I still write code for systems that do not have floating point support in hardware. In these systems you need bit-shifting for nearly all your arithmetic. Also you need shifts to generate hashes. Polynomial arithmetic (CRC, Reed-Solomon Codes are the mainstream applications) or uses shifts as well. However, shifts are just used because they are … Read more
Endianness only matters for layout of data in memory. As soon as data is loaded by the processor to be operated on, endianness is completely irrelevent. Shifts, bitwise operations, and so on perform as you would expect (data logically laid out as low-order bit to high) regardless of endianness.
When you write 1 << n You shift the bit combination 000000001 for n times left and thus put n into the exponent of 2: 2^n So 1 << 10 Really is 1024 For a list of say 5 items your for will cycle 32 times.
System.out.println(Integer.toBinaryString(2 << 11)); Shifts binary 2(10) by 11 times to the left. Hence: 1000000000000 System.out.println(Integer.toBinaryString(2 << 22)); Shifts binary 2(10) by 22 times to the left. Hence : 100000000000000000000000 System.out.println(Integer.toBinaryString(2 << 33)); Now, int is of 4 bytes,hence 32 bits. So when you do shift by 33, it’s equivalent to shift by 1. Hence : … Read more
This seems to be because multiplication of small numbers is optimized in CPython 3.5, in a way that left shifts by small numbers are not. Positive left shifts always create a larger integer object to store the result, as part of the calculation, while for multiplications of the sort you used in your test, a … Read more
The number 4946144450195624 fits 64 bits, and its binary representation is: 10001100100100111110111111110111101100011000010101000 The program decodes a character for every 5-bits group, from right to left 00100|01100|10010|01111|10111|11111|01111|01100|01100|00101|01000 d | l | r | o | w | | o | l | l | e | h 5-bit codification For 5 bits, it is possible to … Read more
When shifting left, there is no difference between arithmetic and logical shift. When shifting right, the type of shift depends on the type of the value being shifted. (As background for those readers unfamiliar with the difference, a “logical” right shift by 1 bit shifts all the bits to the right and fills in the … Read more
It doesn’t just convert non-Numbers to Number, it converts them to Numbers that can be expressed as 32-bit unsigned ints. Although JavaScript’s Numbers are double-precision floats(*), the bitwise operators (<<, >>, &, | and ~) are defined in terms of operations on 32-bit integers. Doing a bitwise operation converts the number to a 32-bit signed … Read more
The line: while( a[ 0xFULL?’\0′:-1:>>>=a<:!!0X.1P1 ] ) contains the digraphs :> and <:, which translate to ] and [ respectively, so it’s equivalent to: while( a[ 0xFULL?’\0′:-1 ] >>= a[ !!0X.1P1 ] ) The literal 0xFULL is the same as 0xF (which is hex for 15); the ULL just specifies that it’s an unsigned long … Read more
Short answer: Not likely. Long answer: Your compiler has an optimizer in it that knows how to multiply as quickly as your target processor architecture is capable. Your best bet is to tell the compiler your intent clearly (i.e. i*2 rather than i << 1) and let it decide what the fastest assembly/machine code sequence … Read more