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/* table.c - table-handler module for linker */
/* Copyright (C) 1994 Bruce Evans */
#include "const.h"
#include "align.h"
#include "obj.h"
#include "type.h"
#include "globvar.h"
#ifdef STDC_HEADERS_MISSING
void *malloc P((unsigned size));
#else
#undef NULL
#include <stdlib.h>
#endif
#define GOLDEN 157 /* GOLDEN/HASHTABSIZE approx golden ratio */
#define HASHTABSIZE 256
PRIVATE struct symstruct *hashtab[HASHTABSIZE]; /* hash table */
PRIVATE char *tableptr; /* next free spot in catchall table */
PRIVATE char *tableend; /* ptr to spot after last in table */
FORWARD struct symstruct **gethashptr P((char *name));
/* initialise symbol table */
PUBLIC void syminit()
{
unsigned i;
for (i = sizeof(int) <= 2 ? 0xE000 : (unsigned) 0x38000;
i != 0; i -= 512)
if ((tableptr = malloc(i)) != NULL)
break;
if (tableptr == NULL)
outofmemory();
tableend = tableptr + i;
for (i = 0; i < HASHTABSIZE; i++)
hashtab[i] = NULL;
}
/* add named symbol to end of table - initialise only name and next fields */
/* caller must not duplicate names of externals for findsym() to work */
PUBLIC struct symstruct *addsym(name)
char *name;
{
struct symstruct **hashptr;
struct symstruct *oldsymptr;
struct symstruct *symptr;
hashptr = gethashptr(name);
symptr = *hashptr;
while (symptr != NULL)
{
oldsymptr = symptr;
symptr = symptr->next;
}
align(tableptr);
symptr = (struct symstruct *) tableptr;
if ((tableptr = symptr->name + (strlen(name) + 1)) > tableend)
outofmemory();
symptr->modptr = NULL;
symptr->next = NULL;
if (name != symptr->name)
strcpy(symptr->name, name); /* should't happen */
if (*hashptr == NULL)
*hashptr = symptr;
else
oldsymptr->next = symptr;
return symptr;
}
/* lookup named symbol */
PUBLIC struct symstruct *findsym(name)
char *name;
{
struct symstruct *symptr;
symptr = *gethashptr(name);
while (symptr != NULL && (!(symptr->flags & (E_MASK | I_MASK)) ||
strcmp(symptr->name, name) != 0))
symptr = symptr->next;
return symptr;
}
/* convert name to a hash table ptr */
PRIVATE struct symstruct **gethashptr(name)
register char *name;
{
register unsigned hashval;
hashval = 0;
while (*name)
hashval = hashval * 2 + *name++;
return hashtab + ((hashval * GOLDEN) & (HASHTABSIZE - 1));
/*
#asm
GOLDEN EQU 157
HASHTABSIZE EQU 256
CLRB can build value here since HASHTABSIZE <= 256
LDA ,X
BEQ HASHVAL.EXIT
HASHVAL.LOOP
ADDB ,X+
LSLB
LDA ,X
BNE HASHVAL.LOOP
RORB
LDA #GOLDEN
MUL
HASHVAL.EXIT
HASHVAL.EXIT
LDX #_hashtab
ABX discard A - same as taking mod HASHTABSIZE
ABX
#endasm
*/
}
/* move symbol descriptor entries to top of table (no error checking) */
PUBLIC char *moveup(nbytes)
unsigned nbytes;
{
register char *source;
register char *target;
source = tableptr;
target = tableend;
while (nbytes--)
*--target = *--source;
tableptr = source;
return tableend = target;
}
/* our version of malloc */
PUBLIC char *ourmalloc(nbytes)
unsigned nbytes;
{
char *allocptr;
align(tableptr);
allocptr = tableptr;
if ((tableptr += nbytes) > tableend)
outofmemory();
return allocptr;
}
/* our version of free (release from bottom of table) */
PUBLIC void ourfree(cptr)
char *cptr;
{
tableptr = cptr;
}
/* read string from file into table at offset suitable for next symbol */
PUBLIC char *readstring()
{
int c;
char *s;
char *start;
align(tableptr);
start = s = ((struct symstruct *) tableptr)->name;
while (TRUE)
{
if (s >= tableend)
outofmemory();
if ((c = readchar()) < 0)
prematureeof();
if ((*s++ = c) == 0)
return start;
}
/* NOTREACHED */
}
/* release from top of table */
PUBLIC void release(cptr)
char *cptr;
{
tableend = cptr;
}
/* allocate space for string */
PUBLIC char *stralloc(s)
char *s;
{
return strcpy(ourmalloc((unsigned) strlen(s) + 1), s);
}
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