Back in time it was known for being a fast way to multiply and divide by powers of 2. This hasn't been true for a long time now, and in the rare cases it is, most optimizing compilers will bitwise shift where in your source code you divide or multiply.
Shifting is still faster than multiplication--a shift is a 1-cycle operation, multiplication typically 3 cycles. Division is somewhere in the region of a dozen cycles or more. (Also, division is one of the assembly operations whose time is data-dependent). So it's faster to replace a multiplication with a single shift (but not multiple shifts), and to replace division with shifts or even multiplies--there's a fast division replacement that replaces a division by a small constant with a multiply-hi and shift.
Will compilers replace multiplies and divides with shifts? Kind of. If you multiply a value with a constant (after inlining/constant propagation/etc.) that's a power of two, or if you multiply it with an expression 1 << var, then that will be converted to a shift.
For division, it's even more complicated because shifts and division by power of 2 are not equivalent if the type is signed: -1 / 2 is 0 but -1 >> 1 is -1, so the transform is not legal unless the compiler can find out either a) the value is never negative or b) the division is exact.
Additionally if you're ever working directly with hardware, writing drivers, or firmware, bit-shift operations are often the best (and most common) way to get stuff done.
The problem with bitshifting is that it's just a special case of multiplication and division. So if you want your hardware utilized, you don't scale bitshifts, that'd be largely useless. You scale multiplication and division, and this is what modern hardware does.
Bitshifting is very simple in terms of hardware, but scale beats simplicity.
ie, embedded systems and microcontrollers - which is where binary formats and bitwise operations still rule out of necessity (limited processing power, precious cycle counts per operation, limited memory and storage, etc).
I highly doubt your average web or app developer will ever need to use bitwise operations. They're harder to read and understand quickly, and none of the limitations that make bitwise operations attractive exist on devices with gigabytes of ram and terabytes of storage.
Disagree. Never had problem with bits. Also it is one of the basics of general computing so it would not hurt to know about the subject.
Something like:
(some_var & 0x003ff000) >> 12;
_displayControl &= ~DISPLAY_ON;
It's a lot easier to understand:
display.disable();
I read about a lot of things that are not immediately useful for me. Still somehow it falls into nooks and crannies of my brain and helps me to solve various problem when / if need arises. I do not even remember the exact things but general understanding of what is available and how does it functions approximately. If I need details Google does the rest.
>"It's a lot easier to understand:
display.disable();"
What people are saying to you: "You say bitshifting is complex, so if I say bitshifting is simple, it means I'm smarter than you"
To BulgarianIdiot: This is quite a conclusion.
If you're writing a high-performance server or a game engine, you need to understand the topology of computers. Network performance and protocols, disk, memory and cache architecture. But you still don't need to understand every machine code on the CPU.
We're risking falling into the trap of "more is more" like a chemistry teacher that is adamant that you need to absolutely understand covalent, ionic and so on bonds, because everything around you chemistry, including you. I mean how would you find a job as an accountant and start a family without understanding chemistry?
Keep in mind "The Daily WTF" is widely suspected to be making up most of its articles.