XBLAS Fortran->C interface

Describes the XBLAS changes that add a Fortran interface.

Table of Contents

• 1 Introduction
• 2 Relevant patches to the XBLAS
• 3 Current XBLAS snapshot

1 Introduction

We need a portable-enough method for Fortran LAPACK routines to call the C XBLAS routines. By adding a few ugly hacks to the XBLAS M4 generators, we can allow for the common Fortran name-mangling possibilities.

The new src/f2c-bridge.h defines FC_FUNC and FC_FUNC_ macros similar to autoconf's. Rather than rely on build-time tests, we ask the users to pass the correct cpp options from the following in their make.inc:

• CONFIG_FC_UNDERSCORE

  Add one underscore to each name.

• CONFIG_FC_DBL_UNDERSCORE

  If the name has an underscore in it already, add two; otherwise add one

• CONFIG_FC_UCASE

  The name is converted to upper-case; default is lower-case.

• CONFIG_FC_RETURNS_DBL_REAL

  REAL values are returned in C doubles as in f2c. (Currently unused, but will be needed to call SLAMCH from C.)

2 Relevant patches to the XBLAS

These are just to show individual, localized changes and their explanations.

• 0001-New-files-for-the-Fortran-C-bridge.txt

  Adds the f2c-bridge.h header, the changes to the common M4 file, and an interface for BLAS_fpinfo_x.

• 0002-Add-the-Fortran-C-bridge-to-the-build-system.txt

  Includes CFLAGS in make.* according to my best guesses, and builds the new *-f2c.c files.

• 0003-Document-the-installation-and-Fortran-C-bridge-in-the-README.txt

  A little bit of documentation pointing at src/f2c-bridge.h for the options that need selected. More documentation has been added to src/f2c-bridge.h since the first patch above.

• 0004-The-F77-bindings-should-have-no-order-parameter.txt

  Fixes a mistake in the first patch; the F77 bindings don't allow for row-major ordering.

3 Current XBLAS snapshot

A snapshot of my current tree is in xblas-2006.09.09.tar.bz2. This isn't an "official" tree yet; ask Yozo for a real one.

I'm not sure how UTK wants to handle including XBLAS changes, and I'm also not 100% sure which version currently is in the LAPACK repo.

I think this snapshot has the following additional changes:

• Jason Riedy:
  • New files for the Fortran->C bridge.
  • Add the Fortran->C bridge to the build system.
  • Document the installation and Fortran->C bridge in the README.
  • The F77 bindings should have no order parameter.
• Xiaoye S. Li:
  • Handle the case n_fix = 0, n_mix = 2, n = 2 in complex testgen.
• Yozo Hida:
  • Added README.devel describing generating C files from m4 files.
  • Fix tab vs space alignment problem in Makefile.m4.
  • Standardize testing/*/Makefile a bit.
  • Added .gitignore to ignore generated files.
  • Removed circular dependency of symv-test-lib.
  • Make m4/Makefile depend on m4/cblas.m4.
  • Make src/Makefile depend on m4/cblas.m4.
  • Fix memory leak in BLAS_symm_testgen.
  • Removed non-autogenrated m4/test-*/Makefile from gitignore.
  • Auto-generate m4/test-gemv2/Makefile.
  • Added separate header target in top-level Makefile.
  • s/ARCH/AR/g; s/ARCHFLAGS/AR_FLAGS/g;
  • Make dot target in top-level Makefile to build and test dot.
  • Added m4/test-gemv2/Makefile to .gitignore.
  • Use shell AND operator && to change directory and run recursive make.
  • Auto-generate m4/test-gemv/Makefile.
  • Merge branch 'master' into f2c-bridge
  • Avoid circular dependency in top-level Makefile.
  • Merge branch 'master' into f2c-bridge

Author: E. Jason Riedy <ejr@cs.berkeley.edu>

Date: 2006/09/09 04:45:29 PM