Re: [PATCH v2 04/18] target/riscv: Add packed SIMD averaging and rounding instructions

On 7/17/2026 7:06 AM, Molly Chen wrote:
> Signed-off-by: Molly Chen <[email protected]>
> ---

Reviewed-by: Daniel Henrique Barboza <[email protected]>

>   target/riscv/helper.h                       | 18 ++++++++++
>   target/riscv/insn32.decode                  | 26 ++++++++++++++
>   target/riscv/tcg/insn_trans/trans_rvp.c.inc | 18 ++++++++++
>   target/riscv/tcg/psimd_helper.c             | 40 +++++++++++++++++++++
>   4 files changed, 102 insertions(+)
> 
> diff --git a/target/riscv/helper.h b/target/riscv/helper.h
> index eebb2febd95..7256f776ae6 100644
> --- a/target/riscv/helper.h
> +++ b/target/riscv/helper.h
> @@ -1399,3 +1399,21 @@ DEF_HELPER_3(sati_32, i32, env, i32, i32)
>   DEF_HELPER_3(usati_32, i32, env, i32, i32)
>   DEF_HELPER_3(sati_64, i64, env, i64, i64)
>   DEF_HELPER_3(usati_64, i64, env, i64, i64)
> +
> +/* Packed SIMD - Averaging and Rounding Operations */
> +DEF_HELPER_3(paadd_b, tl, env, tl, tl)
> +DEF_HELPER_3(paadd_h, tl, env, tl, tl)
> +DEF_HELPER_3(paadd_w, i64, env, i64, i64)
> +DEF_HELPER_3(paaddu_b, tl, env, tl, tl)
> +DEF_HELPER_3(paaddu_h, tl, env, tl, tl)
> +DEF_HELPER_3(paaddu_w, i64, env, i64, i64)
> +DEF_HELPER_3(aadd, i32, env, i32, i32)
> +DEF_HELPER_3(aaddu, i32, env, i32, i32)
> +DEF_HELPER_3(pasub_b, tl, env, tl, tl)
> +DEF_HELPER_3(pasub_h, tl, env, tl, tl)
> +DEF_HELPER_3(pasub_w, i64, env, i64, i64)
> +DEF_HELPER_3(pasubu_b, tl, env, tl, tl)
> +DEF_HELPER_3(pasubu_h, tl, env, tl, tl)
> +DEF_HELPER_3(pasubu_w, i64, env, i64, i64)
> +DEF_HELPER_3(asub, i32, env, i32, i32)
> +DEF_HELPER_3(asubu, i32, env, i32, i32)
> diff --git a/target/riscv/insn32.decode b/target/riscv/insn32.decode
> index 8da13669d73..005cc055b8a 100644
> --- a/target/riscv/insn32.decode
> +++ b/target/riscv/insn32.decode
> @@ -1147,3 +1147,29 @@ pusati_h   10100 001.... ..... 100 ..... 0011011 @p_ui16
>   }
>   sati_64    111001 ...... ..... 100 ..... 0011011 @p_ui64
>   usati_64   101001 ...... ..... 100 ..... 0011011 @p_ui64
> +
> +# Packed SIMD - Averaging and Rounding Operations
> +paadd_b    1001110 ..... ..... 000 ..... 0111011 @r
> +paadd_h    1001100 ..... ..... 000 ..... 0111011 @r
> +{
> +  aadd     1001101 ..... ..... 000 ..... 0111011 @r
> +  paadd_w  1001101 ..... ..... 000 ..... 0111011 @r
> +}
> +paaddu_b   1011110 ..... ..... 000 ..... 0111011 @r
> +paaddu_h   1011100 ..... ..... 000 ..... 0111011 @r
> +{
> +  aaddu    1011101 ..... ..... 000 ..... 0111011 @r
> +  paaddu_w 1011101 ..... ..... 000 ..... 0111011 @r
> +}
> +pasub_b    1101110 ..... ..... 000 ..... 0111011 @r
> +pasub_h    1101100 ..... ..... 000 ..... 0111011 @r
> +{
> +  asub     1101101 ..... ..... 000 ..... 0111011 @r
> +  pasub_w  1101101 ..... ..... 000 ..... 0111011 @r
> +}
> +pasubu_b   1111110 ..... ..... 000 ..... 0111011 @r
> +pasubu_h   1111100 ..... ..... 000 ..... 0111011 @r
> +{
> +  asubu    1111101 ..... ..... 000 ..... 0111011 @r
> +  pasubu_w 1111101 ..... ..... 000 ..... 0111011 @r
> +}
> diff --git a/target/riscv/tcg/insn_trans/trans_rvp.c.inc b/target/riscv/tcg/insn_trans/trans_rvp.c.inc
> index 056ccfb486e..43c59aef182 100644
> --- a/target/riscv/tcg/insn_trans/trans_rvp.c.inc
> +++ b/target/riscv/tcg/insn_trans/trans_rvp.c.inc
> @@ -545,3 +545,21 @@ GEN_SIMD_TRANS_IMM_32_VXSAT(usati_32)
>   GEN_SIMD_TRANS_IMM_64_VXSAT(sati_64)
>   GEN_SIMD_TRANS_IMM_64_VXSAT(usati_64)
>   
> +/* Packed SIMD - Averaging and Rounding Operations */
> +GEN_SIMD_TRANS(paadd_b)
> +GEN_SIMD_TRANS(paadd_h)
> +GEN_SIMD_TRANS_64(paadd_w)
> +GEN_SIMD_TRANS(paaddu_b)
> +GEN_SIMD_TRANS(paaddu_h)
> +GEN_SIMD_TRANS_64(paaddu_w)
> +GEN_SIMD_TRANS_32(aadd)
> +GEN_SIMD_TRANS_32(aaddu)
> +GEN_SIMD_TRANS(pasub_b)
> +GEN_SIMD_TRANS(pasub_h)
> +GEN_SIMD_TRANS_64(pasub_w)
> +GEN_SIMD_TRANS(pasubu_b)
> +GEN_SIMD_TRANS(pasubu_h)
> +GEN_SIMD_TRANS_64(pasubu_w)
> +GEN_SIMD_TRANS_32(asub)
> +GEN_SIMD_TRANS_32(asubu)
> +
> diff --git a/target/riscv/tcg/psimd_helper.c b/target/riscv/tcg/psimd_helper.c
> index 52c58e0287e..162041a8f18 100644
> --- a/target/riscv/tcg/psimd_helper.c
> +++ b/target/riscv/tcg/psimd_helper.c
> @@ -1768,3 +1768,43 @@ GEN_PSIMD_SATI(sati_64, uint64_t, int64_t, int64_t,
>   GEN_PSIMD_USATI(usati_64, uint64_t, int64_t, uint64_t, uint64_t,
>                   EXTRACT64, INSERT64, ELEMS_D, 1ULL)
>   
> +/* Averaging Operations (non-saturating) */
> +
> +GEN_PSIMD_AVG_BINOP(paadd_b, target_ulong, int8_t, int16_t,
> +                    EXTRACT8, INSERT8, ELEMS_B, PSIMD_DO_ADD)
> +GEN_PSIMD_AVG_BINOP(paadd_h, target_ulong, int16_t, int32_t,
> +                    EXTRACT16, INSERT16, ELEMS_H, PSIMD_DO_ADD)
> +GEN_PSIMD_AVG_BINOP(paadd_w, uint64_t, int32_t, int64_t,
> +                    EXTRACT32, INSERT32, ELEMS_W, PSIMD_DO_ADD)
> +
> +GEN_PSIMD_AVG_BINOP(paaddu_b, target_ulong, uint8_t, uint16_t,
> +                    EXTRACT8, INSERT8, ELEMS_B, PSIMD_DO_ADD)
> +GEN_PSIMD_AVG_BINOP(paaddu_h, target_ulong, uint16_t, uint32_t,
> +                    EXTRACT16, INSERT16, ELEMS_H, PSIMD_DO_ADD)
> +GEN_PSIMD_AVG_BINOP(paaddu_w, uint64_t, uint32_t, uint64_t,
> +                    EXTRACT32, INSERT32, ELEMS_W, PSIMD_DO_ADD)
> +
> +GEN_PSIMD_AVG_BINOP(aadd, uint32_t, int32_t, int64_t,
> +                    EXTRACT32, INSERT32, ELEMS_W, PSIMD_DO_ADD)
> +GEN_PSIMD_AVG_BINOP(aaddu, uint32_t, uint32_t, uint64_t,
> +                    EXTRACT32, INSERT32, ELEMS_W, PSIMD_DO_ADD)
> +
> +GEN_PSIMD_AVG_BINOP(pasub_b, target_ulong, int8_t, int16_t,
> +                    EXTRACT8, INSERT8, ELEMS_B, PSIMD_DO_SUB)
> +GEN_PSIMD_AVG_BINOP(pasub_h, target_ulong, int16_t, int32_t,
> +                    EXTRACT16, INSERT16, ELEMS_H, PSIMD_DO_SUB)
> +GEN_PSIMD_AVG_BINOP(pasub_w, uint64_t, int32_t, int64_t,
> +                    EXTRACT32, INSERT32, ELEMS_W, PSIMD_DO_SUB)
> +
> +GEN_PSIMD_AVG_BINOP(pasubu_b, target_ulong, uint8_t, uint16_t,
> +                    EXTRACT8, INSERT8, ELEMS_B, PSIMD_DO_SUB)
> +GEN_PSIMD_AVG_BINOP(pasubu_h, target_ulong, uint16_t, uint32_t,
> +                    EXTRACT16, INSERT16, ELEMS_H, PSIMD_DO_SUB)
> +GEN_PSIMD_AVG_BINOP(pasubu_w, uint64_t, uint32_t, uint64_t,
> +                    EXTRACT32, INSERT32, ELEMS_W, PSIMD_DO_SUB)
> +
> +GEN_PSIMD_AVG_BINOP(asub, uint32_t, int32_t, int64_t,
> +                    EXTRACT32, INSERT32, ELEMS_W, PSIMD_DO_SUB)
> +GEN_PSIMD_AVG_BINOP(asubu, uint32_t, uint32_t, uint64_t,
> +                    EXTRACT32, INSERT32, ELEMS_W, PSIMD_DO_SUB)
> +