Garbage Collection for Prolog Based on WAM (Revised version)

Appleby, Karen and Carlsson, Mats and Haridi, Seif and Sahlin, Dan (1986) Garbage Collection for Prolog Based on WAM (Revised version). [SICS Report]



Warren Abstract Machine (WAM) has become a generally accepted standard Prolog implementation technique. Garbage collection is an important aspect in the implementation of any Prolog system. We first present a synopsis of the WAM and then show marking and compaction algorithms that take advantage of WAM's unique use of the data areas. Marking and compaction are performed on both the heap and the trail. The marking and compaction algorithms use pointer reversal techniques, which obviate the need for extra stack space. However, two bits for every pointer on the heap are reserved for the garbage collection algorithm. The algorithm can work on segments of the heap, which may lead to a significant reduction of the total garbage collection time. The time of the algorithms are linear in the size of the areas.

Item Type:SICS Report
Additional Information:Original report number 86009B. Revised report. (Also published in Communications of the ACM, June 1989, pp. 719-740.)
ID Code:2009
Deposited By:Vicki Carleson
Deposited On:15 Sep 2009
Last Modified:18 Nov 2009 15:59

Repository Staff Only: item control page