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emacs/mps/code/bt.c
Richard Brooksby 3d5e2ca85f Adding hopenames back into the master sources, so that they can be included in the union sources along with the id keywords.
This was achieved by partially undoing changelist 24817, including an accidental corruption of eventgen.pl.

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C

/* impl.c.bt: BIT TABLES
*
* $Id$
* $HopeName: MMsrc!bt.c(trunk.25) $
* Copyright (c) 2001 Ravenbrook Limited.
*
* READERSHIP
*
* .readership: Any MPS developer
*
* DESIGN
*
* .design: see design.mps.bt
*/
#include "mpm.h"
SRCID(bt, "$Id$");
/* BTIndexAlignUp, BTIndexAlignDown -- Align bit-table indices
*
* Align bit-table indices up and down to word boundaries
*/
#define BTIndexAlignUp(index) (IndexAlignUp((index), MPS_WORD_WIDTH))
#define BTIndexAlignDown(index) (IndexAlignDown((index), MPS_WORD_WIDTH))
/* BTMask -- generate sub-word masks
*
* Create a mask with only specified bits set
*/
/* Return a word mask of bits set only from base and above */
#define BTMaskLow(base) (~(Word)0 << (base))
/* Return a word mask of bits set only below limit */
#define BTMaskHigh(limit) (~(Word)0 >> (MPS_WORD_WIDTH - (limit)))
/* Return a word mask of bits set only in requested range */
#define BTMask(base,limit) (BTMaskHigh((limit)) & BTMaskLow((base)))
/* BTWordIndex, BTBitIndex -- Decode BT indexes
*
* Return word and bit indexes from index
*/
#define BTWordIndex(index) ((index) >> MPS_WORD_SHIFT)
#define BTBitIndex(index) ((index) & (MPS_WORD_WIDTH - 1))
/* BTIsSmallRange -- test range size
*
* Predicate to determine whether a range is sufficiently small
* that it's not worth trying to separate words and odd bits.
* The choice of what counts as "sufficiently small" is made
* for efficiency reasons. Empirical evidence indicates that
* a good choice is ranges of size 6 or less.
*/
#define BTIsSmallRange(base,limit) ((base) + 6 >= (limit))
/* ACT_ON_RANGE -- macro to act on a base-limit range
*
* Three actions should be provided:
* - single_action(btIndex) - operates on a single bit
* - bits_action(wordIndex, base, limit) -- operates on part-words
* - word_action(wordIndex) -- Operates on full words in range
* WORD_ACTIONs should not use break or continue.
*
* If the range is small enough it will be processed a single
* bit at a time. Larger ranges are processed as words where
* possible, and part-words for boundary bits.
*/
#define ACT_ON_RANGE(base,limit,single_action, \
bits_action,word_action) \
BEGIN \
if (BTIsSmallRange((base), (limit))) { \
/* Small ranges are processed most efficiently bit-by-bit */ \
Index actBit; \
for (actBit = (base); actBit < (limit); ++actBit) { \
single_action(actBit); \
} \
} else { \
Index actInnerBase = BTIndexAlignUp((base)); \
if (actInnerBase > (limit)) { /* no inner range */ \
AVER((base) < (limit)); /* caught by small range case */ \
bits_action(BTWordIndex((base)), \
BTBitIndex((base)), \
BTBitIndex((limit))); \
} else { \
Index actInnerLimit = BTIndexAlignDown((limit)); \
Index actWordIndex, actWordBase, actWordLimit; \
\
actWordBase = BTWordIndex(actInnerBase); \
actWordLimit = BTWordIndex(actInnerLimit); \
\
if ((base) < actInnerBase) { \
bits_action(actWordBase-1, \
BTBitIndex((base)), \
MPS_WORD_WIDTH); \
} \
\
for (actWordIndex = actWordBase; actWordIndex < actWordLimit; \
++actWordIndex) { \
word_action(actWordIndex); \
} \
\
if ((limit) > actInnerLimit) { \
bits_action(actWordLimit, 0, BTBitIndex((limit))); \
} \
} \
} \
END
/* ACT_ON_RANGE_HIGH -- macro to act on a base-limit range
*
* in reverse order. Usage as for ACT_ON_RANGE
*/
#define ACT_ON_RANGE_HIGH(base,limit,single_action, \
bits_action,word_action) \
BEGIN \
if (BTIsSmallRange((base), (limit))) { \
/* Small ranges are processed most efficiently bit-by-bit */ \
Index actBit; \
for (actBit = (limit); actBit > (base); --actBit) { \
single_action(actBit - 1); \
} \
} else { \
Index actInnerBase = BTIndexAlignUp((base)); \
if (actInnerBase > (limit)) { /* no inner range */ \
AVER((base) < (limit)); /* caught by small range case */ \
bits_action(BTWordIndex((base)), \
BTBitIndex((base)), \
BTBitIndex((limit))); \
} else { \
Index actInnerLimit = BTIndexAlignDown((limit)); \
Index actWordIndex, actWordBase, actWordLimit; \
\
actWordBase = BTWordIndex(actInnerBase); \
actWordLimit = BTWordIndex(actInnerLimit); \
\
if ((limit) > actInnerLimit) { \
bits_action(actWordLimit, 0, BTBitIndex((limit))); \
} \
\
for (actWordIndex = actWordLimit; actWordIndex > actWordBase; \
--actWordIndex) { \
word_action(actWordIndex-1); \
} \
\
if ((base) < actInnerBase) { \
bits_action(actWordBase-1, \
BTBitIndex((base)), \
MPS_WORD_WIDTH); \
} \
} \
} \
END
/* BTCreate -- allocate a BT from the control pool
*
* See design.mps.bt.if.create
*/
Res BTCreate(BT *btReturn, Arena arena, Count length)
{
Res res;
BT bt;
void *p;
AVER(btReturn != NULL);
AVERT(Arena, arena);
AVER(length > 0);
res = ControlAlloc(&p, arena, BTSize(length),
/* withReservoirPermit */ FALSE);
if (res != ResOK)
return res;
bt = (BT)p;
*btReturn = bt;
return ResOK;
}
/* BTDestroy -- free a BT to the control pool.
*
* See design.mps.bt.if.destroy
*/
void BTDestroy(BT bt, Arena arena, Count length)
{
AVER(bt != NULL);
AVERT(Arena, arena);
AVER(length > 0);
ControlFree(arena, bt, BTSize(length));
}
/* BTCheck -- check the validity of a bit table
*
* There's not much that can be checked at present. This is
* discussed in review.impl.c.bt.4.
*/
static Bool BTCheck(BT bt)
{
AVER(bt != NULL);
AVER(AddrIsAligned((Addr)bt, sizeof(Word)));
return TRUE;
}
/* BTSize -- return the size of a BT
*
* See design.mps.bt.fun.size
*/
size_t (BTSize)(unsigned long n)
{
/* check that the expression used in rounding up doesn't overflow */
AVER(n+MPS_WORD_WIDTH-1 > n);
return BTSize(n);
}
/* BTGet -- get a bit from a BT
*
* See design.mps.bt.fun.get
*/
Bool (BTGet)(BT t, Index i)
{
AVER(BTCheck(t));
/* Can't check i */
/* see macro in impl.h.mpm */
return BTGet(t, i);
}
/* BTSet -- set a bit in a BT
*
* See design.mps.bt.fun.set
*/
void (BTSet)(BT t, Index i)
{
AVER(BTCheck(t));
/* Can't check i */
/* see macro in impl.h.mpm */
BTSet(t, i);
}
/* BTRes -- reset a bit in a BT
*
* design.mps.bt.fun.res
*/
void (BTRes)(BT t, Index i)
{
AVER(BTCheck(t));
/* Can't check i */
/* see macro in impl.h.mpm */
BTRes(t, i);
}
/* BTSetRange -- set a range of bits in a BT
*
* design.mps.bt.fun.set-range
*/
void BTSetRange(BT t, Index base, Index limit)
{
AVER(BTCheck(t));
AVER(base < limit);
#define SINGLE_SET_RANGE(i) \
BTSet(t, (i))
#define BITS_SET_RANGE(i,base,limit) \
t[(i)] |= BTMask((base),(limit))
#define WORD_SET_RANGE(i) \
t[(i)] = ~(Word)(0)
ACT_ON_RANGE(base, limit, SINGLE_SET_RANGE,
BITS_SET_RANGE, WORD_SET_RANGE);
}
/* BTIsResRange -- test whether a range of bits is all reset
*
* See design.mps.bt.fun.is-reset-range.
*/
Bool BTIsResRange(BT bt, Index base, Index limit)
{
AVER(BTCheck(bt));
AVER(base < limit);
/* Can't check range of base or limit */
#define SINGLE_IS_RES_RANGE(i) \
if (BTGet(bt, (i))) return FALSE
#define BITS_IS_RES_RANGE(i,base,limit) \
if ((bt[(i)] & BTMask((base),(limit))) != (Word)0) return FALSE
#define WORD_IS_RES_RANGE(i) \
if (bt[(i)] != (Word)0) return FALSE
ACT_ON_RANGE(base, limit, SINGLE_IS_RES_RANGE,
BITS_IS_RES_RANGE, WORD_IS_RES_RANGE);
return TRUE;
}
/* BTIsSetRange -- test whether a range of bits is all set
*
* See design.mps.bt.fun.is-set-range.
*/
Bool BTIsSetRange(BT bt, Index base, Index limit)
{
AVER(BTCheck(bt));
AVER(base < limit);
/* Can't check range of base or limit */
#define SINGLE_IS_SET_RANGE(i) \
if (!BTGet(bt, (i))) return FALSE
#define BITS_IS_SET_RANGE(i,base,limit) \
BEGIN \
Word bactMask = BTMask((base),(limit)); \
if ((bt[(i)] & bactMask) != bactMask) \
return FALSE; \
END
#define WORD_IS_SET_RANGE(i) \
if (bt[(i)] != ~(Word)0) return FALSE
ACT_ON_RANGE(base, limit, SINGLE_IS_SET_RANGE,
BITS_IS_SET_RANGE, WORD_IS_SET_RANGE);
return TRUE;
}
/* BTResRange -- reset a range of bits in a BT
*
* design.mps.bt.fun.res-range
*/
void BTResRange(BT t, Index base, Index limit)
{
AVER(BTCheck(t));
AVER(base < limit);
#define SINGLE_RES_RANGE(i) \
BTRes(t, (i))
#define BITS_RES_RANGE(i,base,limit) \
t[(i)] &= ~(BTMask((base),(limit)))
#define WORD_RES_RANGE(i) t[(i)] = (Word)(0)
ACT_ON_RANGE(base, limit, SINGLE_RES_RANGE,
BITS_RES_RANGE, WORD_RES_RANGE);
}
/* BTFindSet -- find the lowest set bit in a range in a bit table.
*
* Sets foundReturn to false if the range is entirely reset;
* in this case indexReturn is unset. Sets foundReturn to true
* otherwise.
*
* Implemented as a macro for efficiency reasons.
* The macro internally uses the label btFindSetLabel.
* If the macro must be used more than once within a function
* this label must be redefined to avoid a nameclash. E.g.
* #define btFindSetLabel uniqueLabel
* BTFindSet(...)
* #undef btFindSetLabel
*/
#define BTFindSet(foundReturn,indexReturn,bt,base,limit)\
BEGIN \
Bool *bfsFoundReturn = (foundReturn); \
Index *bfsIndexReturn = (indexReturn); \
BT bfsBt = (bt); \
ACT_ON_RANGE((base), (limit), SINGLE_FIND_SET, \
BITS_FIND_SET, WORD_FIND_SET); \
*bfsFoundReturn = FALSE; \
btFindSetLabel:; \
END
#define SINGLE_FIND_SET(i) \
if (BTGet(bfsBt, (i))) { \
*bfsIndexReturn = (i); \
*bfsFoundReturn = TRUE; \
goto btFindSetLabel; \
}
#define BITS_FIND_SET(wi,base,limit) \
BEGIN \
Index bactWi = (wi); \
ACTION_FIND_SET(bactWi, bfsBt[bactWi], (base), (limit)); \
END
#define WORD_FIND_SET(wi) \
BEGIN \
Index wactWi = (wi); \
ACTION_FIND_SET(wactWi, bfsBt[wactWi], 0, MPS_WORD_WIDTH); \
END
#define ACTION_FIND_SET(wi,word,base,limit) \
ACTION_FIND_SET_BIT((wi),(word),(base),(limit),btFindSetLabel)
/* ACTION_FIND_SET_BIT -- Find first set bit in a range
*
* Helper macro to find the low bit in a range of a word.
* Works by first shifting the base of the range to the low
* bits of the word. Then loops performing a binary chop
* over the data looking to see if a bit is set in the lower
* half. If not, it must be in the upper half which is then
* shifted down. The loop completes after using a chop unit
* of a single single bit.
*/
#define ACTION_FIND_SET_BIT(wi,word,base,limit,label) \
BEGIN \
/* no need to mask the low bits which are shifted */ \
Index actionIndex = (base); \
Word actionWord = ((word) & BTMaskHigh((limit))) >> actionIndex; \
Count actionMaskWidth = (MPS_WORD_WIDTH >> 1); \
Word actionMask = ~(Word)0 >> (MPS_WORD_WIDTH-actionMaskWidth); \
if (actionWord != (Word)0) { \
while (actionMaskWidth != (Count)0) { \
if ((actionWord & actionMask) == (Word)0) { \
actionIndex += actionMaskWidth; \
actionWord >>= actionMaskWidth; \
} \
actionMaskWidth >>= 1; \
actionMask >>= actionMaskWidth; \
} \
*bfsIndexReturn = ((wi) << MPS_WORD_SHIFT) | actionIndex; \
*bfsFoundReturn = TRUE; \
goto label; \
} \
END
/* BTFindRes -- find the lowest reset bit in a range in a bit table.
*
* Usage as for BTFindSet
*
* Internally uses the label btFindResLabel
* which must be redefined to avoid a nameclash if the macro is
* used twice in a function scope.
*/
#define BTFindRes(foundReturn,indexReturn,bt,base,limit)\
BEGIN \
Bool *bfsFoundReturn = (foundReturn); \
Index *bfsIndexReturn = (indexReturn); \
BT bfsBt = (bt); \
ACT_ON_RANGE((base), (limit), SINGLE_FIND_RES, \
BITS_FIND_RES, WORD_FIND_RES); \
*bfsFoundReturn = FALSE; \
btFindResLabel:; \
END
#define SINGLE_FIND_RES(i) \
if (!BTGet(bfsBt, (i))) { \
*bfsIndexReturn = (i); \
*bfsFoundReturn = TRUE; \
goto btFindResLabel; \
}
#define BITS_FIND_RES(wi,base,limit) \
BEGIN \
Index bactWi = (wi); \
ACTION_FIND_RES(bactWi,bfsBt[bactWi], (base), (limit)); \
END
#define WORD_FIND_RES(wi) \
BEGIN \
Index wactWi = (wi); \
ACTION_FIND_RES(wactWi, bfsBt[wactWi], 0, MPS_WORD_WIDTH); \
END
#define ACTION_FIND_RES(wi,word,base,limit) \
ACTION_FIND_SET_BIT((wi),~(word),(base),(limit),btFindResLabel)
/* BTFindSetHigh -- find the highest set bit in a range in a bit table.
*
* Usage as for BTFindSet
*
* Internally uses the label btFindSetHighLabel
* which must be redefined to avoid a nameclash if the macro is
* used twice in a function scope.
*/
#define BTFindSetHigh(foundReturn,indexReturn,bt,base,limit)\
BEGIN \
Bool *bfsFoundReturn = (foundReturn); \
Index *bfsIndexReturn = (indexReturn); \
BT bfsBt = (bt); \
ACT_ON_RANGE_HIGH((base), (limit), SINGLE_FIND_SET_HIGH, \
BITS_FIND_SET_HIGH, WORD_FIND_SET_HIGH); \
*bfsFoundReturn = FALSE; \
btFindSetHighLabel:; \
END
#define SINGLE_FIND_SET_HIGH(i) \
if (BTGet(bfsBt, (i))) { \
*bfsIndexReturn = (i); \
*bfsFoundReturn = TRUE; \
goto btFindSetHighLabel; \
}
#define BITS_FIND_SET_HIGH(wi,base,limit) \
BEGIN \
Index bactWi = (wi); \
ACTION_FIND_SET_HIGH(bactWi, bfsBt[bactWi], (base), (limit)); \
END
#define WORD_FIND_SET_HIGH(wi) \
BEGIN \
Index wactWi = (wi); \
ACTION_FIND_SET_HIGH(wactWi, (bfsBt[wactWi]), 0, MPS_WORD_WIDTH); \
END
#define ACTION_FIND_SET_HIGH(wi,word,base,limit) \
ACTION_FIND_SET_BIT_HIGH((wi),(word),(base),(limit),btFindSetHighLabel)
/* ACTION_FIND_SET_BIT_HIGH -- Find highest set bit in a range
*
* Helper macro to find the high bit in a range of a word.
* Essentially a mirror image of ACTION_FIND_SET
*/
#define ACTION_FIND_SET_BIT_HIGH(wi,word,base,limit,label) \
BEGIN \
/* no need to mask the high bits which are shifted */ \
Index actionShift = MPS_WORD_WIDTH - (limit); \
Index actionIndex = MPS_WORD_WIDTH - 1 - actionShift; \
Word actionWord = ((word) & BTMaskLow((base))) << actionShift; \
Count actionMaskWidth = (MPS_WORD_WIDTH >> 1); \
Word actionMask = ~(Word)0 << (MPS_WORD_WIDTH-actionMaskWidth); \
if (actionWord != (Word)0) { \
while (actionMaskWidth != (Count)0) { \
if ((actionWord & actionMask) == (Word)0) { \
actionIndex -= actionMaskWidth; \
actionWord <<= actionMaskWidth; \
} \
actionMaskWidth >>= 1; \
actionMask <<= actionMaskWidth; \
} \
*bfsIndexReturn = ((wi) << MPS_WORD_SHIFT) | actionIndex; \
*bfsFoundReturn = TRUE; \
goto label; \
} \
END
/* BTFindResHigh -- find the highest reset bit in a range
*
* Usage as for BTFindSet
*
* Internally uses the label btFindSetHighLabel
* which must be redefined to avoid a nameclash if the macro is
* used twice in a function scope.
*/
#define BTFindResHigh(foundReturn,indexReturn,bt,base,limit)\
BEGIN \
Bool *bfsFoundReturn = (foundReturn); \
Index *bfsIndexReturn = (indexReturn); \
BT bfsBt = (bt); \
ACT_ON_RANGE_HIGH((base), (limit), SINGLE_FIND_RES_HIGH, \
BITS_FIND_RES_HIGH, WORD_FIND_RES_HIGH); \
*bfsFoundReturn = FALSE; \
btFindResHighLabel:; \
END
#define SINGLE_FIND_RES_HIGH(i) \
if (!BTGet(bfsBt, (i))) { \
*bfsIndexReturn = (i); \
*bfsFoundReturn = TRUE; \
goto btFindResHighLabel; \
}
#define BITS_FIND_RES_HIGH(wi,base,limit) \
BEGIN \
Index bactWi = (wi); \
ACTION_FIND_RES_HIGH(bactWi, bfsBt[bactWi], (base), (limit)); \
END
#define WORD_FIND_RES_HIGH(wi) \
BEGIN \
Index wactWi = (wi); \
ACTION_FIND_RES_HIGH(wactWi, (bfsBt[wactWi]), 0, MPS_WORD_WIDTH); \
END
#define ACTION_FIND_RES_HIGH(wi,word,base,limit) \
ACTION_FIND_SET_BIT_HIGH((wi),~(word),(base),(limit),btFindResHighLabel)
/* BTFindResRange -- find a reset range of bits in a bit table
*
* Starts searching at the low end of the search range.
*
* See design.mps.bt.fun.find-res-range.
*/
static Bool BTFindResRange(Index *baseReturn, Index *limitReturn,
BT bt,
Index searchBase, Index searchLimit,
unsigned long minLength, unsigned long maxLength)
{
Bool foundRes; /* true if a reset bit is found */
Index resBase; /* base of a candidate reset range */
Index unseenBase; /* base of testing so far */
Index minLimit; /* limit of minimal acceptable range */
Index resLimit; /* limit of search for a candidate range */
AVER(baseReturn != NULL);
AVER(limitReturn != NULL);
AVERT(BT, bt);
AVER(searchBase < searchLimit);
AVER(minLength > 0);
AVER(minLength <= maxLength);
AVER(maxLength <= searchLimit - searchBase);
foundRes = FALSE; /* don't know first reset bit */
minLimit = 0; /* avoid spurious compiler warning */
resBase = searchBase; /* haven't seen anything yet */
unseenBase = searchBase; /* haven't seen anything yet */
resLimit = searchLimit - minLength + 1;
while (resBase < resLimit) {
Index setIndex; /* index of last set bit found */
Bool foundSet = FALSE; /* true if a set bit is found */
/* Find the first reset bit if it's not already known */
if (!foundRes) {
BTFindRes(&foundRes, &resBase, bt, unseenBase, resLimit);
if (!foundRes) {
/* failure */
return FALSE;
}
unseenBase = resBase + 1;
minLimit = resBase + minLength;
}
/* Look to see if there is any set bit in the minimum range */
BTFindSetHigh(&foundSet, &setIndex, bt, unseenBase, minLimit);
if (!foundSet) {
/* Found minimum range. Extend it. */
Index setBase; /* base of search for set bit */
Index setLimit; /* limit search for set bit */
foundSet = FALSE;
setBase = minLimit;
setLimit = resBase + maxLength;
if (setLimit > searchLimit)
setLimit = searchLimit;
if (setLimit > setBase)
BTFindSet(&foundSet, &setIndex, bt, setBase, setLimit);
if (!foundSet)
setIndex = setLimit;
AVER(setIndex - resBase >= minLength);
AVER(setIndex - resBase <= maxLength);
*baseReturn = resBase;
*limitReturn = setIndex;
return TRUE;
} else {
/* Range was too small. Try again */
unseenBase = minLimit;
resBase = setIndex + 1;
if (resBase != minLimit) {
/* Already found the start of next candidate range */
minLimit = resBase + minLength;
} else {
foundRes = FALSE;
}
}
}
/* failure */
return FALSE;
}
/* BTFindResRangeHigh -- find a reset range of bits in a bit table
*
* Starts searching at the high end of the search range.
*
* See design.mps.bt.fun.find-res-range.
*/
static Bool BTFindResRangeHigh(Index *baseReturn, Index *limitReturn,
BT bt,
Index searchBase, Index searchLimit,
unsigned long minLength,
unsigned long maxLength)
{
Bool foundRes; /* true if a reset bit is found */
Index resLimit; /* limit of a candidate reset range */
Index resIndex; /* index of highest reset bit found */
Index unseenLimit; /* limit of testing so far */
Index minBase; /* base of minimal acceptable range */
Index resBase; /* base of search for a candidate range */
AVER(baseReturn != NULL);
AVER(limitReturn != NULL);
AVERT(BT, bt);
AVER(searchBase < searchLimit);
AVER(minLength > 0);
AVER(minLength <= maxLength);
AVER(maxLength <= searchLimit - searchBase);
foundRes = FALSE; /* don't know first reset bit */
minBase = 0; /* avoid spurious compiler warning */
resLimit = searchLimit; /* haven't seen anything yet */
unseenLimit = searchLimit; /* haven't seen anything yet */
resBase = searchBase + minLength -1;
while (resLimit > resBase) {
Index setIndex; /* index of first set bit found */
Bool foundSet = FALSE; /* true if a set bit is found */
/* Find the first reset bit if it's not already known */
if (!foundRes) {
/* Look for the limit of a range */
BTFindResHigh(&foundRes, &resIndex, bt, resBase, unseenLimit);
if (!foundRes) {
/* failure */
return FALSE;
}
resLimit = resIndex + 1;
unseenLimit = resIndex;
minBase = resLimit - minLength;
}
/* Look to see if there is any set bit in the minimum range */
BTFindSet(&foundSet, &setIndex, bt, minBase, unseenLimit);
if (!foundSet) {
/* Found minimum range. Extend it. */
Index setBase; /* base of search for set bit */
Index setLimit; /* limit search for set bit */
Index baseIndex; /* base of reset range found */
foundSet = FALSE;
setLimit = minBase;
if ((searchBase + maxLength) > resLimit)
setBase = searchBase;
else
setBase = resLimit - maxLength;
if (setLimit > setBase)
BTFindSetHigh(&foundSet, &setIndex, bt, setBase, setLimit);
if (foundSet)
baseIndex = setIndex+1;
else
baseIndex = setBase;
AVER(resLimit - baseIndex >= minLength);
AVER(resLimit - baseIndex <= maxLength);
*baseReturn = baseIndex;
*limitReturn = resLimit;
return TRUE;
} else {
/* Range was too small. Try again */
unseenLimit = minBase;
resLimit = setIndex;
if (resLimit != minBase) {
/* Already found the start of next candidate range */
minBase = resLimit - minLength;
} else {
foundRes = FALSE;
}
}
}
/* failure */
return FALSE;
}
/* BTFindLongResRange -- find long range of reset bits in a bit table
*
* See design.mps.bt.fun.find-long-res-range.
*/
Bool BTFindLongResRange(Index *baseReturn, Index *limitReturn,
BT bt,
Index searchBase, Index searchLimit,
unsigned long length)
{
/* All parameters are checked by BTFindResRange. */
return BTFindResRange(baseReturn, limitReturn,
bt,
searchBase, searchLimit,
length, searchLimit - searchBase);
}
/* BTFindLongResRangeHigh -- find long range of reset bits in a bit table
*
* See design.mps.bt.fun.find-long-res-range-high.
*/
Bool BTFindLongResRangeHigh(Index *baseReturn, Index *limitReturn,
BT bt,
Index searchBase, Index searchLimit,
unsigned long length)
{
/* All parameters are checked by BTFindResRangeHigh. */
return BTFindResRangeHigh(baseReturn, limitReturn,
bt,
searchBase, searchLimit,
length, searchLimit - searchBase);
}
/* BTFindShortResRange -- find short range of reset bits in a bit table
*
* See design.mps.bt.fun.find-short-res-range.
*/
Bool BTFindShortResRange(Index *baseReturn, Index *limitReturn,
BT bt,
Index searchBase, Index searchLimit,
unsigned long length)
{
/* All parameters are checked by BTFindResRange. */
return BTFindResRange(baseReturn, limitReturn,
bt,
searchBase, searchLimit,
length, length);
}
/* BTFindShortResRangeHigh -- find short range of reset bits in a bit table
*
* Starts looking from the top of the search range.
*
* See design.mps.bt.fun.find-short-res-range-high.
*/
Bool BTFindShortResRangeHigh(Index *baseReturn, Index *limitReturn,
BT bt,
Index searchBase, Index searchLimit,
unsigned long length)
{
/* All parameters are checked by BTFindResRangeHigh. */
return BTFindResRangeHigh(baseReturn, limitReturn,
bt,
searchBase, searchLimit,
length, length);
}
/* BTRangesSame -- check that a range of bits in two BTs are the same.
*
* See design.mps.bt.if.ranges-same
*/
Bool BTRangesSame(BT comparand, BT comparator, Index base, Index limit)
{
AVER(BTCheck(comparand));
AVER(BTCheck(comparator));
AVER(base < limit);
#define SINGLE_RANGES_SAME(i) \
if (BTGet(comparand, (i)) != BTGet(comparator, (i))) \
return FALSE
#define BITS_RANGES_SAME(i,base,limit) \
BEGIN \
Index bactI = (i); \
Word bactMask = BTMask((base),(limit)); \
if ((comparand[bactI] & (bactMask)) != \
(comparator[bactI] & (bactMask))) \
return FALSE; \
END
#define WORD_RANGES_SAME(i) \
BEGIN \
Index wactI = (i); \
if ((comparand[wactI]) != (comparator[wactI])) \
return FALSE; \
END
ACT_ON_RANGE(base, limit, SINGLE_RANGES_SAME,
BITS_RANGES_SAME, WORD_RANGES_SAME);
return TRUE;
}
/* BTCopyInvertRange -- copy a range of bits from one BT to another,
* inverting them as you go.
*
* See design.mps.bt.if.copy-invert-range
*/
void BTCopyInvertRange(BT fromBT, BT toBT, Index base, Index limit)
{
AVER(BTCheck(fromBT));
AVER(BTCheck(toBT));
AVER(fromBT != toBT);
AVER(base < limit);
#define SINGLE_COPY_INVERT_RANGE(i) \
if (BTGet(fromBT, (i))) \
BTRes(toBT, (i)); \
else \
BTSet(toBT, (i))
#define BITS_COPY_INVERT_RANGE(i,base,limit) \
BEGIN \
Index bactI = (i); \
Word bactMask = BTMask((base),(limit)); \
toBT[bactI] = \
(toBT[bactI] & ~bactMask) | (~fromBT[bactI] & bactMask); \
END
#define WORD_COPY_INVERT_RANGE(i) \
BEGIN \
Index wactI = (i); \
toBT[wactI] = ~fromBT[wactI]; \
END
ACT_ON_RANGE(base, limit, SINGLE_COPY_INVERT_RANGE,
BITS_COPY_INVERT_RANGE, WORD_COPY_INVERT_RANGE);
}
/* BTCopyRange -- copy a range of bits from one BT to another
*
* See design.mps.bt.if.copy-range
*/
void BTCopyRange(BT fromBT, BT toBT, Index base, Index limit)
{
AVER(BTCheck(fromBT));
AVER(BTCheck(toBT));
AVER(fromBT != toBT);
AVER(base < limit);
#define SINGLE_COPY_RANGE(i) \
if (BTGet(fromBT, (i))) \
BTSet(toBT, (i)); \
else \
BTRes(toBT, (i))
#define BITS_COPY_RANGE(i,base,limit) \
BEGIN \
Index bactI = (i); \
Word bactMask = BTMask((base),(limit)); \
toBT[bactI] = \
(toBT[bactI] & ~bactMask) | (fromBT[bactI] & bactMask); \
END
#define WORD_COPY_RANGE(i) \
BEGIN \
Index wactI = (i); \
toBT[wactI] = fromBT[wactI]; \
END
ACT_ON_RANGE(base, limit, SINGLE_COPY_RANGE,
BITS_COPY_RANGE, WORD_COPY_RANGE);
}
/* BTCopyOffsetRange -- copy a range of bits from one BT to an
* offset range in another BT
*
* .slow: Can't always use ACT_ON_RANGE because word alignment
* may differ for each range. We could try to be smart about
* detecting similar alignment - but we don't.
*
* See design.mps.bt.if.copy-offset-range
*/
void BTCopyOffsetRange(BT fromBT, BT toBT,
Index fromBase, Index fromLimit,
Index toBase, Index toLimit)
{
Index fromBit, toBit;
AVER(BTCheck(fromBT));
AVER(BTCheck(toBT));
AVER(fromBT != toBT);
AVER(fromBase < fromLimit);
AVER(toBase < toLimit);
AVER((fromLimit - fromBase) == (toLimit - toBase));
for (fromBit = fromBase, toBit = toBase;
fromBit < fromLimit;
++fromBit, ++toBit) {
if (BTGet(fromBT, fromBit))
BTSet(toBT, toBit);
else
BTRes(toBT, toBit);
}
}