diff options
Diffstat (limited to 'src/mem/cache/blk.hh')
| -rw-r--r-- | src/mem/cache/blk.hh | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/src/mem/cache/blk.hh b/src/mem/cache/blk.hh index 2b3a34bb8..a32edbf20 100644 --- a/src/mem/cache/blk.hh +++ b/src/mem/cache/blk.hh @@ -281,7 +281,7 @@ class CacheBlk /** * Pretty-print a tag, and interpret state bits to readable form - * including mapping to a MOESI stat. + * including mapping to a MOESI state. * * @return string with basic state information */ @@ -299,6 +299,17 @@ class CacheBlk * E 1 0 1 * S 0 0 1 * I 0 0 0 + * + * Note that only one cache ever has a block in Modified or + * Owned state, i.e., only one cache owns the block, or + * equivalently has the BlkDirty bit set. However, multiple + * caches on the same path to memory can have a block in the + * Exclusive state (despite the name). Exclusive means this + * cache has the only copy at this level of the hierarchy, + * i.e., there may be copies in caches above this cache (in + * various states), but there are no peers that have copies on + * this branch of the hierarchy, and no caches at or above + * this level on any other branch have copies either. **/ unsigned state = isWritable() << 2 | isDirty() << 1 | isValid(); char s = '?'; |