Are 64 bit assignments in Java atomic on a 32 bit machine?

Question

If I have code like this -

long x;
x  = 0xFFFFFFFFL;

If i run this code on a 32 bit machine is it guaranteed to be atomic or is it po

Answer 1

Section 8.4 of the Java Virtual Machine specification states that a double or long that is not declared volatile is treated as two 32-bit variables for load, store, read and write operations.

Furthermore, the manner of encoding and the order of the two 32-bit operations is not defined.

The spec does encourage implementations to make the operation atomic but they do not require it.