Answer by GJ. for atomicity in 32/64 bit

Not by default! But some SSE instructions under x86 support 64bit and 128bit atomic load/store, of course you must first ensure memory aligment. Look examples:

procedure Move64(var Source, Destination);//Move 8 bytes atomicly from Source 8-byte aligned to Destination!asm  movq  xmm0, qword [Source]  movq  qword [Destination], xmm0end;procedure Move64(newData: pointer; newReference: cardinal; var Destination); overload; //Move 8 bytes atomically into 8-byte Destination!asm  movd  xmm0, eax  movd  xmm1, edx  punpckldq xmm0, xmm1  movq  qword [Destination], xmm0end; procedure Move128(var Source, Destination);//Move 16 bytes atomicly from Source to 16-byte aligned to Destination!asm  movdqa  xmm0, dqword [Source]  movdqa  dqword [Destination], xmm0end;