The IBM 360 had BCT back in 1964. Rumor had it that it was created for Fortran DO statements (“for-loops”), but IBM’s compiler never emitted it. “The BCT inst

The IBM 360 had BCT back in 1964. Rumor had it that it was created for Fortran DO statements (“for-loops”), but IBM’s compiler never emitted it. “The BCT instruction subtracts 1 from the value of the contents of the target register specified in the first argument. If the value in the target register after the subtraction is zero, no branch occurs. Otherwise the program branches to the specified address.”