presto-hive/src/main/java/io/prestosql/plugin/hive/coercions/DecimalCoercers.java/DecimalCoercers/ShortDecimalToShortDecimalCoercer
class DecimalCoercers:        public ShortDecimalToShortDecimalCoercer(DecimalType fromType, DecimalType toType)
        {
            super(fromType, toType);
            rescale = longTenToNth(Math.abs(toType.getScale() - fromType.getScale()));
        }