J'ai trouvé ça sinon (dans l'
ultimate 83plus.inc de brandonw) :
lastEntryPTR	equ 8DA7h ;pointer to the next available byte in the entry stack
lastEntryStk	equ 8DA9h ;the start of entry stack (note last entry is not in the stack, it is in the program '#'.)  This is a stack of strings.  first 2 bytes are length, followed by string. 2nd from last entry is first in this stack.
numLastEntries	equ 8E29h ;number of entries you can back-track through minus one
currLastEntry	equ 8E2Ah ;counter used by OS to keep track of which entry was just displayed by pressing 2nd+enter
Je ne sais pas si c'est la même chose sur 83, mais sans doute que 
_getlastentry et 
_getlastentryptr permettent de récupérer les adresses de la pile des entrées (et du "prochain emplacement vide" de cette pile)...