Annotation of OpenXM_contrib2/asir2000/gc/include/private/gc_hdrs.h, Revision 1.1
1.1 ! noro 1: /*
! 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:
! 29: # if CPP_WORDSZ > 32
! 30: # define HASH_TL
! 31: # endif
! 32:
! 33: /* Define appropriate out-degrees for each of the two tree levels */
! 34: # ifdef SMALL_CONFIG
! 35: # define LOG_BOTTOM_SZ 11
! 36: /* Keep top index size reasonable with smaller blocks. */
! 37: # else
! 38: # define LOG_BOTTOM_SZ 10
! 39: # endif
! 40: # ifndef HASH_TL
! 41: # define LOG_TOP_SZ (WORDSZ - LOG_BOTTOM_SZ - LOG_HBLKSIZE)
! 42: # else
! 43: # define LOG_TOP_SZ 11
! 44: # endif
! 45: # define TOP_SZ (1 << LOG_TOP_SZ)
! 46: # define BOTTOM_SZ (1 << LOG_BOTTOM_SZ)
! 47:
! 48: typedef struct bi {
! 49: hdr * index[BOTTOM_SZ];
! 50: /*
! 51: * The bottom level index contains one of three kinds of values:
! 52: * 0 means we're not responsible for this block,
! 53: * or this is a block other than the first one in a free block.
! 54: * 1 < (long)X <= MAX_JUMP means the block starts at least
! 55: * X * HBLKSIZE bytes before the current address.
! 56: * A valid pointer points to a hdr structure. (The above can't be
! 57: * valid pointers due to the GET_MEM return convention.)
! 58: */
! 59: struct bi * asc_link; /* All indices are linked in */
! 60: /* ascending order... */
! 61: struct bi * desc_link; /* ... and in descending order. */
! 62: word key; /* high order address bits. */
! 63: # ifdef HASH_TL
! 64: struct bi * hash_link; /* Hash chain link. */
! 65: # endif
! 66: } bottom_index;
! 67:
! 68: /* extern bottom_index GC_all_nils; - really part of GC_arrays */
! 69:
! 70: /* extern bottom_index * GC_top_index []; - really part of GC_arrays */
! 71: /* Each entry points to a bottom_index. */
! 72: /* On a 32 bit machine, it points to */
! 73: /* the index for a set of high order */
! 74: /* bits equal to the index. For longer */
! 75: /* addresses, we hash the high order */
! 76: /* bits to compute the index in */
! 77: /* GC_top_index, and each entry points */
! 78: /* to a hash chain. */
! 79: /* The last entry in each chain is */
! 80: /* GC_all_nils. */
! 81:
! 82:
! 83: # define MAX_JUMP (HBLKSIZE - 1)
! 84:
! 85: # define HDR_FROM_BI(bi, p) \
! 86: ((bi)->index[((word)(p) >> LOG_HBLKSIZE) & (BOTTOM_SZ - 1)])
! 87: # ifndef HASH_TL
! 88: # define BI(p) (GC_top_index \
! 89: [(word)(p) >> (LOG_BOTTOM_SZ + LOG_HBLKSIZE)])
! 90: # define HDR_INNER(p) HDR_FROM_BI(BI(p),p)
! 91: # ifdef SMALL_CONFIG
! 92: # define HDR(p) GC_find_header((ptr_t)(p))
! 93: # else
! 94: # define HDR(p) HDR_INNER(p)
! 95: # endif
! 96: # define GET_BI(p, bottom_indx) (bottom_indx) = BI(p)
! 97: # define GET_HDR(p, hhdr) (hhdr) = HDR(p)
! 98: # define SET_HDR(p, hhdr) HDR_INNER(p) = (hhdr)
! 99: # define GET_HDR_ADDR(p, ha) (ha) = &(HDR_INNER(p))
! 100: # else /* hash */
! 101: /* Hash function for tree top level */
! 102: # define TL_HASH(hi) ((hi) & (TOP_SZ - 1))
! 103: /* Set bottom_indx to point to the bottom index for address p */
! 104: # define GET_BI(p, bottom_indx) \
! 105: { \
! 106: register word hi = \
! 107: (word)(p) >> (LOG_BOTTOM_SZ + LOG_HBLKSIZE); \
! 108: register bottom_index * _bi = GC_top_index[TL_HASH(hi)]; \
! 109: \
! 110: while (_bi -> key != hi && _bi != GC_all_nils) \
! 111: _bi = _bi -> hash_link; \
! 112: (bottom_indx) = _bi; \
! 113: }
! 114: # define GET_HDR_ADDR(p, ha) \
! 115: { \
! 116: register bottom_index * bi; \
! 117: \
! 118: GET_BI(p, bi); \
! 119: (ha) = &(HDR_FROM_BI(bi, p)); \
! 120: }
! 121: # define GET_HDR(p, hhdr) { register hdr ** _ha; GET_HDR_ADDR(p, _ha); \
! 122: (hhdr) = *_ha; }
! 123: # define SET_HDR(p, hhdr) { register hdr ** _ha; GET_HDR_ADDR(p, _ha); \
! 124: *_ha = (hhdr); }
! 125: # define HDR(p) GC_find_header((ptr_t)(p))
! 126: # endif
! 127:
! 128: /* Is the result a forwarding address to someplace closer to the */
! 129: /* beginning of the block or NIL? */
! 130: # define IS_FORWARDING_ADDR_OR_NIL(hhdr) ((unsigned long) (hhdr) <= MAX_JUMP)
! 131:
! 132: /* Get an HBLKSIZE aligned address closer to the beginning of the block */
! 133: /* h. Assumes hhdr == HDR(h) and IS_FORWARDING_ADDR(hhdr). */
! 134: # define FORWARDED_ADDR(h, hhdr) ((struct hblk *)(h) - (unsigned long)(hhdr))
! 135: # endif /* GC_HEADERS_H */
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