Re: [PATCH 09/28] tcg/ppc: Split out tcg_out_bswap64

[Peter Maydell]

On Mon, 14 Jun 2021 at 09:55, Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>  tcg/ppc/tcg-target.c.inc | 51 +++++++++++++++++-----------------------
>  1 file changed, 21 insertions(+), 30 deletions(-)
>
> diff --git a/tcg/ppc/tcg-target.c.inc b/tcg/ppc/tcg-target.c.inc
> index f0e42e4b88..690c77b4da 100644
> --- a/tcg/ppc/tcg-target.c.inc
> +++ b/tcg/ppc/tcg-target.c.inc
> @@ -809,6 +809,26 @@ static void tcg_out_bswap32(TCGContext *s, TCGReg dst, 
> TCGReg src)
>      tcg_out_mov(s, TCG_TYPE_REG, dst, tmp);
>  }
>
> +static void tcg_out_bswap64(TCGContext *s, TCGReg dst, TCGReg src)
> +{
> +    TCGReg t0 = dst == src ? TCG_REG_R0 : dst;
> +    TCGReg t1 = dst == src ? dst : TCG_REG_R0;
> +
> +                                                   /* src = abcd efgh */
> +    tcg_out_rlw(s, RLWINM, t0, src, 8, 0, 31);     /* t0  = 0000 fghe */
> +    tcg_out_rlw(s, RLWIMI, t0, src, 24, 0, 7);     /* t0  = 0000 hghe */
> +    tcg_out_rlw(s, RLWIMI, t0, src, 24, 16, 23);   /* t0  = 0000 hgfe */
> +
> +    tcg_out_rld(s, RLDICL, t0, t0, 32, 0);         /* t0  = hgfe 0000 */
> +    tcg_out_rld(s, RLDICL, t1, src, 32, 0);        /* t1  = efgh abcd */
> +
> +    tcg_out_rlw(s, RLWIMI, t0, t1, 8, 0, 31);      /* t0  = hgfe bcda */
> +    tcg_out_rlw(s, RLWIMI, t0, t1, 24, 0, 7);      /* t0  = hgfe dcda */
> +    tcg_out_rlw(s, RLWIMI, t0, t1, 24, 16, 23);    /* t0  = hgfe dcba */
> +
> +    tcg_out_mov(s, TCG_TYPE_REG, dst, t0);
> +}
> +
>  /* Emit a move into ret of arg, if it can be done in one insn.  */
>  static bool tcg_out_movi_one(TCGContext *s, TCGReg ret, tcg_target_long arg)
>  {
> @@ -2806,37 +2826,8 @@ static void tcg_out_op(TCGContext *s, TCGOpcode opc,
>      case INDEX_op_bswap32_i64:
>          tcg_out_bswap32(s, args[0], args[1]);
>          break;
> -
>      case INDEX_op_bswap64_i64:
> -        a0 = args[0], a1 = args[1], a2 = TCG_REG_R0;
> -        if (a0 == a1) {
> -            a0 = TCG_REG_R0;
> -            a2 = a1;
> -        }
> -
> -        /* a1 = # abcd efgh */
> -        /* a0 = rl32(a1, 8) # 0000 fghe */
> -        tcg_out_rlw(s, RLWINM, a0, a1, 8, 0, 31);
> -        /* a0 = dep(a0, rl32(a1, 24), 0xff000000) # 0000 hghe */
> -        tcg_out_rlw(s, RLWIMI, a0, a1, 24, 0, 7);
> -        /* a0 = dep(a0, rl32(a1, 24), 0x0000ff00) # 0000 hgfe */
> -        tcg_out_rlw(s, RLWIMI, a0, a1, 24, 16, 23);
> -
> -        /* a0 = rl64(a0, 32) # hgfe 0000 */
> -        /* a2 = rl64(a1, 32) # efgh abcd */
> -        tcg_out_rld(s, RLDICL, a0, a0, 32, 0);
> -        tcg_out_rld(s, RLDICL, a2, a1, 32, 0);
> -
> -        /* a0 = dep(a0, rl32(a2, 8), 0xffffffff)  # hgfe bcda */
> -        tcg_out_rlw(s, RLWIMI, a0, a2, 8, 0, 31);
> -        /* a0 = dep(a0, rl32(a2, 24), 0xff000000) # hgfe dcda */
> -        tcg_out_rlw(s, RLWIMI, a0, a2, 24, 0, 7);
> -        /* a0 = dep(a0, rl32(a2, 24), 0x0000ff00) # hgfe dcba */
> -        tcg_out_rlw(s, RLWIMI, a0, a2, 24, 16, 23);
> -
> -        if (a0 == 0) {
> -            tcg_out_mov(s, TCG_TYPE_REG, args[0], a0);
> -        }
> +        tcg_out_bswap64(s, args[0], args[1]);
>          break;
>

Again, keep the comments, otherwise
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

thanks
-- PMM