Re: [Qemu-devel] [PULL v4 29/46] target/mips: Add emulation of DSP ASE for nanoMIPS - part 1

[Stefan Markovic <smarkovic@wavecomp.com>]

On 16.10.18. 16:00, Peter Maydell wrote:
> On 23 August 2018 at 14:34, Aleksandar Markovic
> <aleksandar.markovic@rt-rk.com> wrote:
>> From: Stefan Markovic <smarkovic@wavecomp.com>
>>
>> Add emulation of DSP ASE instructions for nanoMIPS - part 1.
>>
>> Reviewed-by: Aleksandar Markovic <amarkovic@wavecomp.com>
>> Signed-off-by: Aleksandar Markovic <amarkovic@wavecomp.com>
>> Signed-off-by: Stefan Markovic <smarkovic@wavecomp.com>
> Hi. Coverity points out a bug in this patch (CID 1395627):
>
>> ---
>>   target/mips/translate.c | 554 ++++++++++++++++++++++++++++++++++++++++++++++++
>>   1 file changed, 554 insertions(+)
>>
>> diff --git a/target/mips/translate.c b/target/mips/translate.c
>> index 95632dd..d3635e7 100644
>> --- a/target/mips/translate.c
>> +++ b/target/mips/translate.c
>> @@ -18061,6 +18061,554 @@ static void gen_pool32f_nanomips_insn(DisasContext *ctx)
>>       }
>>   }
>>
>> +static void gen_pool32a5_nanomips_insn(DisasContext *ctx, int opc,
>> +                                       int rd, int rs, int rt)
>> +{
> [...]
>
>> +    case NM_SHRA_R_PH:
>> +        check_dsp(ctx);
>> +        tcg_gen_movi_tl(t0, rd >> 1);
>> +        switch (extract32(ctx->opcode, 10, 1)) {
>> +        case 0:
>> +            /* SHRA_PH */
>> +            gen_helper_shra_ph(v1_t, t0, v1_t);
>> +            break;
>> +            gen_store_gpr(v1_t, rt);
> This gen_store_gpr() call is unreachable because it
> is after the 'break'. Should the two lines be in the
> other order?


Yes, those two lines should be in the other order:

+        case 0:
+            /* SHRA_PH */
+            gen_helper_shra_ph(v1_t, t0, v1_t);
+            gen_store_gpr(v1_t, rt);
+            break;


>> +        case 1:
>> +            /* SHRA_R_PH */
>> +            gen_helper_shra_r_ph(v1_t, t0, v1_t);
>> +            gen_store_gpr(v1_t, rt);
>> +            break;
>> +        }
>> +        break;
> thanks
> -- PMM