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900c9557ab
The Lisp implementation distinguishes between 0 and NIL as the result of
the gcscan1/gcscan2 opcodes, however the C implementation did not, since
NIL and 0 are indistinguishable.
95 lines
4.2 KiB
C
95 lines
4.2 KiB
C
/* $Id: gcscan.c,v 1.3 1999/05/31 23:35:33 sybalsky Exp $ (C) Copyright Venue, All Rights Reserved
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*/
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/************************************************************************/
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/* */
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/* (C) Copyright 1989-95 Venue. All Rights Reserved. */
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/* Manufactured in the United States of America. */
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/* */
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/************************************************************************/
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#include "version.h"
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/*************************************************************************/
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/* */
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/* File Name : gcscan.c */
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/* */
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/*************************************************************************/
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/* */
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/* Creation Date : July-7-1987 */
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/* Written by Tomoru Teruuchi */
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/* */
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/*************************************************************************/
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/* */
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/* Functions : */
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/* gcscan1(probe) */
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/* gcscan2(probe) */
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/* */
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/*************************************************************************/
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/* Description : */
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/* */
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/* The functions "gcscan1" and "gcscan2" are the translated functions */
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/* from the Lisp Functions "\GCSCAN1" & "\GCSCAN2". */
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/* These functions' role is to scan the HTmain Table and return the */
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/* existing entry(by "gcscan1") & the entry whose STKBIT field is ON */
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/* (by "gcscan2").These functions are the UFN functions that are called */
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/* by OPCODES "GCSCAN1" & "GCSCAN2". */
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/* */
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/* gcscan1 */
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/* INPUT : probe (the starting offset in the HTmain table) */
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/* OUTPUT : the entry's offset or NIL (no more entry existing) */
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/* */
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/* gcscan2 */
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/* INPUT : probe (the starting offset in the HTmain table) */
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/* OUTPUT : the entry's offset or NIL (no more entry existing) */
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/*************************************************************************/
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/* \Tomtom */
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/*************************************************************************/
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#include "lispemul.h"
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#include "lspglob.h"
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#include "gcdata.h"
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#include "lsptypes.h"
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#include "gcscandefs.h"
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#ifdef BIGVM
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#define HTSTKBIT 0x10000 /* = 512 */
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#define HTENDS ((struct hashentry *)htlptr)
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#define GetStkCnt(entry1) ((entry1) >> 16)
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#else
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#define HTSTKBIT 0x200 /* = 512 */
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#define HTENDS ((struct hashentry *)htlptr)
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#define GetStkCnt(entry1) (entry1 >> 9)
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#endif /* BIGVM */
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int gcscan1(int probe)
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/* probe is offset */
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{
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struct htlinkptr *htlptr; /* overlay access method */
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int contents;
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while (--probe >= 0) /* End of HTmain Table ? */
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{
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/* Start addr. of scanning */
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htlptr = (struct htlinkptr *)(HTmain + probe);
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contents = ((struct htlinkptr *)GCPTR(htlptr))->contents;
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if (contents && (((struct hashentry *)GCPTR(HTENDS))->collision || (GetStkCnt(contents) == 0)))
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return (probe);
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}
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return (-1);
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}
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int gcscan2(int probe)
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/* probe is offset */
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{
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struct htlinkptr *htlptr; /* overlay access method */
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while (--probe >= 0) /* End of HTmain Table ? */
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{
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htlptr = (struct htlinkptr *)(HTmain + probe);
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/* Start addr. of scanning */
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if (((HTSTKBIT | 1) & ((struct htlinkptr *)GCPTR(htlptr))->contents) != 0)
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return (probe); /* stackref or collision ON */
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}
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return (-1);
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}
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