This is caused due to a combination of an undefined behaviour in C and the fact that code generated for IA-32 processors has a 5 bit mask applied on the shift count. This means that on IA-32 processors, the range of a shift count is 0-31 only. 1 From The C programming language 2 The … 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
Right shift of a negative signed number has implementation-defined behaviour. If your 8 bits are meant to represent a signed 8 bit value (as you’re talking about a “signed 32 bit integer” before switching to 8 bit examples) then you have a negative number. Shifting it right may fill “empty” bits with the original MSB … 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 bit shifting operators do exactly what their name implies. They shift bits. Here’s a brief (or not-so-brief) introduction to the different shift operators. The Operators >> is the arithmetic (or signed) right shift operator. >>> is the logical (or unsigned) right shift operator. << is the left shift operator, and meets the needs of … Read more
The following only assumes 2’s complement with at least 16 bits: int mask = ~0x7FFF; return !(x&mask)|!(~x&mask); That uses a 15-bit constant; if that is too big, you can construct it from three smaller constants, but that will push it over the 8-operator limit. An equivalent way of writing that is: int m = 0x7FFF; … Read more