1. Except as otherwise provided in subsection 2, whenever a sentence of imprisonment in the county jail or state prison is imposed, the court may order that credit be allowed against the duration of the sentence, including any minimum term or minimum aggregate term, as applicable, thereof prescribed by law, for the amount of time which the defendant has actually spent in confinement before conviction, unless the defendant’s confinement was pursuant to a judgment of conviction for another offense. Credit allowed pursuant to this subsection does not alter the date from which the term of imprisonment is computed.
2. A defendant who is convicted of a subsequent offense which was committed while the defendant was:
(a) In custody on a prior charge is not eligible for any credit on the sentence for the subsequent offense for time the defendant has spent in confinement on the prior charge, unless the charge was dismissed or the defendant was acquitted.
(b) Imprisoned in a county jail or state prison or on probation or parole from a Nevada conviction is not eligible for any credit on the sentence for the subsequent offense for the time the defendant has spent in confinement which is within the period of the prior sentence, regardless of whether any probation or parole has been formally revoked.