1993-03-31 13:22:17 +00:00
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.In
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1991-09-27 16:19:24 +00:00
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.NH
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INTRODUCTION
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.NH 2
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Why an EM backend for SPARC processors?
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.PP
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With the introduction of SPARC-based computers like the Sun-4, a
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whole new range of fast computers became readily available to the general
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public. The power of large mainframes had been captured into a small
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desk-top computer at only a fraction of the cost.
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.PP
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In the older days, a new computer used to be very hard to integrate into
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the existing environment, but due to standardization in the software world
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incompatibility in hardware no longer means incompatibility in software.
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Programs that are written for computer A can often be run on computer B
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without major modifications. Unfortunately this is not true for all software.
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.PP
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There will always be programs that rely on the specific
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hardware of a certain computer for many different reasons. They
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can be categorized as:
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.IP -
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poorly written programs
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.IP -
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programs to directly control hardware (device drivers)
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.IP -
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code that requires efficiency (time-critical I/O drivers)
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.IP -
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programs to generate code to run on the hardware (compilers)
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.LP
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This project for instance, the design and implementation of an EM backend
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for SPARC processors, comes in the last category.
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.PP
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We have designed and implemented an algorithm to convert EM programs to code
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that will run directly on the SPARC hardware. Henceforth, both the algorithm
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and the implementation will be referred to as the EM-to-SPARC backend,
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or simply: the backend.
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.NH 2
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Why has nobody done this before?
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.PP
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Since EM was designed around 1981 and even SPARC has been around for some
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years now, one may wonder why nobody has ever written an EM to SPARC backend
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before. The reason is twofold. In the first place, there are some
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non-trivial problems to be solved in the design phase, and secondly,
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the SPARC-design combined with the lack of documentation, would surely
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cost a lot of blood, sweat and tears. The absence of
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clues to any of the design problems, combined with the \(em at first
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glance \(em inhuman
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SPARC instruction set did not make this a very attractive project.
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.PP
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On the other hand, these were exactly the reasons which made us take on
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this particular project: it would require design skills, as well as some
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hard work; a golden combination for a successful project.
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.bp
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