Re: [PATCH 8/8] target/sparc: Fix VIS subtraction instructions.

[Richard Henderson <richard.henderson@linaro.org>]

On 9/24/23 01:03, Nick Bowler wrote:
> All of the VIS subtraction instructions are documented to subtract the
> second input operand from the first.  This is also consistent with how
> the instructions actually work on a real UltraSparc II.
> 
> But the emulator is implementing the subtraction in the wrong order,
> subtracting the first input from the second, so the results are wrong
> in all nontrivial cases.
> 
> Signed-off-by: Nick Bowler <nbowler@draconx.ca>
> ---
>   target/sparc/vis_helper.c | 18 +++++++++---------
>   1 file changed, 9 insertions(+), 9 deletions(-)

While this patch works, better to use

void tcg_gen_vec_add16_i32(TCGv_i32 d, TCGv_i32 a, TCGv_i32 b);
void tcg_gen_vec_add16_i64(TCGv_i64 d, TCGv_i64 a, TCGv_i64 b);
void tcg_gen_vec_add32_i64(TCGv_i64 d, TCGv_i64 a, TCGv_i64 b);

void tcg_gen_vec_sub16_i32(TCGv_i32 d, TCGv_i32 a, TCGv_i32 b);
void tcg_gen_vec_sub16_i64(TCGv_i64 d, TCGv_i64 a, TCGv_i64 b);
void tcg_gen_vec_sub32_i64(TCGv_i64 d, TCGv_i64 a, TCGv_i64 b);

from "tcg/tcg-op-gvec.h" and remove the sparc helpers.


r~