Data processor and data processing method

Abstract

In a data processor for updating path metrics in Viterbi decoding, an ACS processing can be efficiently executed with small power consumption. An ACS processing unit obtains an updated path metric through an ACS processing on the basis of pre-update path metrics read from a memory. In the memory, two pre-update path metrics necessary for obtaining one updated path metric are stored in an even address and an odd address having common bits excluding the least significant bits, so that the two pre-update path metrics can be read through one access. In the first cycle, the ACS processing unit makes an access to the memory and obtains a first updated path metric through the ACS processing on the basis of the thus read two pre-update path metrics. In the second cycle, without making any access to the memory, the ACS processing unit obtains a second updated path metric through the ACS processing on the basis of the two pre-update path metrics read in the first cycle.