1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
|
/* table.c - keyword tables and symbol table lookup for assembler */
#include "syshead.h"
#include "const.h"
#include "type.h"
#include "globvar.h"
#include "opcode.h"
#include "scan.h"
#define hconv(ch) ((unsigned char) (ch) - 0x41) /* better form for hashing */
#ifdef I80386
# ifdef MNSIZE
EXTERN char bytesizeops[];
# endif
#endif
EXTERN char ops[];
EXTERN char page1ops[];
EXTERN char page2ops[];
EXTERN char regs[];
#ifdef I80386
EXTERN char typesizes[];
#endif
#ifdef DEBUG_HASH
unsigned nhash;
unsigned nlookup;
unsigned nsym;
unsigned nx[30];
FORWARD void printchain P((void));
#endif
FORWARD void install P((register char *keyptr, int data));
PUBLIC void inst_keywords()
{
install(regs, REGBIT);
#ifdef I80386
install(typesizes, SIZEBIT);
#endif
install(ops, 0);
install(page1ops, PAGE1);
install(page2ops, PAGE2);
#ifdef I80386
# ifdef MNSIZE
install(bytesizeops, PAGE1 | PAGE2);
# endif
#endif
}
PRIVATE void install(keyptr, data)
register char *keyptr;
unsigned char data;
{
char lowcasebuf[20];
unsigned namelength;
char *nameptr;
char *namend;
register struct sym_s *symptr;
while (*keyptr != 0)
{
namelength = *keyptr++;
lineptr = (symname = keyptr) + namelength;
for (nameptr = lowcasebuf, namend = lowcasebuf + namelength;
nameptr < namend;)
{
if (*keyptr < 'A' || *keyptr > 'Z')
*nameptr++ = *keyptr++;
else
*nameptr++ = *keyptr++ + ('a' - 'A');
}
symptr = lookup();
symptr->type = MNREGBIT;
symptr->data = data;
symptr->value_reg_or_op.op.routine = *keyptr;
symptr->value_reg_or_op.op.opcode = keyptr[1];
lineptr = (symname = lowcasebuf) + namelength;
symptr = lookup();
symptr->type = MNREGBIT;
symptr->data = data;
symptr->value_reg_or_op.op.routine = *keyptr;
symptr->value_reg_or_op.op.opcode = keyptr[1];
keyptr += 2;
}
}
/* Lookup() searches symbol table for the string from symname to lineptr - 1.
* If string is not found and ifflag is TRUE, string is added to table, with
* type = 0
* data = inidata (RELBIT | UNDBIT, possibly with IMPBIT | SEGM)
* Returns pointer to symbol entry (NUL_PTR if not found and not installed)
* unless symbol table overflows, when routine aborts.
*/
PUBLIC struct sym_s *lookup()
{
struct sym_s **hashptr;
register char *nameptr;
register struct sym_s *symptr;
register unsigned hashval;
register unsigned length;
#ifdef DEBUG_HASH
int tries;
++nlookup;
tries = 0;
#endif
/* Hash function is a weighted xor of 1 to 4 chars in the string.
* This works seems to work better than looking at all the chars.
* It is important that the function be fast.
* The string comparision function should also be fast and it helps
* if it is optimized for mostly identical comparisions.
* The multiplication by MULTIPLIER should compile as a shift.
*/
#define MULTIPLIER (SPTSIZ / (1 << USEFUL_BITS_IN_ASCII))
#define USEFUL_BITS_IN_ASCII 6
nameptr = lineptr;
length = nameptr - symname;
if (length <= 3)
{
if (length <= 2)
hashval = hconv(nameptr[-1]) * MULTIPLIER;
else
hashval = hconv(nameptr[-2]) * MULTIPLIER,
hashval ^= hconv(nameptr[-1]);
}
else
hashval = hconv(symname[length-(length / 2)]) * MULTIPLIER,
hashval ^= hconv(nameptr[-2]) << 2,
hashval ^= hconv(nameptr[-1]);
nameptr = symname;
if ((symptr = *(hashptr = spt +
(hashval ^ (hconv(nameptr[0]) << 1)) % SPTSIZ))
!= NUL_PTR)
{
do
{
#ifdef DEBUG_HASH
if (tries != 0)
--nx[tries];
++tries;
if (tries < sizeof nx / sizeof nx[0])
++nx[tries];
if (tries >= 5)
printchain(hashptr - spt);
#endif
if ((unsigned char) length != symptr->length)
continue;
if (memcmp(symptr->name, nameptr, length) == 0)
return symptr;
}
while ((symptr = symptr->next) != NUL_PTR);
/* Calculate last non-NUL_PTR hash ptr.
* This is faster than keeping hashptr up to date in previous loop
* since most lookups are successful and hash ptr is not needed.
*/
do
{
symptr = *hashptr;
hashptr = &symptr->next;
}
while (symptr->next != NUL_PTR);
}
if (!ifflag)
return NUL_PTR;
#ifdef DEBUG_HASH
++nsym;
if (hashptr >= spt && hashptr < spt + SPTSIZ)
++nhash;
#endif
*hashptr = symptr = asalloc(sizeof(struct sym_s) + length);
symptr->type = 0;
symptr->data = inidata;
symptr->length = length;
symptr->value_reg_or_op.value = (offset_t) (symptr->next = NUL_PTR);
memcpy(symptr->name, nameptr, length);
symptr->name[length] = 0;
return symptr;
}
#ifdef DEBUG_HASH
static void printchain(hashval)
unsigned hashval;
{
register struct sym_s *symptr;
printf("%04x ", hashval);
for (symptr = spt[hashval]; symptr != NUL_PTR; symptr = symptr->next)
printf("%s ", symptr->name);
printf("\n");
}
#endif
PUBLIC void statistics()
{
#ifdef DEBUG_HASH
int i;
int weight;
for (i = 0; i < SPTSIZ; ++i)
printchain(i);
printf("nhash = %d, nsym = %d, nlookup = %d nx =\n", nhash, nsym, nlookup);
weight = 0;
for (i = 0; i < 30; ++i)
{
printf("%5d", nx[i]);
weight += nx[i] * i;
}
printf("\n");
printf("weight = %d%d\n", weight);
#endif
}
|
