1. A method comprising: receiving a multiply instruction, the multiply instruction indicating source operands consisting of only a first source operand and a second source operand, wherein the first and second source operands have a same size; performing a multiply operation, including propagating carries, on the first and second source operands to generate a product of the first and second source operands; and storing a product of the first and second source operands in one or more destination operands indicated by the multiply instruction, wherein the one or more destination operands in which the product is stored have twice as many bits as each of the first and second source operands; and completing execution of the multiply instruction without writing a carry flag, wherein the multiply instruction is included in an instruction set with another multiply instruction that when performed is to cause updating of the carry flag dependent upon a corresponding product.