static unsigned long sqrt(unsigned long x)
{
register unsigned long xr; // result register
register unsigned long q2; // scan-bit register
register unsigned char f; // flag (one bit)
xr = 0; // clear result
q2 = 0x40000000L; // higest possible result bit
do
{
if((xr + q2) <= x)
{
x -= xr + q2;
f = 1; // set flag
}
else{
f = 0; // clear flag
}
xr >>= 1;
if(f){
xr += q2; // test flag
}
} while(q2 >>= 2); // shift twice
if(xr < x){
return xr +1; // add for rounding
}
else{
return xr;
}
}
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