Are CBLAS functions linked with fortran code or the optimised kernels under kernel/?

[jli05]

For example, lapack-netlib/CBLAS/src/cblas_sgemv.c refers to F77_sgemv. So are the CBLAS functions linked with fortran code eventually? Where is the fortran code they are linked with?

Can the CBLAS functions be linked with the optimised kernels under kernel/, eg kernel/arm64/gemv_n_sve.c, kernel/riscv64/gemv_n_rvv.c?

@martin-frbg @brada4

[brada4]

Your assumptions are misinformed.
cblas and BLAS entrypoints are emitted from same source files and reference glue you are looking at is never applied.
Please dont tag me again.

[jli05]

Sorry I'm just a new person.

To confirm, as you said the CBLAS entry points are emitted from the same source files, does that mean lapack-netlib/CBLAS/src/* are not used to generate the CBLAS lib?

[brada4]

Compile it once maybe?

[martin-frbg]

The lapack-netlib subtree is a full copy of the Reference-LAPACK implementation from https://github.com/Reference-LAPACK/lapack (also sometimes called "netlib" LAPACK) but the BLAS and CBLAS parts of it are never built. Instead, the files under "interface" get compiled twice, once with "CBLAS" defined to generate the CBLAS interface, and once without it to generate the BLAS one. The interfaces either call the respective machine-specific BLAS kernels directly (typical for level 1 BLAS functions) or through the corresponding lecel2/level3 driver code that manages splitting the workload into cache-sized tiles (Goto's block matrix algorithm)

[brada4]

Take simple function and compare fortran and c calling conventions, double/single float/complex fortran/c exports are compiled from same C source.

https://github.com/OpenMathLib/OpenBLAS/blob/develop/interface/dot.c

[jli05]

Thanks @martin-frbg @brada4 Your both's should qualify as answers.