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/* -----------------------------------------------------------------------------
* $Id: Block.h,v 1.7 2000/04/05 14:26:31 panne Exp $
*
* (c) The GHC Team, 1998-1999
*
* Block structure for the storage manager
*
* ---------------------------------------------------------------------------*/
#ifndef BLOCK_H
#define BLOCK_H
/* The actual block and megablock-size constants are defined in
* includes/Constants.h, all constants here are derived from these.
*/
/* Block related constants (4k blocks) */
#define BLOCK_SIZE_W (BLOCK_SIZE/sizeof(W_))
#define BLOCK_MASK (BLOCK_SIZE-1)
#define BLOCK_ROUND_UP(p) ((void *) (((W_)(p)+BLOCK_SIZE-1) & ~BLOCK_MASK))
#define BLOCK_ROUND_DOWN(p) ((void *) ((W_)(p) & ~BLOCK_MASK))
/* Megablock related constants (1M megablocks) */
#define MBLOCK_SIZE_W (MBLOCK_SIZE/sizeof(W_))
#define MBLOCK_MASK (MBLOCK_SIZE-1)
#define MBLOCK_ROUND_UP(p) ((void *)(((W_)(p)+MBLOCK_SIZE-1) & ~MBLOCK_MASK))
#define MBLOCK_ROUND_DOWN(p) ((void *)((W_)(p) & ~MBLOCK_MASK ))
/* -----------------------------------------------------------------------------
* Block descriptor. This structure *must* be the right length, so we
* can do pointer arithmetic on pointers to it.
*/
/* The block descriptor is 64 bytes on a 64-bit machine, and 32-bytes
* on a 32-bit machine.
*/
typedef struct _bdescr {
StgPtr start; /* start addr of memory */
StgPtr free; /* first free byte of memory */
struct _bdescr *link; /* used for chaining blocks together */
struct _bdescr *back; /* used (occasionally) for doubly-linked lists*/
struct _generation *gen; /* generation */
struct _step *step; /* step */
StgWord32 blocks; /* no. of blocks (if grp head, 0 otherwise) */
StgWord32 evacuated; /* block is in to-space */
#if SIZEOF_VOID_P == 8
StgWord32 _padding[2];
#else
StgWord32 _padding[0];
#endif
} bdescr;
#if SIZEOF_VOID_P == 8
#define BDESCR_SIZE 0x40
#define BDESCR_MASK 0x3f
#define BDESCR_SHIFT 6
#else
#define BDESCR_SIZE 0x20
#define BDESCR_MASK 0x1f
#define BDESCR_SHIFT 5
#endif
/* Finding the block descriptor for a given block -------------------------- */
static inline bdescr *Bdescr(StgPtr p)
{
return (bdescr *)
((((W_)p & MBLOCK_MASK & ~BLOCK_MASK) >> (BLOCK_SHIFT-BDESCR_SHIFT))
| ((W_)p & ~MBLOCK_MASK)
);
}
/* Useful Macros ------------------------------------------------------------ */
/* Offset of first real data block in a megablock */
#define FIRST_BLOCK_OFF \
((W_)BLOCK_ROUND_UP(MBLOCK_SIZE / BLOCK_SIZE * BDESCR_SIZE))
/* First data block in a given megablock */
#define FIRST_BLOCK(m) ((void *)(FIRST_BLOCK_OFF + (W_)(m)))
/* Last data block in a given megablock */
#define LAST_BLOCK(m) ((void *)(MBLOCK_SIZE-BLOCK_SIZE + (W_)(m)))
/* First real block descriptor in a megablock */
#define FIRST_BDESCR(m) \
((bdescr *)((FIRST_BLOCK_OFF>>(BLOCK_SHIFT-BDESCR_SHIFT)) + (W_)(m)))
/* Number of usable blocks in a megablock */
#define BLOCKS_PER_MBLOCK ((MBLOCK_SIZE - FIRST_BLOCK_OFF) / BLOCK_SIZE)
/* How many blocks in this megablock group */
#define MBLOCK_GROUP_BLOCKS(n) \
(BLOCKS_PER_MBLOCK + (n-1) * (MBLOCK_SIZE / BLOCK_SIZE))
/* Compute the required size of a megablock group */
#define BLOCKS_TO_MBLOCKS(n) \
(1 + (W_)MBLOCK_ROUND_UP((n-BLOCKS_PER_MBLOCK) * BLOCK_SIZE) / MBLOCK_SIZE)
#endif /* BLOCK_H */
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