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