#include <cmath>
 
bool prime(unsigned n)
{
	switch (n)
	{
		case 0:
		case 1:
			return false;
		case 2:
		case 3:
			return true;
		default:
			break;
	}
 
	double dSq = sqrt((double)n);
	unsigned sqrt = (int)dSq;
 
	unsigned prime;
	// check 2 to sqrt for divisibility
	__asm
	{
		mov esi, n    
		mov edi, sqrt
 
		mov ebx, 1  
		mov ecx, 1   
		_loop:
		inc ecx       
		cmp ecx, edi   
		ja _end       
		mov eax, esi
		xor edx, edx
		div ecx
		cmp edx, 0 
		jne _loop
		mov ebx, 0
 
		_end:
		mov prime, ebx
	}
	return (prime == 1);
}

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