> Finally, ISTR, but can find no references, that FORTRAN II had > a two argument SGNF(X,Y) defined as the magnitude of X with the > sign of Y. A plausible motivation is this was a single machine > instruction on the IBM 70x series -- doubleword shift with a > count of zero.
The SIGN function is still in Fortran, along with the more specific functions ISIGN and DSIGN (for integer and double precision). (Fortran II function names had to end in F, a restriction removed for Fortran IV and the ANSI Fortran 66 version.) (Newer standards include the effect when X is zero on machines supporting a negative floating point zero.) The arithmetic IF is still in Fortran, though its use is discourage and it is, I believe, on the obsolescence list. -- glen
