What about contradictions?

[ghost]

The readme.md files claims that the license of the source code is Creative Commons by SA (CC BY-SA 4.0 as found on third party web-site). According to this statement this software is distributed in it's source code and it is legit to freely use this source code for any purpose.
But in the same time this project uses cores for actual hardware, which depend on proprietary software to build them:

• software from Xilinx. Found software is a part of Xilinx's suits for developers, which are not freely available. See Xilinx Product Licensing for more details. I guess the use of these tools implies a special fee-based license to use it (and even for a derived hardware). Also I found a tool here Data2MEM O.61xd which is from Xilinx Vivado Suit Release 13.2.
• TASM Assembler version 3.2 (file tasm64.exe), Copyright (C) 2001 Squak Valley Software which is "shareware" and needs a registration to use it. See here for details on distribution.

This raises such questions as:

• is it possible to use free software (or at least open-source software) to build cores for ZX-Uno for now?
• if not, where's the description of how to build cores for ZX-Uno? For some reason there's no description of the build process and it's dependencies nor here, nor in ZX-Uno's manuals.

What about a legal solution to solve this contradictions? For example - to use open-source developing tools from OSFPGA Foundation?

[antoniovillena]

I don't know a way to compile with different tools than proprietary xilinx ones. About tasm tell me where is and if source file is short I can adapt to NASM or similar

[nihirash]

There aren't free/open tools for Spartan 6.

For Spartan 7 there is a simple tools but as I understand they aren't ready for building ZX-Uno sources.
If we talk about FLOSS tools for HDL synthesis only Lattice have good support(iCE40 and ECP5) with Yosys+NextPNR+Project Trellis/Project Icestorm.