Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!seismo!lll-crg!rutgers!sri-unix!garth!kissell From: kissell@garth.UUCP (Kevin Kissell) Newsgroups: comp.arch Subject: Re: How does compiled code use the floa Message-ID: <393@garth.UUCP> Date: Thu, 18-Dec-86 02:39:00 EST Article-I.D.: garth.393 Posted: Thu Dec 18 02:39:00 1986 Date-Received: Thu, 18-Dec-86 20:48:31 EST References: <394@houxs.UUCP> <165100001@uiucdcsb> Sender: Reply-To: kissell@garth.UUCP (Kevin Kissell) Organization: Fairchild Semiconductor (APD) -- Palo Alto, CA Lines: 22 In article <165100001@uiucdcsb> robison@uiucdcsb.cs.uiuc.edu writes: > >I've heard of another scheme, but never tried it: > >Code generation emits a call to a floating point library. >If the FP hardware is available, the library routine changes >(at run time) the call instruction to the equivalent hardware >instruction. This way you pay for the subroutine linkage only >on the first call. The disadvantage is that self-modifying code >is not allowed on some architectures. One would not have that problem if one patched the program as it was brought into memory, rather than on the first library call. But I doubt that anyone really wants to generate code that *assumes* that emulation libraries are in use. Kevin D. Kissell Fairchild Advanced Processor Division uucp: {ihnp4, decwrl, ucbvax}!hplabs!harvax!garth!kissell Disclaimer: All opinions expressed herein are either my own or a product of your imagination.