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Visitor raraz15
Registered: ‎05-14-2019

How to use a library?

Hello, I have to use Q Format Floating Point Arithtmetic in my project. I have limited knowledge on Libraries and packages  and I searched the internet for some time and asked my professors about it. No answers.

I found the Floating point package user’s guide of David Bishop and I try to do as in the description. So here is the question


I find the relevant files, but,

  1. I do not know what to do with these files? (Library Compiling, IEEE folder... so confused)
  2. I do not know how to use these libraries/packages in my VHDL code.


(I use Xilinx ISE 14.7 by the way)

Thanks a lot in advance :)



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2 Replies
Xilinx Employee
Xilinx Employee
Registered: ‎05-22-2018

Re: How to use a library?

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Visitor raraz15
Registered: ‎05-14-2019

Re: How to use a library?

I am trying to follow the instructions, but the guide doesn't specify anything about the Floating package, (I can try Fixed Point also as I don't want to fail this class )

Let's say I try the Fixed Package, the files that are mentionned in the vivado-logic-simulation.pdf are nowhere to be found, not on the computer, not on the internet, except David Bishop's  and his file names are different than in the vivado-logic-simulation.pdf. 

After being directed to https://www.xilinx.com/support/documentation/sw_manuals/xilinx2018_3/ug901-vivado-synthesis.pdf, page 214 it is said 

"First, compile the Fixed Package in the IEEE library. This package is available in the file: fixed_pkg_2008.vhd, in the scripts/rt/data/ directory in your Vivado install. This package is not precompiled in Vivado, so you must compile the file in your design.

• To compile the file using the GUI, copy the fixed_pkg_2008.vhd file from the Vivado build directory to your personal directory. Then in the Vivado IDE, add the fixed_pkg_2008.vhd file to your project, and make sure that it is compiled into the IEEE library.

• To compile the file using Tcl commands, type the following on the Tcl Console:

add_files –norecurse /fixed_pkg_2008.vhd

set_property library ieee [get_files /fixed_pkg_2008.vhd]

read_vhdl –vhdl2008 ./my_design.vhd

launch_runs synth_1 –jobs 4

wait_on_run synth_1

open_run synth_1 –name synth_1 

" I honestly do not know what to do at this point. Can anyone give me a working link for the library and descriptions for how to compile and use that library in Xilinx ISE 14.7?

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