1. A general-purpose computer system having a memory, but no vector registers, comprising: instruction control means responsive to a list vector instruction for providing an increment value of a list vector, an initial address of a second operand vector, an increment value of a first operand vector, an initial address of said list vector and an initial address of a first operand vector; a first register for storing said increment value of a list vector; a second register for storing an increment value of a second operand vector; a third register for storing said initial address of the second operand vector; a fourth register for storing said increment value of a first operand vector; a fifth register for storing a fetch data address, the initial value of which is said initial address of said list vector; a sixth register for storing a store data address, the initial value of which is said initial address of the first operand vector; first adding means for adding the value stored in said first register to the fetch data address stored in said fifth register and for storing as a fetch data address the result of addition representative of an address of the list vector into said fifth register; second adding means for adding the value stored in said second register to a value stored in said third register; third adding means for adding the value stored in said fourth register to the store data address stored in said sixth register and for storing as a store data address the result of addition representative of an address of the first operand vector into said sixth register; bit shift means for performing bit shifting of an element of the list vector read out from said memory in response to the fetch data address stored in said fifth register and for storing a value resulting from the bit shift into said second register; and memory control means for (i) reading out elements of the list vector from said memory at addresses determined by said first adding means adding sequentially values stored in said first register to the fetch data address stored in said fifth register for storing said read-out elements into said second register after bit shift thereof by said bit shift means, and (ii) reading out elements of the second operand vector from the memory at addresses determined by a value obtained by adding sequentially values stored in said second register to the initial address of the second operand vector stored in said third register by said second adding means and for storing said second operand vector elements into memory locations designated by addresses determined by adding sequentially values stored in said fourth register to an address of the first operand vector stored in said sixth register by said third adding means; whereby a list operation specified by a list vector instruction can be executed in which the number of an element of the second operand vector is represented by an element of the list vector.