1 Introduction 2 ============ 3 4 This directory contains the version 0.92 test release of the NetWinder 5 Floating Point Emulator. 6 7 The majority of the code was written by me, Scott Bambrough It is 8 written in C, with a small number of routines in inline assembler 9 where required. It was written quickly, with a goal of implementing a 10 working version of all the floating point instructions the compiler 11 emits as the first target. I have attempted to be as optimal as 12 possible, but there remains much room for improvement. 13 14 I have attempted to make the emulator as portable as possible. One of 15 the problems is with leading underscores on kernel symbols. Elf 16 kernels have no leading underscores, a.out compiled kernels do. I 17 have attempted to use the C_SYMBOL_NAME macro wherever this may be 18 important. 19 20 Another choice I made was in the file structure. I have attempted to 21 contain all operating system specific code in one module (fpmodule.*). 22 All the other files contain emulator specific code. This should allow 23 others to port the emulator to NetBSD for instance relatively easily. 24 25 The floating point operations are based on SoftFloat Release 2, by 26 John Hauser. SoftFloat is a software implementation of floating-point 27 that conforms to the IEC/IEEE Standard for Binary Floating-point 28 Arithmetic. As many as four formats are supported: single precision, 29 double precision, extended double precision, and quadruple precision. 30 All operations required by the standard are implemented, except for 31 conversions to and from decimal. We use only the single precision, 32 double precision and extended double precision formats. The port of 33 SoftFloat to the ARM was done by Phil Blundell, based on an earlier 34 port of SoftFloat version 1 by Neil Carson for NetBSD/arm32. 35 36 The file README.FPE contains a description of what has been implemented 37 so far in the emulator. The file TODO contains a information on what 38 remains to be done, and other ideas for the emulator. 39 40 Bug reports, comments, suggestions should be directed to me at 41 <scottb@netwinder.org>. General reports of "this program doesn't 42 work correctly when your emulator is installed" are useful for 43 determining that bugs still exist; but are virtually useless when 44 attempting to isolate the problem. Please report them, but don't 45 expect quick action. Bugs still exist. The problem remains in isolating 46 which instruction contains the bug. Small programs illustrating a specific 47 problem are a godsend. 48 49 Legal Notices 50 ------------- 51 52 The NetWinder Floating Point Emulator is free software. Everything Rebel.com 53 has written is provided under the GNU GPL. See the file COPYING for copying 54 conditions. Excluded from the above is the SoftFloat code. John Hauser's 55 legal notice for SoftFloat is included below. 56 57 ------------------------------------------------------------------------------- 58 59 SoftFloat Legal Notice 60 61 SoftFloat was written by John R. Hauser. This work was made possible in 62 part by the International Computer Science Institute, located at Suite 600, 63 1947 Center Street, Berkeley, California 94704. Funding was partially 64 provided by the National Science Foundation under grant MIP-9311980. The 65 original version of this code was written as part of a project to build 66 a fixed-point vector processor in collaboration with the University of 67 California at Berkeley, overseen by Profs. Nelson Morgan and John Wawrzynek. 68 69 THIS SOFTWARE IS DISTRIBUTED AS IS, FOR FREE. Although reasonable effort 70 has been made to avoid it, THIS SOFTWARE MAY CONTAIN FAULTS THAT WILL AT 71 TIMES RESULT IN INCORRECT BEHAVIOR. USE OF THIS SOFTWARE IS RESTRICTED TO 72 PERSONS AND ORGANIZATIONS WHO CAN AND WILL TAKE FULL RESPONSIBILITY FOR ANY 73 AND ALL LOSSES, COSTS, OR OTHER PROBLEMS ARISING FROM ITS USE. 74 -------------------------------------------------------------------------------
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