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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 | ------------------------------------------------------------------------------- |