Re: [PATCH v3 01/11] tcg: Implement tcg_gen_{h,w}swap_{i32,i64}

[David Hildenbrand]

On 08.03.22 02:53, Richard Henderson wrote:
> Swap half-words (16-bit) and words (32-bit) within a larger value.
> Mirrors functions of the same names within include/qemu/bitops.h.
> 
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>  include/tcg/tcg-op.h |  6 ++++++
>  tcg/tcg-op.c         | 30 ++++++++++++++++++++++++++++++
>  2 files changed, 36 insertions(+)
> 
> diff --git a/include/tcg/tcg-op.h b/include/tcg/tcg-op.h
> index caa0a63612..b09b8b4a05 100644
> --- a/include/tcg/tcg-op.h
> +++ b/include/tcg/tcg-op.h
> @@ -332,6 +332,7 @@ void tcg_gen_ext8u_i32(TCGv_i32 ret, TCGv_i32 arg);
>  void tcg_gen_ext16u_i32(TCGv_i32 ret, TCGv_i32 arg);
>  void tcg_gen_bswap16_i32(TCGv_i32 ret, TCGv_i32 arg, int flags);
>  void tcg_gen_bswap32_i32(TCGv_i32 ret, TCGv_i32 arg);
> +void tcg_gen_hswap_i32(TCGv_i32 ret, TCGv_i32 arg);
>  void tcg_gen_smin_i32(TCGv_i32, TCGv_i32 arg1, TCGv_i32 arg2);
>  void tcg_gen_smax_i32(TCGv_i32, TCGv_i32 arg1, TCGv_i32 arg2);
>  void tcg_gen_umin_i32(TCGv_i32, TCGv_i32 arg1, TCGv_i32 arg2);
> @@ -531,6 +532,8 @@ void tcg_gen_ext32u_i64(TCGv_i64 ret, TCGv_i64 arg);
>  void tcg_gen_bswap16_i64(TCGv_i64 ret, TCGv_i64 arg, int flags);
>  void tcg_gen_bswap32_i64(TCGv_i64 ret, TCGv_i64 arg, int flags);
>  void tcg_gen_bswap64_i64(TCGv_i64 ret, TCGv_i64 arg);
> +void tcg_gen_hswap_i64(TCGv_i64 ret, TCGv_i64 arg);
> +void tcg_gen_wswap_i64(TCGv_i64 ret, TCGv_i64 arg);
>  void tcg_gen_smin_i64(TCGv_i64, TCGv_i64 arg1, TCGv_i64 arg2);
>  void tcg_gen_smax_i64(TCGv_i64, TCGv_i64 arg1, TCGv_i64 arg2);
>  void tcg_gen_umin_i64(TCGv_i64, TCGv_i64 arg1, TCGv_i64 arg2);
> @@ -1077,6 +1080,8 @@ void tcg_gen_stl_vec(TCGv_vec r, TCGv_ptr base, TCGArg 
> offset, TCGType t);
>  #define tcg_gen_bswap32_tl tcg_gen_bswap32_i64
>  #define tcg_gen_bswap64_tl tcg_gen_bswap64_i64
>  #define tcg_gen_bswap_tl tcg_gen_bswap64_i64
> +#define tcg_gen_hswap_tl tcg_gen_hswap_i64
> +#define tcg_gen_wswap_tl tcg_gen_wswap_i64
>  #define tcg_gen_concat_tl_i64 tcg_gen_concat32_i64
>  #define tcg_gen_extr_i64_tl tcg_gen_extr32_i64
>  #define tcg_gen_andc_tl tcg_gen_andc_i64
> @@ -1192,6 +1197,7 @@ void tcg_gen_stl_vec(TCGv_vec r, TCGv_ptr base, TCGArg 
> offset, TCGType t);
>  #define tcg_gen_bswap16_tl tcg_gen_bswap16_i32
>  #define tcg_gen_bswap32_tl(D, S, F) tcg_gen_bswap32_i32(D, S)
>  #define tcg_gen_bswap_tl tcg_gen_bswap32_i32
> +#define tcg_gen_hswap_tl tcg_gen_hswap_i32
>  #define tcg_gen_concat_tl_i64 tcg_gen_concat_i32_i64
>  #define tcg_gen_extr_i64_tl tcg_gen_extr_i64_i32
>  #define tcg_gen_andc_tl tcg_gen_andc_i32
> diff --git a/tcg/tcg-op.c b/tcg/tcg-op.c
> index 65e1c94c2d..379adb4b9f 100644
> --- a/tcg/tcg-op.c
> +++ b/tcg/tcg-op.c
> @@ -1056,6 +1056,12 @@ void tcg_gen_bswap32_i32(TCGv_i32 ret, TCGv_i32 arg)
>      }
>  }
>  
> +void tcg_gen_hswap_i32(TCGv_i32 ret, TCGv_i32 arg)
> +{
> +    /* Swapping 2 16-bit elements is a rotate. */
> +    tcg_gen_rotli_i32(ret, arg, 16);
> +}
> +
>  void tcg_gen_smin_i32(TCGv_i32 ret, TCGv_i32 a, TCGv_i32 b)
>  {
>      tcg_gen_movcond_i32(TCG_COND_LT, ret, a, b, a, b);
> @@ -1792,6 +1798,30 @@ void tcg_gen_bswap64_i64(TCGv_i64 ret, TCGv_i64 arg)
>      }
>  }
>  
> +void tcg_gen_hswap_i64(TCGv_i64 ret, TCGv_i64 arg)
> +{
> +    uint64_t m = 0x0000ffff0000ffffull;
> +    TCGv_i64 t0 = tcg_temp_new_i64();
> +    TCGv_i64 t1 = tcg_temp_new_i64();
> +
> +    /* See include/qemu/bitops.h, hswap64. */
> +    tcg_gen_rotli_i64(t1, arg, 32);> +    tcg_gen_andi_i64(t0, t1, m);
> +    tcg_gen_shri_i64(t1, t1, 16);
> +    tcg_gen_shli_i64(t0, t0, 16);

I'd flip these two lines into

tcg_gen_shli_i64(t0, t0, 16);
tcg_gen_shri_i64(t1, t1, 16);

To make it easier to map to hswap64().


Reviewed-by: David Hildenbrand <david@redhat.com>

-- 
Thanks,

David / dhildenb