Xref: utzoo comp.lang.c++:2141 comp.lang.c:14413 comp.lang.forth:687 comp.lang.fortran:1554 comp.lang.misc:2226 comp.arch:7384 Path: utzoo!utgpu!watmath!clyde!att!rutgers!cs.utexas.edu!sm.unisys.com!ism780c!news From: news@ism780c.isc.com (News system) Newsgroups: comp.lang.c++,comp.lang.c,comp.lang.forth,comp.lang.fortran,comp.lang.misc,comp.arch Subject: Re: Assembly or .... Message-ID: <19848@ism780c.isc.com> Date: 30 Nov 88 04:28:08 GMT References: <1388@aucs.UUCP| <729@convex.UUCP> <1961@crete.cs.glasgow.ac.uk> <949@taux01.UUCP> <1034@l.cc.purdue.edu> Reply-To: marv@ism780.UUCP (Marvin Rubenstein) Organization: Interactive Systems Corp., Santa Monica CA Lines: 27 In article <1032@l.cc.purdue.edu> cik@l.cc.purdue.edu (Herman Rubin) writes: ... > suppose we want to >divide a by b, obtaining an integer result i and a remainder c. I know >of no machine with this instruction, and this is not that unusual an >instruction to demand. It is cheap in hardware, and extremely expensive >in software--at least 4 instructions. Then he clarifies: >I do not know if I made it clear in my initial posting, but the problem >arises if the types of a, b, and c are floating. Not that the quote from >my paper specifically has i an integer. >-- >Herman Rubin, Dept. of Statistics, Purdue Univ., West Lafayette IN47907 Ok here is one. Quoting from the IBM/709 Reference Manual (Circa 1959) FDH - Floating Divide or Halt THe c(ac) [means contents of ac register] are divided by c(y). The quotent appears in the mq and the remainder appears in the ac. ... I leave it to Herman to find out why more modern machines leave this out. Hint: Try profiling your aplication to see what percent of the total process time is used producing the remainder. Marv Rubinstein.