Provide more details on compilers

source/compilers.md

@@ -12,12 +12,18 @@ sd_hide_title: true
 <h4> <b> GNU Fortran Compiler</b></h4>
 
 [GNU Fortran Compiler (gfortran)](https://gcc.gnu.org/fortran/) is a mature
-free and open source compiler, part of the GNU Compiler Collection.
+compiler, part of the GNU Compiler Collection.
+
+*Free and open source under
+[GNU General Public License](https://gcc.gnu.org/onlinedocs/gcc-4.2.4/gfortran/Copying.html#Copying).*
 
 [OpenCoarrays](http://www.opencoarrays.org/) is a library and compiler wrapper
 around gfortran which enables the parallel programming features of Fortran 2018
 with gfortran.
 
+*Free and open source under
+[BSD-3 license](https://github.com/sourceryinstitute/OpenCoarrays/blob/main/LICENSE).*
+
 <h4> <b> LLVM Flang</b></h4>
 
 [Flang](https://github.com/llvm/llvm-project/tree/main/flang)
@@ -26,16 +32,26 @@ added to LLVM.
 It is implemented in modern C++ and uses a Fortran-oriented MLIR dialect for lowering to LLVM IR.
 This project is under active development.
 
+*Free and open source under
+[Apache License v2.0 with LLVM Exceptions](https://github.com/llvm/llvm-project/blob/main/flang/LICENSE.TXT).*
+
 <h4> <b> Current Flang</b></h4>
 
-[Flang](https://github.com/flang-compiler/flang) is an open source compiler
-based on the NVIDIA/PGI commercial compiler.
+[Flang](https://github.com/flang-compiler/flang) is a compiler based on the
+NVIDIA/PGI commercial compiler.
+
+*Free and open source under
+[Apache License v2.0 with LLVM Exceptions](https://github.com/flang-compiler/flang/blob/master/LICENSE.txt).*
 
 <h4> <b> LFortran </b></h4>
 
 [LFortran](https://lfortran.org) is a modern, interactive, LLVM-based Fortran
 compiler.
 Also available online at [dev.lfortran.org](https://dev.lfortran.org/) using a statically served, WASM based LFortran Compiler for running code in web browsers.
+
+*Free and open source under
+[BSD-3 license](https://github.com/lfortran/lfortran/blob/main/LICENSE).*
+
 <p style="font-size:24px;color:#734f96;"><b>Commercial compilers</b></p>
 
 <h4> <b> Intel oneAPI</b></h4>
@@ -51,14 +67,19 @@ Python. Intel oneAPI HPC Toolkit provides
 - Intel Fortran Compiler Classic (`ifort`), a mature compiler
   with full Fortran 2018 support, for CPUs only.
 
-The current version of Intel oneAPI is available for free, and support can be purchased.
 Currently the ifx compiler supports Linux and Windows platforms for x86-64 architectures. ifort supports Linux, Windows, and macOS.
+
+*The current version of Intel oneAPI is
+[available for free](https://www.intel.com/content/www/us/en/developer/articles/tool/oneapi-standalone-components.html),
+and support can be purchased.
 Community support is available for the free version at the [Intel Developer forum](https://community.intel.com/t5/Intel-Fortran-Compiler/bd-p/fortran-compiler).
 Optionally, you can purchase [Priority Support](https://www.intel.com/content/www/us/en/developer/get-help/priority-support.html) with additional benefits including access to previous versions of ifort and ifx.
+For licensing information related to Intel oneAPI, see the
+[Intel End-User License Agreement](https://www.intel.com/content/www/us/en/developer/articles/license/end-user-license-agreement.html)*.
 
 <h4> <b> NAG </b></h4>
 
-The latest [NAG Fortran Compiler](https://www.nag.com/nag-compiler)
+The latest [NAG Fortran Compiler](https://nag.com/nag-compiler)
 release (7.0) has extensive support for legacy and modern Fortran features including parallel programming with coarrays, as well as additional support for programming with OpenMP.
 
 The Compiler also provides significant support for Fortran 2018 (atomic
@@ -68,14 +89,19 @@ platforms include supporting tools for software development: source file
 polishers, dependency generator for module and include files, call-graph
 generator, interface builder and a precision unifier.
 
+*Purchasable from the [NAG website](https://nag.com/buy-now/) under the
+[NAG software license](https://support.nag.com/termsandconditions/nag-software-licence-t-and-c.pdf)*
+
 <h4> <b> NVIDIA</b></h4>
 
 The [NVIDIA HPC SDK](https://developer.nvidia.com/hpc-sdk) C, C++, and Fortran compilers, former [PGI compilers](https://www.pgroup.com/products/index.htm), support GPU acceleration of HPC modeling and simulation applications with standard C++ and Fortran, OpenACC® directives, and CUDA®. GPU-accelerated math libraries maximize performance on common HPC algorithms, and optimized communications libraries enable standards-based multi-GPU and scalable systems programming.
 
-NVHPC compilers are available free of charge.
 Currently the compiler supports Linux platforms and x86_64, ppc64le and aarch64 architectures.
 Community support is available at the [HPC compiler forum](https://forums.developer.nvidia.com/c/accelerated-computing/hpc-compilers/nvc-nvc-and-nvfortran/313).
 
+*[Freely available](https://developer.nvidia.com/hpc-sdk-downloads) under
+[NVIDIA Software License Agreement](https://docs.nvidia.com/hpc-sdk/eula/index.html).*
+
 <h4> <b> HPE / Cray</b></h4>
 
 The [Cray Compiling Environment (CCE)](https://developer.hpe.com/platform/hpe-cray-programming-environment/home/)
@@ -86,6 +112,10 @@ highly multithreaded. It includes optimizing compilers that automatically
 exploit the scalar, vector and multithreading hardware capabilities of the Cray
 system. CCE supports Fortran, C and C++.
 
+*Purchasable from
+[HPC Support Center](https://support.hpe.com/connect/s/product) under HPE
+License Terms.*
+
 <h4> <b> IBM </b></h4>
 
 [IBM® XL Fortran](https://www.ibm.com/us-en/marketplace/xl-fortran-linux-compiler-power)
@@ -96,9 +126,15 @@ your hardware utilization. IBM XL Fortran for Linux optimizes your
 infrastructure on IBM Power Systems™ in support of extensive numerical,
 scientific and high-performance computing.
 
-A community edition of the IBM XL compilers are available free of charge.
 The compilers support Linux and AIX platforms and ppc64le architectures.
 
+*Purchasable from the
+[IBM website](https://www.ibm.com/products/fortran-compiler-family) under the
+relevant
+[IBM License Agreement](https://www.ibm.com/about/software-licensing/us-en). A
+[community edition](https://www.ibm.com/products/open-xl-fortran-linux-compiler-power)
+of the IBM XL compilers are available free of charge.*
+
 <h4> <b> AMD </b></h4>
 
 The [AMD Optimizing C/C++ Compiler (AOCC)](https://developer.amd.com/amd-aocc/)
@@ -115,22 +151,35 @@ applications.
 
 The AOCC compilers are available free of charge and support Linux platforms with x86_64 architectures.
 
+*Freely available on the
+[AMD website](https://www.amd.com/en/developer/aocc.html) under the
+[AMD AOCC End-User License Agreement](https://www.amd.com/en/developer/aocc/aocc-compiler/eula.html).*
+
 <h4> <b> ARM </b></h4>
 
-[Linux user-space Fortran compiler](https://developer.arm.com/tools-and-software/server-and-hpc/compile/arm-compiler-for-linux/arm-fortran-compiler).
+[Arm Fortran compiler for Linux](https://developer.arm.com/Tools%20and%20Software/Arm%20Fortran%20Compiler).
 Tailored for HPC and scientific codes, with support for popular Fortran and
 OpenMP standards and tuned for leading server-class Arm-based platforms. Built
 on the open source Flang front-end, and the LLVM‑based optimization and code
 generation back-end. Available as part of the Arm Compiler for Linux package.
 
+*Freely available on the
+[Arm website](https://developer.arm.com/documentation/102621/0100/Download?lang=en) under the
+[License agreement](https://developer.arm.com/documentation/102621/0100).*
+
 <h4> <b> Oracle / Sun </b></h4>
 
 [Oracle C, C++, Fortran Compiler](https://www.oracle.com/application-development/technologies/developerstudio-features.html)
-is highly optimized for Oracle systems, on-premise and in the cloud
+is highly optimized for Oracle systems, on-premise and in the cloud.
+
+- Advanced code generation technology for the latest Oracle SPARC and x86 based systems.
+- Support for the latest industry standards, including C++14, C++11, C11 and OpenMP 4.0 and extensive GCC compatibility features.
+- Automatic code analysis during compilation and automatic stack overflow protection at application runtime.
 
-- Advanced code generation technology for the latest Oracle SPARC and x86 based systems
-- Support for the latest industry standards, including C++14, C++11, C11 and OpenMP 4.0 and extensive GCC compatibility features
-- Automatic code analysis during compilation and automatic stack overflow protection at application runtime
+*Purchasable from the
+[Oracle website](https://www.oracle.com/application-development/technologies/developerstudio.html)
+under the
+[Oracle License and Services Agreement](https://www.oracle.com/us/corporate/pricing/olsa-ire-v122304-070683.pdf).*
 
 <h4> <b> Silverfrost FTN95 </b></h4>
 
@@ -141,21 +190,34 @@ range of supporting software. All standard and many vendor-specific legacy
 language features are supported, so that Fortran projects may be any combination
 of Fortran 77, Fortran 90 and Fortran 95.
 Some features of Fortran 2003 and 2008 have been [added](https://www.silverfrost.com/19/ftn95/support/ftn95_revision_history.aspx).
-Silverfrost Fortran runs on Windows / x86_64. There is a free personal edition.
+Silverfrost Fortran runs on Windows / x86_64.
+
+*Purchasable from the
+[Silverfrost website](https://www.silverfrost.com/P1001/shop/silverfrost_ftn95.aspx)
+(there is also a
+[free personal edition](https://www.silverfrost.com/32/ftn95/ftn95_personal_edition.aspx)
+under the
+[Silverfrost Fortran FTN95 License Agreement](https://www.silverfrost.com/44/ftn95/ftn95_licence_options.aspx)*.
 
 <h4> <b> NEC </b></h4>
 
 [The Fortran compiler](https://www.nec.com/en/global/solutions/hpc/sx/tools.html)
 conforms to the Fortran-2003 standard (ISO/IEC 1539-1:2004) and supports many
 features from Fortran-2008 (ISO/IEC 1539-1:2010).
 
+*Freely available from the
+[community repository](https://sxauroratsubasa.sakura.ne.jp/repos/community/sdk/)
+(see [blog post](https://sx-aurora.github.io/posts/nec-compilers-no-license/)
+for more information) under the
+[SX-Aurora TSUBASA Free Software License](https://sxauroratsubasa.sakura.ne.jp/documents/support/pdfs/AuroraSW_Free_List.pdf).*
+
 <h4> <b> LCC </b></h4>
 
 [MCST C, C++, Fortran Compiler](http://mcst.ru/lcc) with full support of Fortran-95
 (ISO/IEC 1539:1997) and partial support of Fortran-2003 (ISO/IEC 1539:2004),
 Fortran-2008 (ISO/IEC 1539:2010) and Fortran-2018 (ISO/IEC 1539:2018). Used for
-russian processor architectures Elbrus (e2k) and SPARC (MCST-R), also a cross-compiler
-for x86_64 architecture is available.
+Russian processor architectures Elbrus (e2k) and SPARC (MCST-R), also a
+cross-compiler for x86_64 architecture is available.
 
 <h3> Discontinued </h3>