A processor is provided with a register file comprising a plurality of vector registers, and an execution core coupled to the register file, where the execution core is configured to execute a set of checksum instructions with a first checksum instruction to specify a first vector operand, a second vector operand, and a result vector operand, where the first vector operand is in a first vector register of the plurality of vector registers, the second vector operand is in a second register of the plurality of vector registers, and the result vector operand is to be written to a third vector register of the plurality of vector registers, and to execute the first checksum instruction, the execution core is configured to accumulate bytes from the first vector operand and the second vector operand into a first portion of the result vector operand and add the accumulated bytes from the first vector operand and the second vector operand to a second portion of the result vector operand to generate the second portion written to the result vector operand.