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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
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tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /Documentation/arm/nwfpe/README
downloadconfigs-2.6.12-rc2.tar.gz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
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+This directory contains the version 0.92 test release of the NetWinder
+Floating Point Emulator.
+
+The majority of the code was written by me, Scott Bambrough It is
+written in C, with a small number of routines in inline assembler
+where required. It was written quickly, with a goal of implementing a
+working version of all the floating point instructions the compiler
+emits as the first target. I have attempted to be as optimal as
+possible, but there remains much room for improvement.
+
+I have attempted to make the emulator as portable as possible. One of
+the problems is with leading underscores on kernel symbols. Elf
+kernels have no leading underscores, a.out compiled kernels do. I
+have attempted to use the C_SYMBOL_NAME macro wherever this may be
+important.
+
+Another choice I made was in the file structure. I have attempted to
+contain all operating system specific code in one module (fpmodule.*).
+All the other files contain emulator specific code. This should allow
+others to port the emulator to NetBSD for instance relatively easily.
+
+The floating point operations are based on SoftFloat Release 2, by
+John Hauser. SoftFloat is a software implementation of floating-point
+that conforms to the IEC/IEEE Standard for Binary Floating-point
+Arithmetic. As many as four formats are supported: single precision,
+double precision, extended double precision, and quadruple precision.
+All operations required by the standard are implemented, except for
+conversions to and from decimal. We use only the single precision,
+double precision and extended double precision formats. The port of
+SoftFloat to the ARM was done by Phil Blundell, based on an earlier
+port of SoftFloat version 1 by Neil Carson for NetBSD/arm32.
+
+The file README.FPE contains a description of what has been implemented
+so far in the emulator. The file TODO contains a information on what
+remains to be done, and other ideas for the emulator.
+
+Bug reports, comments, suggestions should be directed to me at
+<scottb@netwinder.org>. General reports of "this program doesn't
+work correctly when your emulator is installed" are useful for
+determining that bugs still exist; but are virtually useless when
+attempting to isolate the problem. Please report them, but don't
+expect quick action. Bugs still exist. The problem remains in isolating
+which instruction contains the bug. Small programs illustrating a specific
+problem are a godsend.
+
+Legal Notices
+-------------
+
+The NetWinder Floating Point Emulator is free software. Everything Rebel.com
+has written is provided under the GNU GPL. See the file COPYING for copying
+conditions. Excluded from the above is the SoftFloat code. John Hauser's
+legal notice for SoftFloat is included below.
+
+-------------------------------------------------------------------------------
+SoftFloat Legal Notice
+
+SoftFloat was written by John R. Hauser. This work was made possible in
+part by the International Computer Science Institute, located at Suite 600,
+1947 Center Street, Berkeley, California 94704. Funding was partially
+provided by the National Science Foundation under grant MIP-9311980. The
+original version of this code was written as part of a project to build
+a fixed-point vector processor in collaboration with the University of
+California at Berkeley, overseen by Profs. Nelson Morgan and John Wawrzynek.
+
+THIS SOFTWARE IS DISTRIBUTED AS IS, FOR FREE. Although reasonable effort
+has been made to avoid it, THIS SOFTWARE MAY CONTAIN FAULTS THAT WILL AT
+TIMES RESULT IN INCORRECT BEHAVIOR. USE OF THIS SOFTWARE IS RESTRICTED TO
+PERSONS AND ORGANIZATIONS WHO CAN AND WILL TAKE FULL RESPONSIBILITY FOR ANY
+AND ALL LOSSES, COSTS, OR OTHER PROBLEMS ARISING FROM ITS USE.
+-------------------------------------------------------------------------------