(a) Whenever any person over eighteen (18) years of age is convicted of any felony or other crime punishable by imprisonment in the penitentiary, with the punishment for the offense within minimum and maximum terms provided for by law, the jury, in addition to finding the defendant guilty, shall fix the minimum and maximum term of the convicted defendant; provided, that the minimum sentence so fixed shall not be increased to exceed more than twice the minimum sentence as provided by law or the minimum sentence provided by law plus one half (½) the difference between the minimum and maximum sentence as provided by law, whichever is less. Its form of verdict shall be: “We find the defendant guilty as charged in the indictment” or “We find the defendant guilty of ____ (whatever may be the offense charged), and fix punishment at imprisonment in the penitentiary for not less than ____ years nor more than ____ years,” and the court imposing judgment upon the verdict shall not fix a definite term of imprisonment, but shall sentence the person to the penitentiary for a period of not less than nor more than the term fixed by the jury, making allowance for good time as now provided by law.

(b) This section shall have no application in the case of persons convicted of second degree murder, rape of a female over the age of twelve (12) years, carnal knowledge and abuse of a female under the age of twelve (12) years, assault and battery upon a female under the age of twelve (12) years with the intent to unlawfully carnally know her, robbery by the use of a deadly weapon, kidnapping for ransom, or any Class X felony. Persons convicted of the offenses of this subsection (b) shall be given a determinate, and not an indeterminate sentence.