M_fmul_subtract
extern int M_fmul_subtract(UCHAR *, UCHAR *, UCHAR *, int);
stmp = M_fmul_subtract(fmul_a9, fmul_a1, fmul_a0, mii);
stmp *= M_fmul_subtract(fmul_b9, fmul_b0, fmul_b1, mii);
M_fmul_subtract(fmul_a9, rr, fmul_b9, (2 * sz));