Declension table of ?pūrvasasya

Neuter	Singular	Dual	Plural
Nominative	pūrvasasyam	pūrvasasye	pūrvasasyāni
Vocative	pūrvasasya	pūrvasasye	pūrvasasyāni
Accusative	pūrvasasyam	pūrvasasye	pūrvasasyāni
Instrumental	pūrvasasyena	pūrvasasyābhyām	pūrvasasyaiḥ
Dative	pūrvasasyāya	pūrvasasyābhyām	pūrvasasyebhyaḥ
Ablative	pūrvasasyāt	pūrvasasyābhyām	pūrvasasyebhyaḥ
Genitive	pūrvasasyasya	pūrvasasyayoḥ	pūrvasasyānām
Locative	pūrvasasye	pūrvasasyayoḥ	pūrvasasyeṣu

Compound pūrvasasya -

Adverb -pūrvasasyam -pūrvasasyāt