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1 This directory contains the version 0.92 test release of the NetWinder 2 Floating Point Emulator. 3 4 The majority of the code was written by me, Scott Bambrough It is 5 written in C, with a small number of routines in inline assembler 6 where required. It was written quickly, with a goal of implementing a 7 working version of all the floating point instructions the compiler 8 emits as the first target. I have attempted to be as optimal as 9 possible, but there remains much room for improvement. 10 11 I have attempted to make the emulator as portable as possible. One of 12 the problems is with leading underscores on kernel symbols. Elf 13 kernels have no leading underscores, a.out compiled kernels do. I 14 have attempted to use the C_SYMBOL_NAME macro wherever this may be 15 important. 16 17 Another choice I made was in the file structure. I have attempted to 18 contain all operating system specific code in one module (fpmodule.*). 19 All the other files contain emulator specific code. This should allow 20 others to port the emulator to NetBSD for instance relatively easily. 21 22 The floating point operations are based on SoftFloat Release 2, by 23 John Hauser. SoftFloat is a software implementation of floating-point 24 that conforms to the IEC/IEEE Standard for Binary Floating-point 25 Arithmetic. As many as four formats are supported: single precision, 26 double precision, extended double precision, and quadruple precision. 27 All operations required by the standard are implemented, except for 28 conversions to and from decimal. We use only the single precision, 29 double precision and extended double precision formats. The port of 30 SoftFloat to the ARM was done by Phil Blundell, based on an earlier 31 port of SoftFloat version 1 by Neil Carson for NetBSD/arm32. 32 33 The file README.FPE contains a description of what has been implemented 34 so far in the emulator. The file TODO contains a information on what 35 remains to be done, and other ideas for the emulator. 36 37 Bug reports, comments, suggestions should be directed to me at 38 <scottb@netwinder.org>. General reports of "this program doesn't 39 work correctly when your emulator is installed" are useful for 40 determining that bugs still exist; but are virtually useless when 41 attempting to isolate the problem. Please report them, but don't 42 expect quick action. Bugs still exist. The problem remains in isolating 43 which instruction contains the bug. Small programs illustrating a specific 44 problem are a godsend. 45 46 Legal Notices 47 ------------- 48 49 The NetWinder Floating Point Emulator is free software. Everything Rebel.com 50 has written is provided under the GNU GPL. See the file COPYING for copying 51 conditions. Excluded from the above is the SoftFloat code. John Hauser's 52 legal notice for SoftFloat is included below. 53 54 ------------------------------------------------------------------------------- 55 SoftFloat Legal Notice 56 57 SoftFloat was written by John R. Hauser. This work was made possible in 58 part by the International Computer Science Institute, located at Suite 600, 59 1947 Center Street, Berkeley, California 94704. Funding was partially 60 provided by the National Science Foundation under grant MIP-9311980. The 61 original version of this code was written as part of a project to build 62 a fixed-point vector processor in collaboration with the University of 63 California at Berkeley, overseen by Profs. Nelson Morgan and John Wawrzynek. 64 65 THIS SOFTWARE IS DISTRIBUTED AS IS, FOR FREE. Although reasonable effort 66 has been made to avoid it, THIS SOFTWARE MAY CONTAIN FAULTS THAT WILL AT 67 TIMES RESULT IN INCORRECT BEHAVIOR. USE OF THIS SOFTWARE IS RESTRICTED TO 68 PERSONS AND ORGANIZATIONS WHO CAN AND WILL TAKE FULL RESPONSIBILITY FOR ANY 69 AND ALL LOSSES, COSTS, OR OTHER PROBLEMS ARISING FROM ITS USE. 70 -------------------------------------------------------------------------------