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OpenFPU64
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============================
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Peter Hüwe
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V.0.1, Januar 2009, License: CC-by-sa
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:author initials: PH
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:email: peterhuewe@gmx.d
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:license: CC-by-sa
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About OpenFPU64
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---------------
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OpenFPU64 is a free and open source implementation of a double precision floating point unit.
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The openFPU64 currently features:
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* double precision
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* Addition/Subtraction
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* Multiplication
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* rounding (to nearest even)
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* subnormals/denormals
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* validated against IEEE754 using TestFloat (http://www.jhauser.us/arithmetic/TestFloat.html)
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* Compatible with Avalon Bus
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* Wishbone interface will be provided soon
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The openFPU is tested with a Cyclone II and a CycloneIII fpga.
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Usage in QuartusII SOPC (tm)
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----------------------------
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In order to use openFPU64 copy all VHDL files (*.vhd) and the TCL file (openfpu64_hw.tcl) to the root directory of your QuartusII Project.
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(alternative: 'make quartus_distribution' and copy everything in openfpu64_quartus/ to the root directory of your Quartus II project)
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Then open the QuartusII and from Quartus launch the SOPC Builder.
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In SOPC Builder click new component in the left pane and select
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File -> open and open the openfpu64_hw.tcl file.
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By clicking on finish, the openFPU64 is added to your library.
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Now add openFPU64 to your SOPC-design by double clicking on it, click Generate as usual.
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In some rare cases your have to assign new Base and End Adresses,
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clicking "System->Auto-Assign Base Adresses" does resolve this.
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Now click Generate as usual, close SOPC Builder afterwards and compile your design as usual using Quartus.
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Driver/Libary in NiosII:
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------------------------
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add the openfpu64.c and openfpu64.h files (in nios-driver)to your NiosII Project.
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To use this library/driver, add the fpu.[ch] files to your application
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and add these linker flags.
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Click right on your application, choose properties, C/C++ Build
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-> Linker -> General and type
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"-Wl,--wrap,__adddf3,--wrap,__subdf3,--wrap,__muldf3"
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For each implemented function, add another --wrap,__functioname
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Development:
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------------
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If you'd like to do some development on openFPU64, you can use the Makefile together with GHDL (http://ghdl.free.fr/)
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You can create several different testbenches by issuing one of these commands:
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* empty_testsuite
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* addsub_testsuite
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* custom_testsuite
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* add_testsuite
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* sub_testsuite
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* mul_testsuite
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The custom_testsuite contains several hand crafted testsuites for ADD/SUB/MUL, the others are quite big (45k,95k testcases) and generated using TestFloat.
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The testbench is made up of openfpu64_tb.head.vhd, openfpu64_tb.tail.vhd and the testscases in tests/.
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If you want to change the testbench structure please DO NOT change openfpu64_tb.vhd but rather openfpu64_tb.head.vhd, otherwise your changes will be overwritten by make *_testsuite.
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The empty testsuite is for 'resetting' the openfpu64_tb to be committed to svn.
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Please use make empty_testsuite before checking your sources in.
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Note:
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-----
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QuartusII, Nios, Cyclone, QuartusII SOPC Builders are registered Trademarks of Altera Corporation, 101 Innovation Drive, San Jose, California 95134, USA. All rights reserved.
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Meanwhile, for questions contact me at peterhuewe@gmx.de and I'm glad to help you out
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