On a Core 2 Duo T7200, the default code gives about 1.8 Mhash/s, and 4way is slower at 1.0 Mhash/s. It has 4 MB of L2 cache, so it is probably not a question of cache size, as suggested at some point.

Unfortunately, the code (from svn) no longer compiles on ARM, as it now has SSE intrinsics hardcoded. I have removed the -msse2 and -DFOURWAYSSE2 flags from the makefile, and it still produces errors like this

Code:

sha256.cpp:8:23: error: xmmintrin.h: No such file or directory
sha256.cpp:34: error: ‘__m128i’ does not name a type

but hopefully this is easy to fix.

I wrapped sha256.cpp in
#ifdef FOURWAYSSE2
#endif // FOURWAYSSE2

try it now.

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