On perl-5.30.0 whose nvsize is 8 (and whose nvtype is 'double':
C:\>perl -V:nvsize
nvsize='8';

C:\>perl -le "print int(1000 * 0.001);"
1

On perl-5.30.0 whose nvsize is 12 or 16 (and whose nvtype is 'long double'):
C:\>perl -V:nvsize
nvsize='16';

C:\>perl -le "print int(1000 * 0.001);"
0