[2]; ;-) Juergen