July 2002
Intermediate to advanced
320 pages
8h 15m
English
Content preview from Hacker's Delight
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2-17. Multibyte Add, Subtract, Absolute Value
Some applications deal with arrays of short integers (usually bytes or halfwords), and often execution is faster if they are operated on a word at a time. For definiteness, the examples here deal with the case of four 1-byte integers packed into a word, but the techniques are easily adapted to other packings, such as a word containing a 12-bit integer and two 10-bit integers, and so on. These techniques are of greater value on 64-bit machines, because more work is done in parallel.
Addition must be done in a way that blocks the carries from one byte into another. This can be accomplished by the following two-step method:
1. |
Mask out the high-order bit of each byte of each operand and add (there ... |
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.