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From: bayes@hpislx.HP.COM (Scott Bayes)
Newsgroups: comp.sys.mac.programmer
Subject: Re: F Emulator, Just what the hey is it
Message-ID: <9710003@hpislx.HP.COM>
Date: 30 Aug 90 19:19:51 GMT
References: <1990Aug8.100755.1@mel.cipl.uiowa.edu>
Organization: Measurement Systems Operation - Loveland, CO
Lines: 16

One reason for not doing your software math through an F-line emulator
unless you have to:

It can be significantly slower than using stack or register-based calls
on the library.  Consider that to emulate an FMOVE, the exception needs
to be raised and processed, putting a lot of junk on the stack, the
stack then examined to see what was happening when the exception was
raised, that operation performed in emulation, then the stack cleaned up
with an RTE or facsimile.  Of course you haven't done any math yet,
you've only set up one of the operands.

Contrast this to 2 or 3 move.l instructions to register or stack
required to set up a floating argument for the library.

Scott Bayes
Hewlett-Packard Co