| 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. |
| ------------------------------------------------------------------------------- |
