1 /* -----------------------------------------------------------------------------
2 * $Id: Block.h,v 1.9 2001/07/23 17:23:19 simonmar Exp $
4 * (c) The GHC Team, 1998-1999
6 * Block structure for the storage manager
8 * ---------------------------------------------------------------------------*/
13 /* The actual block and megablock-size constants are defined in
14 * includes/Constants.h, all constants here are derived from these.
17 /* Block related constants (4k blocks) */
19 #define BLOCK_SIZE_W (BLOCK_SIZE/sizeof(W_))
20 #define BLOCK_MASK (BLOCK_SIZE-1)
22 #define BLOCK_ROUND_UP(p) ((void *) (((W_)(p)+BLOCK_SIZE-1) & ~BLOCK_MASK))
23 #define BLOCK_ROUND_DOWN(p) ((void *) ((W_)(p) & ~BLOCK_MASK))
25 /* Megablock related constants (1M megablocks) */
27 #define MBLOCK_SIZE_W (MBLOCK_SIZE/sizeof(W_))
28 #define MBLOCK_MASK (MBLOCK_SIZE-1)
30 #define MBLOCK_ROUND_UP(p) ((void *)(((W_)(p)+MBLOCK_SIZE-1) & ~MBLOCK_MASK))
31 #define MBLOCK_ROUND_DOWN(p) ((void *)((W_)(p) & ~MBLOCK_MASK ))
34 /* -----------------------------------------------------------------------------
35 * Block descriptor. This structure *must* be the right length, so we
36 * can do pointer arithmetic on pointers to it.
39 /* The block descriptor is 64 bytes on a 64-bit machine, and 32-bytes
40 * on a 32-bit machine.
43 typedef struct _bdescr {
44 StgPtr start; /* start addr of memory */
45 StgPtr free; /* first free byte of memory */
46 struct _bdescr *link; /* used for chaining blocks together */
48 struct _bdescr *back; /* used (occasionally) for doubly-linked lists*/
51 unsigned int gen_no; /* generation */
52 struct _step *step; /* step */
53 StgWord32 blocks; /* no. of blocks (if grp head, 0 otherwise) */
54 StgWord32 flags; /* block is in to-space */
55 #if SIZEOF_VOID_P == 8
56 StgWord32 _padding[2];
58 StgWord32 _padding[0];
62 #if SIZEOF_VOID_P == 8
63 #define BDESCR_SIZE 0x40
64 #define BDESCR_MASK 0x3f
65 #define BDESCR_SHIFT 6
67 #define BDESCR_SIZE 0x20
68 #define BDESCR_MASK 0x1f
69 #define BDESCR_SHIFT 5
72 #define BF_EVACUATED 1
75 /* Finding the block descriptor for a given block -------------------------- */
77 static inline bdescr *Bdescr(StgPtr p)
80 ((((W_)p & MBLOCK_MASK & ~BLOCK_MASK) >> (BLOCK_SHIFT-BDESCR_SHIFT))
81 | ((W_)p & ~MBLOCK_MASK)
85 /* Useful Macros ------------------------------------------------------------ */
87 /* Offset of first real data block in a megablock */
89 #define FIRST_BLOCK_OFF \
90 ((W_)BLOCK_ROUND_UP(MBLOCK_SIZE / BLOCK_SIZE * BDESCR_SIZE))
92 /* First data block in a given megablock */
94 #define FIRST_BLOCK(m) ((void *)(FIRST_BLOCK_OFF + (W_)(m)))
96 /* Last data block in a given megablock */
98 #define LAST_BLOCK(m) ((void *)(MBLOCK_SIZE-BLOCK_SIZE + (W_)(m)))
100 /* First real block descriptor in a megablock */
102 #define FIRST_BDESCR(m) \
103 ((bdescr *)((FIRST_BLOCK_OFF>>(BLOCK_SHIFT-BDESCR_SHIFT)) + (W_)(m)))
105 /* Number of usable blocks in a megablock */
107 #define BLOCKS_PER_MBLOCK ((MBLOCK_SIZE - FIRST_BLOCK_OFF) / BLOCK_SIZE)
109 /* How many blocks in this megablock group */
111 #define MBLOCK_GROUP_BLOCKS(n) \
112 (BLOCKS_PER_MBLOCK + (n-1) * (MBLOCK_SIZE / BLOCK_SIZE))
114 /* Compute the required size of a megablock group */
116 #define BLOCKS_TO_MBLOCKS(n) \
117 (1 + (W_)MBLOCK_ROUND_UP((n-BLOCKS_PER_MBLOCK) * BLOCK_SIZE) / MBLOCK_SIZE)