OpenCores
URL https://opencores.org/ocsvn/openrisc/openrisc/trunk

Subversion Repositories openrisc

[/] [openrisc/] [trunk/] [gnu-dev/] [or1k-gcc/] [boehm-gc/] [include/] [private/] [gc_hdrs.h] - Blame information for rev 721

Details | Compare with Previous | View Log

Line No. Rev Author Line
1 721 jeremybenn
/*
2
 * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
3
 * Copyright (c) 1991-1994 by Xerox Corporation.  All rights reserved.
4
 *
5
 * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
6
 * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
7
 *
8
 * Permission is hereby granted to use or copy this program
9
 * for any purpose,  provided the above notices are retained on all copies.
10
 * Permission to modify the code and to distribute modified code is granted,
11
 * provided the above notices are retained, and a notice that the code was
12
 * modified is included with the above copyright notice.
13
 */
14
/* Boehm, July 11, 1995 11:54 am PDT */
15
# ifndef GC_HEADERS_H
16
# define GC_HEADERS_H
17
typedef struct hblkhdr hdr;
18
 
19
# if CPP_WORDSZ != 32 && CPP_WORDSZ < 36
20
        --> Get a real machine.
21
# endif
22
 
23
/*
24
 * The 2 level tree data structure that is used to find block headers.
25
 * If there are more than 32 bits in a pointer, the top level is a hash
26
 * table.
27
 *
28
 * This defines HDR, GET_HDR, and SET_HDR, the main macros used to
29
 * retrieve and set object headers.
30
 *
31
 * Since 5.0 alpha 5, we can also take advantage of a header lookup
32
 * cache.  This is a locally declared direct mapped cache, used inside
33
 * the marker.  The HC_GET_HDR macro uses and maintains this
34
 * cache.  Assuming we get reasonable hit rates, this shaves a few
35
 * memory references from each pointer validation.
36
 */
37
 
38
# if CPP_WORDSZ > 32
39
#   define HASH_TL
40
# endif
41
 
42
/* Define appropriate out-degrees for each of the two tree levels       */
43
# ifdef SMALL_CONFIG
44
#   define LOG_BOTTOM_SZ 11
45
        /* Keep top index size reasonable with smaller blocks. */
46
# else
47
#   define LOG_BOTTOM_SZ 10
48
# endif
49
# ifndef HASH_TL
50
#   define LOG_TOP_SZ (WORDSZ - LOG_BOTTOM_SZ - LOG_HBLKSIZE)
51
# else
52
#   define LOG_TOP_SZ 11
53
# endif
54
# define TOP_SZ (1 << LOG_TOP_SZ)
55
# define BOTTOM_SZ (1 << LOG_BOTTOM_SZ)
56
 
57
#ifndef SMALL_CONFIG
58
# define USE_HDR_CACHE
59
#endif
60
 
61
/* #define COUNT_HDR_CACHE_HITS  */
62
 
63
extern hdr * GC_invalid_header; /* header for an imaginary block        */
64
                                /* containing no objects.               */
65
 
66
 
67
/* Check whether p and corresponding hhdr point to long or invalid      */
68
/* object.  If so, advance hhdr to                                      */
69
/* beginning of block, or set hhdr to GC_invalid_header.                */
70
#define ADVANCE(p, hhdr, source) \
71
            { \
72
              hdr * new_hdr = GC_invalid_header; \
73
              p = GC_find_start(p, hhdr, &new_hdr); \
74
              hhdr = new_hdr; \
75
            }
76
 
77
#ifdef USE_HDR_CACHE
78
 
79
# ifdef COUNT_HDR_CACHE_HITS
80
    extern word GC_hdr_cache_hits;
81
    extern word GC_hdr_cache_misses;
82
#   define HC_HIT() ++GC_hdr_cache_hits
83
#   define HC_MISS() ++GC_hdr_cache_misses
84
# else
85
#   define HC_HIT()
86
#   define HC_MISS()
87
# endif
88
 
89
  typedef struct hce {
90
    word block_addr;    /* right shifted by LOG_HBLKSIZE */
91
    hdr * hce_hdr;
92
  } hdr_cache_entry;
93
 
94
# define HDR_CACHE_SIZE 8  /* power of 2 */
95
 
96
# define DECLARE_HDR_CACHE \
97
        hdr_cache_entry hdr_cache[HDR_CACHE_SIZE]
98
 
99
# define INIT_HDR_CACHE BZERO(hdr_cache, sizeof(hdr_cache));
100
 
101
# define HCE(h) hdr_cache + (((word)(h) >> LOG_HBLKSIZE) & (HDR_CACHE_SIZE-1))
102
 
103
# define HCE_VALID_FOR(hce,h) ((hce) -> block_addr == \
104
                                ((word)(h) >> LOG_HBLKSIZE))
105
 
106
# define HCE_HDR(h) ((hce) -> hce_hdr)
107
 
108
 
109
/* Analogous to GET_HDR, except that in the case of large objects, it   */
110
/* Returns the header for the object beginning, and updates p.          */
111
/* Returns GC_invalid_header instead of 0.  All of this saves a branch  */
112
/* in the fast path.                                                    */
113
# define HC_GET_HDR(p, hhdr, source) \
114
        { \
115
          hdr_cache_entry * hce = HCE(p); \
116
          if (HCE_VALID_FOR(hce, p)) { \
117
            HC_HIT(); \
118
            hhdr = hce -> hce_hdr; \
119
          } else { \
120
            HC_MISS(); \
121
            GET_HDR(p, hhdr); \
122
            if (IS_FORWARDING_ADDR_OR_NIL(hhdr)) { \
123
              ADVANCE(p, hhdr, source); \
124
            } else { \
125
              hce -> block_addr = (word)(p) >> LOG_HBLKSIZE; \
126
              hce -> hce_hdr = hhdr; \
127
            } \
128
          } \
129
        }
130
 
131
#else /* !USE_HDR_CACHE */
132
 
133
# define DECLARE_HDR_CACHE
134
 
135
# define INIT_HDR_CACHE
136
 
137
# define HC_GET_HDR(p, hhdr, source) \
138
        { \
139
          GET_HDR(p, hhdr); \
140
          if (IS_FORWARDING_ADDR_OR_NIL(hhdr)) { \
141
            ADVANCE(p, hhdr, source); \
142
          } \
143
        }
144
#endif
145
 
146
typedef struct bi {
147
    hdr * index[BOTTOM_SZ];
148
        /*
149
         * The bottom level index contains one of three kinds of values:
150
         * 0 means we're not responsible for this block,
151
         *   or this is a block other than the first one in a free block.
152
         * 1 < (long)X <= MAX_JUMP means the block starts at least
153
         *        X * HBLKSIZE bytes before the current address.
154
         * A valid pointer points to a hdr structure. (The above can't be
155
         * valid pointers due to the GET_MEM return convention.)
156
         */
157
    struct bi * asc_link;       /* All indices are linked in    */
158
                                /* ascending order...           */
159
    struct bi * desc_link;      /* ... and in descending order. */
160
    word key;                   /* high order address bits.     */
161
# ifdef HASH_TL
162
    struct bi * hash_link;      /* Hash chain link.             */
163
# endif
164
} bottom_index;
165
 
166
/* extern bottom_index GC_all_nils; - really part of GC_arrays */
167
 
168
/* extern bottom_index * GC_top_index []; - really part of GC_arrays */
169
                                /* Each entry points to a bottom_index. */
170
                                /* On a 32 bit machine, it points to    */
171
                                /* the index for a set of high order    */
172
                                /* bits equal to the index.  For longer */
173
                                /* addresses, we hash the high order    */
174
                                /* bits to compute the index in         */
175
                                /* GC_top_index, and each entry points  */
176
                                /* to a hash chain.                     */
177
                                /* The last entry in each chain is      */
178
                                /* GC_all_nils.                         */
179
 
180
 
181
# define MAX_JUMP (HBLKSIZE - 1)
182
 
183
# define HDR_FROM_BI(bi, p) \
184
                ((bi)->index[((word)(p) >> LOG_HBLKSIZE) & (BOTTOM_SZ - 1)])
185
# ifndef HASH_TL
186
#   define BI(p) (GC_top_index \
187
                [(word)(p) >> (LOG_BOTTOM_SZ + LOG_HBLKSIZE)])
188
#   define HDR_INNER(p) HDR_FROM_BI(BI(p),p)
189
#   ifdef SMALL_CONFIG
190
#       define HDR(p) GC_find_header((ptr_t)(p))
191
#   else
192
#       define HDR(p) HDR_INNER(p)
193
#   endif
194
#   define GET_BI(p, bottom_indx) (bottom_indx) = BI(p)
195
#   define GET_HDR(p, hhdr) (hhdr) = HDR(p)
196
#   define SET_HDR(p, hhdr) HDR_INNER(p) = (hhdr)
197
#   define GET_HDR_ADDR(p, ha) (ha) = &(HDR_INNER(p))
198
# else /* hash */
199
/*  Hash function for tree top level */
200
#   define TL_HASH(hi) ((hi) & (TOP_SZ - 1))
201
/*  Set bottom_indx to point to the bottom index for address p */
202
#   define GET_BI(p, bottom_indx) \
203
        { \
204
            register word hi = \
205
                (word)(p) >> (LOG_BOTTOM_SZ + LOG_HBLKSIZE); \
206
            register bottom_index * _bi = GC_top_index[TL_HASH(hi)]; \
207
            \
208
            while (_bi -> key != hi && _bi != GC_all_nils) \
209
                _bi = _bi -> hash_link; \
210
            (bottom_indx) = _bi; \
211
        }
212
#   define GET_HDR_ADDR(p, ha) \
213
        { \
214
            register bottom_index * bi; \
215
            \
216
            GET_BI(p, bi);      \
217
            (ha) = &(HDR_FROM_BI(bi, p)); \
218
        }
219
#   define GET_HDR(p, hhdr) { register hdr ** _ha; GET_HDR_ADDR(p, _ha); \
220
                              (hhdr) = *_ha; }
221
#   define SET_HDR(p, hhdr) { register hdr ** _ha; GET_HDR_ADDR(p, _ha); \
222
                              *_ha = (hhdr); }
223
#   define HDR(p) GC_find_header((ptr_t)(p))
224
# endif
225
 
226
/* Is the result a forwarding address to someplace closer to the        */
227
/* beginning of the block or NIL?                                       */
228
# define IS_FORWARDING_ADDR_OR_NIL(hhdr) ((unsigned long) (hhdr) <= MAX_JUMP)
229
 
230
/* Get an HBLKSIZE aligned address closer to the beginning of the block */
231
/* h.  Assumes hhdr == HDR(h) and IS_FORWARDING_ADDR(hhdr).             */
232
# define FORWARDED_ADDR(h, hhdr) ((struct hblk *)(h) - (unsigned long)(hhdr))
233
# endif /*  GC_HEADERS_H */

powered by: WebSVN 2.1.0

© copyright 1999-2024 OpenCores.org, equivalent to Oliscience, all rights reserved. OpenCores®, registered trademark.