1998-01-09 09:41:19 +03:00
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.\" $NetBSD: pxin4.n,v 1.2 1998/01/09 06:41:57 perry Exp $
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.\"
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1994-06-19 04:07:16 +04:00
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.\" Copyright (c) 1979 The Regents of the University of California.
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the University of
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.\" California, Berkeley and its contributors.
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)pxin4.n 5.2 (Berkeley) 4/17/91
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.\"
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.if !\n(xx .so tmac.p
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.nr H1 3
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.if n .ND
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.NH
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Conclusions
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.PP
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It is appropriate to consider,
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given the amount of time invested in rewriting the interpreter,
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whether the time was well spent, or whether a code-generator
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could have been written with an equivalent amount of effort.
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The Berkeley Pascal system is being modified to interface
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to the code generator of the portable C compiler with
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not much more work than was involved in rewritting
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.I px .
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However this compiler will probably not supercede the interpreter
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in an instructional environment as the
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necessary loading and assembly processes will slow the
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compilation process to a noticeable degree.
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This effect will be further exaggerated because
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student users spend more time in compilation than in execution.
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Measurements over the course of a quarter at Berkeley with a mixture
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of students from beginning programming to upper division compiler
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construction show that the amount of time in compilation exceeds the amount
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of time spent in the interpreter, the ratio being approximately 60/40.
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.PP
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A more promising approach might have been a throw-away code generator
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such as was done for the
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.SM
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WATFIV
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.NL
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system.
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However the addition of high-quality post-mortem and interactive
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debugging facilities become much more difficult to provide than
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in the interpreter environment.
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