Yes, but the idea is that you do this in assembly. It was a common trick because it saved a register and (at worst) it ran in the same number of cycles.
JavaScript, by nature, stores all numbers as double-precision IEEE 754 floating point numbers. The 52 bits of the fractional portion is used to store integers. This results in 'maximum safe integer' of 2^53 - 1. Further complicating things is that JavaScript's bitwise operators only deal with the lowest 32 bits of JavaScript's 54-bit integers. So the bitwise approach will not work on big integers in JavaScript.
This is a rather beautiful "bit" of problem solving :)
It will work for both integers and floating points, positive and negative, and there is no issue with overflow. If someone can figure this out on their own, I think that's quite impressive. Most of us just know it from having seen it before though.
That's true. My initial solution to it was using addition/subtraction and once I got the concept of diffs, I was able to deduce a solution using bit manipulation.
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Bitwise operators for the win.
The swap with bitwise operators will be the fastest at the hardware level. :)
Yes. Whenever you can achieve something using bitwise operations I always prefer that.
Rather disappointingly, in most modern hardware it's the one with the temp variable that is fastest.
Depending on the architecture and compiler, they end up using three registers to do a swap under the hood I think.
Yes, but the idea is that you do this in assembly. It was a common trick because it saved a register and (at worst) it ran in the same number of cycles.
When I started going through the comments, I was actually thinking "what about bitwise xor?" And sure enough, here it is.
^,^JavaScript, by nature, stores all numbers as double-precision IEEE 754 floating point numbers. The 52 bits of the fractional portion is used to store integers. This results in 'maximum safe integer' of 2^53 - 1. Further complicating things is that JavaScript's bitwise operators only deal with the lowest 32 bits of JavaScript's 54-bit integers. So the bitwise approach will not work on big integers in JavaScript.
I guess BigInt new primitive proposal will do the trick :)
This is a rather beautiful "bit" of problem solving :)
It will work for both integers and floating points, positive and negative, and there is no issue with overflow. If someone can figure this out on their own, I think that's quite impressive. Most of us just know it from having seen it before though.
That's true. My initial solution to it was using addition/subtraction and once I got the concept of diffs, I was able to deduce a solution using bit manipulation.