The example given for the use of histograms (https://software.intel.com/en-us/ipp-dev-reference-histogram) seems misleading. The upper limit is set to 255 and the criterion for an intensity to belong in a bin is stated to be <=<Therefore, if the randomized image contains the value 255, the sum of frequencies will not reach 64 = 8x8, which very much seems to be the intention of the example.
See the thread "ippiHistogram_8u_C1R problem" https://software.intel.com/en-us/forums/intel-integrated-performance-primitives/topic/676143 and my comment on it. There never was a reply.
Adriaan van Os