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[/] [openrisc/] [trunk/] [or1ksim/] [softfloat/] [README] - Blame information for rev 855

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1 233 julius
                                SoftFloat
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This provides a software implementation of functions performing floating point
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operations according to the IEEE 754 standard.
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It is used in or1ksim due to problems arising when using the simulator host
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machine's floating point unit to perform single precision floating point
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calculations (or even double, in some cases.) Typically the host machine's FPU
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will support extended (80-bit), or higher, precision, resulting in values which
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can differ from those which are calculated on a true single or double precision
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floating point unit (very small differences when in rounding and generating
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status flags.)
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Although using a software implementation is slow, it ensures an accurate
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simulation of a single or double precision floating point unit.
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This software was sourced from the author's (John Hauser) site:
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http://www.jhauser.us/arithmetic/SoftFloat.html
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21 236 jeremybenn
Note that the code cannot be compiled with -O0 for debugging purpose, because
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of the approach used to code inlining. Additional macros have been added to
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ease this problem. For debugging purposes, Or1ksim should be configured adding
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CFLAGS="-O0 -DINLINE=static -DNO_SOFTFLOAT_UNUSED" to the configure line.
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26 233 julius
Julius Baxter, August 1, 2010
27 236 jeremybenn
Jeremy Bennett, August 4, 2010 (-O0 compilation)

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