2 * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
3 * Copyright (c) 1991-1994 by Xerox Corporation. All rights reserved.
5 * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
6 * OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
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.
14 * This file contains the functions:
15 * ptr_t GC_build_flXXX(h, old_fl)
18 /* Boehm, May 19, 1994 2:09 pm PDT */
26 * Build a free list for size 1 objects inside hblk h. Set the last link to
27 * be ofl. Return a pointer tpo the first free list entry.
29 ptr_t
GC_build_fl1(h
, ofl
)
33 register word
* p
= (word
*)h
;
34 register word
* lim
= (word
*)(h
+ 1);
41 for (; p
< lim
; p
+= 4) {
50 /* The same for size 2 cleared objects */
51 ptr_t
GC_build_fl_clear2(h
, ofl
)
55 register word
* p
= (word
*)h
;
56 register word
* lim
= (word
*)(h
+ 1);
63 for (; p
< lim
; p
+= 4) {
72 /* The same for size 3 cleared objects */
73 ptr_t
GC_build_fl_clear3(h
, ofl
)
77 register word
* p
= (word
*)h
;
78 register word
* lim
= (word
*)(h
+ 1) - 2;
84 for (; p
< lim
; p
+= 3) {
92 /* The same for size 4 cleared objects */
93 ptr_t
GC_build_fl_clear4(h
, ofl
)
97 register word
* p
= (word
*)h
;
98 register word
* lim
= (word
*)(h
+ 1);
105 for (; p
< lim
; p
+= 4) {
106 PREFETCH_FOR_WRITE(p
+64);
111 return((ptr_t
)(p
-4));
114 /* The same for size 2 uncleared objects */
115 ptr_t
GC_build_fl2(h
, ofl
)
119 register word
* p
= (word
*)h
;
120 register word
* lim
= (word
*)(h
+ 1);
125 for (; p
< lim
; p
+= 4) {
129 return((ptr_t
)(p
-2));
132 /* The same for size 4 uncleared objects */
133 ptr_t
GC_build_fl4(h
, ofl
)
137 register word
* p
= (word
*)h
;
138 register word
* lim
= (word
*)(h
+ 1);
143 for (; p
< lim
; p
+= 8) {
144 PREFETCH_FOR_WRITE(p
+64);
148 return((ptr_t
)(p
-4));
151 #endif /* !SMALL_CONFIG */
154 * Allocate a new heapblock for small objects of size n.
155 * Add all of the heapblock's objects to the free list for objects
157 * Set all mark bits if objects are uncollectable.
158 * Will fail to do anything if we are out of memory.
160 void GC_new_hblk(sz
, kind
)
166 word
*last_object
; /* points to last object in new hblk */
167 register struct hblk
*h
; /* the new heap block */
168 register GC_bool clear
= GC_obj_kinds
[kind
].ok_init
;
171 if ((sizeof (struct hblk
)) > HBLKSIZE
) {
172 ABORT("HBLK SZ inconsistency");
176 /* Allocate a new heap block */
177 h
= GC_allochblk(sz
, kind
, 0);
180 /* Mark all objects if appropriate. */
181 if (IS_UNCOLLECTABLE(kind
)) GC_set_hdr_marks(HDR(h
));
183 PREFETCH_FOR_WRITE((char *)h
);
184 PREFETCH_FOR_WRITE((char *)h
+ 128);
185 PREFETCH_FOR_WRITE((char *)h
+ 256);
186 PREFETCH_FOR_WRITE((char *)h
+ 378);
187 /* Handle small objects sizes more efficiently. For larger objects */
188 /* the difference is less significant. */
189 # ifndef SMALL_CONFIG
191 case 1: GC_obj_kinds
[kind
].ok_freelist
[1] =
192 GC_build_fl1(h
, GC_obj_kinds
[kind
].ok_freelist
[1]);
195 GC_obj_kinds
[kind
].ok_freelist
[2] =
196 GC_build_fl_clear2(h
, GC_obj_kinds
[kind
].ok_freelist
[2]);
198 GC_obj_kinds
[kind
].ok_freelist
[2] =
199 GC_build_fl2(h
, GC_obj_kinds
[kind
].ok_freelist
[2]);
203 GC_obj_kinds
[kind
].ok_freelist
[3] =
204 GC_build_fl_clear3(h
, GC_obj_kinds
[kind
].ok_freelist
[3]);
207 /* It's messy to do better than the default here. */
211 GC_obj_kinds
[kind
].ok_freelist
[4] =
212 GC_build_fl_clear4(h
, GC_obj_kinds
[kind
].ok_freelist
[4]);
214 GC_obj_kinds
[kind
].ok_freelist
[4] =
215 GC_build_fl4(h
, GC_obj_kinds
[kind
].ok_freelist
[4]);
221 # endif /* !SMALL_CONFIG */
223 /* Clear the page if necessary. */
224 if (clear
) BZERO(h
, HBLKSIZE
);
226 /* Add objects to free list */
227 p
= &(h
-> hb_body
[sz
]); /* second object in *h */
228 prev
= &(h
-> hb_body
[0]); /* One object behind p */
229 last_object
= (word
*)((char *)h
+ HBLKSIZE
);
231 /* Last place for last object to start */
233 /* make a list of all objects in *h with head as last object */
234 while (p
<= last_object
) {
235 /* current object's link points to last object */
236 obj_link(p
) = (ptr_t
)prev
;
240 p
-= sz
; /* p now points to last object */
243 * put p (which is now head of list of objects in *h) as first
244 * pointer in the appropriate free list for this size.
246 obj_link(h
-> hb_body
) = GC_obj_kinds
[kind
].ok_freelist
[sz
];
247 GC_obj_kinds
[kind
].ok_freelist
[sz
] = ((ptr_t
)p
);