Re: [PATCH 2/2] target/tricore: Fix OPC2_32_RRPW_EXTR for width=0

[Philippe Mathieu-Daudé]

On 3/5/21 2:26 PM, Bastian Koppelmann wrote:
> if width was 0 we would run into the assertion:
> 
> qemu-system-tricore: ../upstream/tcg/tcg-op.c:217: tcg_gen_sari_i32: 
> Assertion `arg2 >= 0 && arg2 < 32' failed.o

Maybe strip "../upstream/"

> 
> The instruction manuel specifies undefined behaviour for this case. So

"manual"

> we bring this in line with the golden Infineon simlator 'tsim', which
> simply writes 0 to the result in case of width=0.
> 
> Signed-off-by: Bastian Koppelmann <kbastian@mail.uni-paderborn.de>
> ---
>  target/tricore/translate.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/target/tricore/translate.c b/target/tricore/translate.c
> index 67a7f646a2..d8b773ab37 100644
> --- a/target/tricore/translate.c
> +++ b/target/tricore/translate.c
> @@ -6998,10 +6998,16 @@ static void decode_rrpw_extract_insert(DisasContext 
> *ctx)
>      pos = MASK_OP_RRPW_POS(ctx->opcode);
>      width = MASK_OP_RRPW_WIDTH(ctx->opcode);
>  
> +

Spurious change?

>      switch (op2) {
>      case OPC2_32_RRPW_EXTR:
> +        if (width == 0) {
> +                tcg_gen_movi_tl(cpu_gpr_d[r3], 0);
> +                break;
> +        }
> +
>          if (pos + width <= 32) {
> -            /* optimize special cases */
> +                        /* optimize special cases */

Spurious change?

>              if ((pos == 0) && (width == 8)) {
>                  tcg_gen_ext8s_tl(cpu_gpr_d[r3], cpu_gpr_d[r1]);
>              } else if ((pos == 0) && (width == 16)) {
> 

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>