libmad-0.15.1b fails to compile on cfarm230

Hi!
   I'm finding libmad's compilation fails on cfarm230.cfarm.net, an
     EdgeRouter4 (big-endian)
     mips64
     Cavium Octeon III V0.2 FPU V0.0
     Debian 10.13 buster 4.9.79-UBNT_E300
with
     gcc (Debian 8.3.0-6) 8.3.0
saying
     In file included from layer12.c:34:
     layer12.c: In function 'I_sample':
     fixed.h:307:5: error: impossible constraint in 'asm'
          asm ("mult %2,%3"  \
          ^~~
     fixed.h:455:8: note: in expansion of macro 'MAD_F_MLX'
             MAD_F_MLX(__hi, __lo, (x), (y));  \
             ^~~~~~~~~
     layer12.c:94:10: note: in expansion of macro 'mad_f_mul'
        return mad_f_mul(sample, linear_table[nb - 2]);
               ^~~~~~~~~
     make[2]: *** [Makefile:383: layer12.lo] Error 1

If I configure with --disable-osa instead I get the same error and it needs
    ./configure --enable-fpm=default
to work.

Am I missing something, or is that what it should do?

     M