Rockbox

@rockbox/apps/codecs/libmad/fixed.h,line 299
# define MAD_F_MLX(hi, lo, x, y) \

  asm ("mult  %2,%3"  \
       : "=l" (lo), "=h" (hi)  \
       : "%r" (x), "r" (y))

Since gcc 4.4 the MIPS port no longer recognizes the “h” asm constraint.
It was necessary to remove this constraint in order to avoid generating unpredictable code sequences.We can achieve the same effect using 128-bit types:
typedef unsigned int u64_di_t attribute 1));
# define MAD_F_MLX(hi, lo, x, y) \
do { \

 u64_di_t __ll = (u64_di_t) (x) * (y); \
 hi = __ll >> 32; \
 lo = __ll; \

}while(0)

See also:GCC 4.4 release note
http://gcc.gnu.org/gcc-4.4/

This patch is a possible workaround that works on both old and new version of gcc.