On Mon, Mar 09, 2020 at 11:45:57PM +0300, Vitaly Chikunov wrote:
> rlwinm cannot just AND with Mask if shift value is zero on ppc64 when
> Mask Begin is greater than Mask End and high bits are set to 1.
>
> Note that PowerISA 3.0B says that for `rlwinm' ROTL32 is used, and
> ROTL32 is defined (in 3.3.14) so that rotated value should have two
> copies of lower word of the source value.
>
> This seems to be another incarnation of the fix from 820724d170
> ("target-ppc: Fix rlwimi, rlwinm, rlwnm again"), except I leave
> optimization when Mask value is less than 32 bits.
>
> Fixes: 7b4d326f47 ("target-ppc: Use the new deposit and extract ops")
> Cc: qemu-sta...@nongnu.org
> Signed-off-by: Vitaly Chikunov <v...@altlinux.org>
Adding Richard Henderson to CC, since he knows the most about ppc
target TCG.
> ---
> target/ppc/translate.c | 20 +++++++++++---------
> 1 file changed, 11 insertions(+), 9 deletions(-)
>
> diff --git a/target/ppc/translate.c b/target/ppc/translate.c
> index 36fa27367c..127c82a24e 100644
> --- a/target/ppc/translate.c
> +++ b/target/ppc/translate.c
> @@ -1938,15 +1938,17 @@ static void gen_rlwinm(DisasContext *ctx)
> me += 32;
> #endif
> mask = MASK(mb, me);
> - if (sh == 0) {
> - tcg_gen_andi_tl(t_ra, t_rs, mask);
> - } else if (mask <= 0xffffffffu) {
> - TCGv_i32 t0 = tcg_temp_new_i32();
> - tcg_gen_trunc_tl_i32(t0, t_rs);
> - tcg_gen_rotli_i32(t0, t0, sh);
> - tcg_gen_andi_i32(t0, t0, mask);
> - tcg_gen_extu_i32_tl(t_ra, t0);
> - tcg_temp_free_i32(t0);
> + if (mask <= 0xffffffffu) {
> + if (sh == 0) {
> + tcg_gen_andi_tl(t_ra, t_rs, mask);
> + } else {
> + TCGv_i32 t0 = tcg_temp_new_i32();
> + tcg_gen_trunc_tl_i32(t0, t_rs);
> + tcg_gen_rotli_i32(t0, t0, sh);
> + tcg_gen_andi_i32(t0, t0, mask);
> + tcg_gen_extu_i32_tl(t_ra, t0);
> + tcg_temp_free_i32(t0);
> + }
> } else {
> #if defined(TARGET_PPC64)
> tcg_gen_deposit_i64(t_ra, t_rs, t_rs, 32, 32);
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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