mem-cache: Fix BDI size calculation
The bitmask field indicates to which base a delta refers, and in
the original paper it is fixed and proportional to the highest
number of bases allowed in the compressed data.
Change-Id: I271bf2e19e0765de52b933eaf6d4fcc2ce25d185
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/19748
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>
diff --git a/src/mem/cache/compressors/bdi.cc b/src/mem/cache/compressors/bdi.cc
index e29179f..a8068c6 100644
--- a/src/mem/cache/compressors/bdi.cc
+++ b/src/mem/cache/compressors/bdi.cc
@@ -166,7 +166,7 @@
std::size_t size = encodingBits;
// Number of bits used by BitMask
- size += bitMask.size()*std::ceil(std::log2(bases.size()));
+ size += bitMask.size()*std::ceil(std::log2(maxNumBases));
// Number of bits used by Bases. bases[0] is implicit in a hardware
// implementation, therefore its size is 0
