[dragontamer]

BLAS itself has been rewritten in Nvidia CUDA and AMD HIP, and is likely the workhorse in this case. (Remember that Frontier is mostly GPUs and the bulk of code should be GPU compatible)

Presumably that old Fortran code has survived many generations of ports: Connection Machine, DEC Alpha, Intel Itanium, SPARC and finally today's GPU heavy systems. The BLAS layer keeps getting rewritten but otherwise the bulk of the simulators still works.