1. A method of executing a machine instruction in a transactional computing environment, said method comprising: obtaining, by a processor, the machine instruction for execution in the transactional computing environment, the machine instruction being defined for computer execution according to a computer architecture, the machine instruction comprising: an operation code field to be used to provide an operation code to specify a conditional instruction end operation; and executing, by the processor, the machine instruction, the executing comprising: obtaining an operand of the machine instruction, the operand comprising a sign value; determining whether the operand has a predetermined relationship with respect to a value, the predetermined relationship comprising equal and the value comprising zero; based on determining that the operand does not have the predetermined relationship with respect to the value, further determining whether the operand is greater than zero, and based on the operand being greater than zero, delaying completion of the machine instruction and repeating the obtaining and the determining, and based on the operand being less than zero, prematurely terminating the machine instruction; based on determining that the operand has the predetermined relationship with respect to the value, completing execution of the machine instruction; and wherein the obtaining the operand, the determining whether the operand has the predetermined relationship with respect to the value, the based on determining that the operand does not have the predetermined relationship with respect to the value, further determining whether the operand is greater than zero, and the based on determining that the operand has the predetermined relationship with respect to the value, completing execution of the machine instruction are performed as part of a single instruction having the operation code.