diff options
| -rw-r--r-- | rts/sm/NonMoving.h | 24 |
1 files changed, 20 insertions, 4 deletions
diff --git a/rts/sm/NonMoving.h b/rts/sm/NonMoving.h index 0f9cfa0e48..fdeee19d96 100644 --- a/rts/sm/NonMoving.h +++ b/rts/sm/NonMoving.h @@ -161,13 +161,29 @@ INLINE_HEADER unsigned int nonmovingSegmentBlockSize(struct NonmovingSegment *se return 1 << seg->block_size; } -// How many blocks does the given segment contain? Also the size of the bitmap. -INLINE_HEADER unsigned int nonmovingSegmentBlockCount(struct NonmovingSegment *seg) +// How many blocks does a segment with the given block size have? +INLINE_HEADER unsigned int nonmovingBlockCount(uint8_t log_block_size) { - unsigned int sz = nonmovingSegmentBlockSize(seg); unsigned int segment_data_size = NONMOVING_SEGMENT_SIZE - sizeof(struct NonmovingSegment); segment_data_size -= segment_data_size % SIZEOF_VOID_P; - return segment_data_size / (sz + 1); + unsigned int blk_size = 1 << log_block_size; + // N.B. +1 accounts for the byte in the mark bitmap. + return segment_data_size / (blk_size + 1); +} + +// How many blocks does the given segment contain? Also the size of the bitmap. +INLINE_HEADER unsigned int nonmovingSegmentBlockCount(struct NonmovingSegment *seg) +{ + // We compute the overwhelmingly common size cases directly to avoid a very + // expensive integer division. + switch (seg->block_size) { + case 3: return nonmovingBlockCount(3); + case 4: return nonmovingBlockCount(4); + case 5: return nonmovingBlockCount(5); + case 6: return nonmovingBlockCount(6); + case 7: return nonmovingBlockCount(7); + default: return nonmovingBlockCount(seg->block_size); + } } // Get a pointer to the given block index |