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phoenix |
This directory contains the version 0.92 test release of the NetWinder
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Floating Point Emulator.
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The majority of the code was written by me, Scott Bambrough It is
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written in C, with a small number of routines in inline assembler
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where required. It was written quickly, with a goal of implementing a
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working version of all the floating point instructions the compiler
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emits as the first target. I have attempted to be as optimal as
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possible, but there remains much room for improvement.
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I have attempted to make the emulator as portable as possible. One of
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the problems is with leading underscores on kernel symbols. Elf
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kernels have no leading underscores, a.out compiled kernels do. I
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have attempted to use the C_SYMBOL_NAME macro wherever this may be
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important.
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Another choice I made was in the file structure. I have attempted to
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contain all operating system specific code in one module (fpmodule.*).
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All the other files contain emulator specific code. This should allow
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others to port the emulator to NetBSD for instance relatively easily.
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The floating point operations are based on SoftFloat Release 2, by
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John Hauser. SoftFloat is a software implementation of floating-point
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that conforms to the IEC/IEEE Standard for Binary Floating-point
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Arithmetic. As many as four formats are supported: single precision,
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double precision, extended double precision, and quadruple precision.
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All operations required by the standard are implemented, except for
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conversions to and from decimal. We use only the single precision,
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double precision and extended double precision formats. The port of
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SoftFloat to the ARM was done by Phil Blundell, based on an earlier
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port of SoftFloat version 1 by Neil Carson for NetBSD/arm32.
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The file README.FPE contains a description of what has been implemented
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so far in the emulator. The file TODO contains a information on what
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remains to be done, and other ideas for the emulator.
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Bug reports, comments, suggestions should be directed to me at
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. General reports of "this program doesn't
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work correctly when your emulator is installed" are useful for
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determining that bugs still exist; but are virtually useless when
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attempting to isolate the problem. Please report them, but don't
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expect quick action. Bugs still exist. The problem remains in isolating
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which instruction contains the bug. Small programs illustrating a specific
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problem are a godsend.
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Legal Notices
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-------------
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The NetWinder Floating Point Emulator is free software. Everything Rebel.com
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has written is provided under the GNU GPL. See the file COPYING for copying
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conditions. Excluded from the above is the SoftFloat code. John Hauser's
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legal notice for SoftFloat is included below.
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-------------------------------------------------------------------------------
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SoftFloat Legal Notice
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SoftFloat was written by John R. Hauser. This work was made possible in
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part by the International Computer Science Institute, located at Suite 600,
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1947 Center Street, Berkeley, California 94704. Funding was partially
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provided by the National Science Foundation under grant MIP-9311980. The
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original version of this code was written as part of a project to build
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a fixed-point vector processor in collaboration with the University of
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California at Berkeley, overseen by Profs. Nelson Morgan and John Wawrzynek.
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THIS SOFTWARE IS DISTRIBUTED AS IS, FOR FREE. Although reasonable effort
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has been made to avoid it, THIS SOFTWARE MAY CONTAIN FAULTS THAT WILL AT
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TIMES RESULT IN INCORRECT BEHAVIOR. USE OF THIS SOFTWARE IS RESTRICTED TO
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PERSONS AND ORGANIZATIONS WHO CAN AND WILL TAKE FULL RESPONSIBILITY FOR ANY
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AND ALL LOSSES, COSTS, OR OTHER PROBLEMS ARISING FROM ITS USE.
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-------------------------------------------------------------------------------
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