> From: Mateja Marjanovic <mateja.marjano...@rt-rk.com> > Subject: [PATCH v2 2/2] target/mips: Make the results of MOD_<U|S>.<B|H|W|D> > the same as on hardware > > From: Mateja Marjanovic <mateja.marjano...@rt-rk.com> > > MSA instructions MOD_<U|S>.<B|H|W|D> when dividing by zero, > didn't return the same value when executed on a referent hardware > (FPGA MIPS 64 r6, little endian) and when executed on QEMU, which > is not a real bug, because the result when dividing by zero is > UNPREDICTABLE [1] (page 255, 256). > > [1] MIPS Architecture for Programmers > Volume IV-j: The MIPS64 SIMD > Architecture Module, Revision 1.12 > > Signed-off-by: Mateja Marjanovic <mateja.marjano...@rt-rk.com> > ---
Reviewed-by: Aleksandar Markovic <amarko...@wavecomp.com> > target/mips/msa_helper.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/target/mips/msa_helper.c b/target/mips/msa_helper.c > index 8c77f12..6693ba6 100644 > --- a/target/mips/msa_helper.c > +++ b/target/mips/msa_helper.c > @@ -657,14 +657,14 @@ static inline int64_t msa_mod_s_df(uint32_t df, int64_t > arg1, int64_t > arg2) > if (arg1 == DF_MIN_INT(df) && arg2 == -1) { > return 0; > } > - return arg2 ? arg1 % arg2 : 0; > + return arg2 ? arg1 % arg2 : arg1; > } > > static inline int64_t msa_mod_u_df(uint32_t df, int64_t arg1, int64_t arg2) > { > uint64_t u_arg1 = UNSIGNED(arg1, df); > uint64_t u_arg2 = UNSIGNED(arg2, df); > - return u_arg2 ? u_arg1 % u_arg2 : 0; > + return u_arg2 ? u_arg1 % u_arg2 : u_arg1; > } > > #define SIGNED_EVEN(a, df) \ > -- > 2.7.4