MIPS-specific porting issue

Dear MIPS porters,

I am debugging ocaml-mirage-crypto build on mipsel.

It uses the following code:

> #if defined (__i386__) || defined (__x86_64__)
>   return Val_long (__rdtsc ());
> #elif defined (__arm__) || defined (__aarch64__)
>   return Val_long (read_virtual_count ());
> #elif defined(__powerpc64__)
>   return Val_long (read_cycle_counter ());
> #elif defined(__riscv) && (64 == __riscv_xlen)
>   return Val_long (rdcycle64 ());
> #elif defined (__s390x__)
>   return Val_long (getticks ());
> #else
> #error ("No known cycle-counting instruction.")
> #endif

I have trouble finding a suitable implementation for this on mipsel.
Would you have a hint?


Cheers,