On Wednesday, 16 August 2017 at 14:04:47 -0400, Paul Winalski wrote: I think there's some doubt about those statements. The 704 was introduced in 1954, and FORTRAN didn't appear until late 1956 or 1957. That's a long time in the history of computing. I think the arithmetic IF was put into FORTRAN because it was easy to implement with the CAS instruction. It doesn't make much sense from a mathematical point of view. Looking at the assembly listings of the FORTRAN II compiler (http://www.softwarepreservation.org/projects/FORTRAN/source/fortran-ii/fort…, mentioned by Paul McJones), a typical use of CAS is followed by two unconditional TRA (transfer) instructions and further code, though presumably early FORTRAN compilers would not optimize in this way. Timing includes loading an operand from memory. The conditional transfer instructions are based on accumulator contents, so you'd need to perform some arithmetic operation first, in the process possibly destroying accumulator contents that you want. Doubtless you're right in some (many) cases, but my guess is that the authors of FORTRAN were looking for the cheapest solution, not the fastest one. For decades to come, the fastest solution was assembler. Greg -- Sent from my desktop computer. Finger grog(a)lemis.com for PGP public key. See complete headers for address and phone numbers. This message is digitally signed. If your Microsoft mail program reports problems, please read http://lemis.com/broken-MUA